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BI-MONTHLY MAGAZINE OF SCIENTIFIC 4 The definitive discovery of organics AND TECHNICAL INFORMATION on Mars FREELY AVAILABLE THROUGH THE INTERNET 14 The Pillars of Creation seen by Webb January-February 2023 16 Heaviest element yet detected in an exoatmosphere 20 Record-breaking galaxies in Abell 2744 English edition of the magazine 22 Largest NEA detected in eight years ASl’ TROFILO 26 Kilonovae, a target for the Roman Editor in chief Space Telescope Michele Ferrara 32 WASP-39 b’s atmosphere as never seen Scientific advisor before Prof. Enrico Maria Corsini 40 Astronomers discover closest black hole Publisher to Earth Astro Publishing di Pirlo L. Via Bonomelli, 106 44 Three faces of evolving supernova 25049 Iseo - BS - ITALY in early Universe email [email protected] 46 Most distant detection of a black hole Internet Service Provider swallowing a star Aruba S.p.A. Via San Clemente, 53 48 ‘Marshmallow’ world orbiting a cool red 24036 Ponte San Pietro - BG - ITALY dwarf star Copyright All material in this magazine is, unless otherwise stated, property of Astro Publishing di Pirlo L. or included with permission of its author. Reproduction or retransmission of the materials, in whole or in part, in any manner, with- out the prior written consent of the copyright holder, is a violation of copy- right law. A single copy of the materi- als available through this course may be made, solely for personal, noncom- mercial use. Users may not distribute such copies to others, whether or not in electronic form, whether or not for a charge or other consideration, with- out prior written consent of the copy- right holder of the materials. The publisher makes available itself with having rights for possible not charac- terized iconographic sources. Advertising - Administration Astro Publishing di Pirlo L. Via Bonomelli, 106 25049 Iseo - BS - ITALY email [email protected]
4 ASTRO PUBLISHING The definitive discovery of organics on Mars by Damian G. Allis NASA Solar System Ambassador W e are close to the two-year gates Geologically Rich Mars Ter- N ASA’s Perseverance Mars rover mark for the NASA Mars rain,” from September 15th) reports looks out at an expanse of boul- 2020 mission exploration the detection of organic molecules ders on the landscape in front of a of Jezero Crater, home of an ancient within clay samples taken from location nicknamed “Santa Cruz” on lake fed, in some small or large part, “Wildcat Ridge,” a large and acces- Feb. 16, 2022, the 353rd Martian day, by an ancient river. The dry remains sible representative of the sedimen- or sol, of the mission. This panorama of this river, a delta replete with the tary rocks that are abundant in the is made up of 24 individual images kinds of clay deposits that are known delta. from the rover’s Mastcam-Z camera to form slowly and only in water This new detection of surface organ- system, stitched together after they here on Earth, are now the focus of ics at Wildcat Ridge by no means were sent back from Mars. The sample collection and select chemi- marks the first detection of Martian tonality of the image has been en- cal analyses by the onboard labora- organics. The Curiosity rover had di- hanced to make the landscape more tory of the Perseverance rover rectly detected benzoic acid back in similar to the Earth’s environment, (“Percy” for short). An announce- 2021, benzene, toluene, and short- making it easier for the science team ment from the NASA Mars website chain organic molecules back in to interpret surface features. (“NASA’s Perseverance Rover Investi- 2018, and chlorinated organic mole- [NASA/JPL-Caltech/ASU/MSSS]
ASTRO PUBLISHING 5 cules as far back as 2013 (with the T he first definitive detection of Martian organic chemicals in material on the caveat that the chemical analysis surface of Mars came from analysis by NASA’s Curiosity Mars rover of sample method used to determine the pres- powder from this mudstone target, “Cumberland.” [NASA/JPL-Caltech/MSSS] ence of carbon may have also been responsible for the addition of chlo- the descriptor “organic” spans the to as covalent bonds, they qualify. rine from the prevalent surface per- gigantic chemical space of molecules This includes the simple molecule chlorate material onto those organic vital to life, molecules capable of de- methane (containing one carbon molecules – but carbon was defi- stroying life both slowly (carcino- atom and four hydrogen atoms − nitely detected). This Wildcat Ridge gens) or quickly (TNT or RDX), CH4), the amino and nucleic acids discovery is, itself, the second major laboratory molecules synthesized that make up your proteins and news announcement from Persever- with no direct connection to life at DNA, interstellar polycyclic aromatic ance concerning the detection of or- all, and all other carbon-containing hydrocarbons (PAHs), and carbon- ganics on Mars, the first having been molecules. So long as one or more containing molecules of all sizes in reported at an American Geophysi- carbon atoms are connected to ei- between. The definition of “organic cal Union conference back in late ther other carbon atoms or any molecule” is even broad enough ac- 2021. Upon reconsideration of the other atoms in the Periodic Table by cording to some scientists that it in- experiments, it is arguable that the the strong chemical bonds referred cludes the single diamond crystal NASA Viking Landers also detected trace organic material on the ground back in 1976. If the reports from Mars had been “no detectable organic molecules anywhere,” that would have been the much more surprising story, as then scientists would have had to come up with scenarios describing why an element (carbon) was not present on such a large, rocky body so close to a planet where carbon made possible the evolution of life and the development of the scien- tists who now exist to perform such measurements! Organic molecules are, simply, mol- ecules containing carbon atoms. Just as saying “I can read” does not, by itself, provide much information about what languages you can read,
T his image of the parachute that tutes a nontrivial amount. The per- bon by mass, exceeded only by the helped deliver NASA’s Persever- centages vary when we restrict the 65% oxygen mass that includes the ance Mars rover to the Martian sur- analysis to certain objects. Mete- water we carry within us – making face was taken by the rover’s orites, largely composed of iron and this high carbon percentage a dra- Mastcam-Z instrument on April 6, nickel left over from the formation matic localization of one element 2022. [NASA/JPL-Caltech/ASU/MSSS] of the solar system, are 1.5% carbon compared to the natural abun- on average, with carbonaceous that might be embedded in a ring chondrites achieving higher per- T he expanse of Jezero Crater’s on your finger. centages due to the presence of or- river delta is shown in this Carbon is neither abundant nor ganic molecules and carbon-rich panorama of 64 stitched-together scarce, making up just under 0.5% minerals. The Earth’s crust, domi- images taken by the Mastcam-Z sys- of all atoms in the entire universe. nated by oxygen and silicon, con- tem on NASA’s Perseverance Mars In a universe that is 75% hydrogen tains only 0.02% carbon. Turning to rover on April 11, 2022, the 406th and 23% helium, being 25% of the carbon content of living organ- Martian day, or sol, of the mission. “everything else” certainly consti- isms, we find humans are 18% car- [NASA/JPL-Caltech/ASU/MSSS]
ASTRO PUBLISHING 7 dances in the non-biological mate- of energy needed to break and T his video taken by NASA’s Perse- rial that makes up the surface of the make these bonds to form other, verance Mars rover shows some planet we call home. more varied, or more complex mol- of the terrain the rover had to nego- The term “organic” does not mean ecules. Nature’s solution has been tiate during its drive to the delta at “biological,” but “biological,” as two-fold. To solve part of the biosyn- Jezero Crater in April 2022. well as our current understanding of thesis of complex organic molecules, [NASA/JPL-Caltech] how life evolves and works “at all,” Nature relies on the catalytic activity necessarily means “organic.” The of some proteins, which contain To solve the complex issue of com- chemical logic to the significant car- within their complex folded struc- bining small molecules, such as bon content in ourselves applies ture sites that can bind one or more amino acids, into larger molecules, here on Earth just as it would have molecules in a way that lowers the such as proteins, Nature has instead in the ancient history of Mars. Cova- amount of energy required to per- chosen to forego making long lent bonds to carbon are strong form some chemical reaction. Just as chains of strong carbon-carbon enough to persist across a wide a woodworker relies on a jig to hold bonds and instead relies on connect- range of environmental conditions, wood in place or a surgeon relies on ing amino and nucleic acids by using yet can enable molecules to flop, assistants to hold instruments during more reactive, but still stable, bonds twist, and turn around those same a procedure, proteins can bind and involving the removal of one water bonds. When combined with oxy- constrain molecules in such a way molecule with the formation of each gen, nitrogen, and hydrogen atoms, that a select chemical reaction be- chemical bond – a chemical process organic molecules can be fine-tuned comes possible with much greater known as a condensation reaction. like a lock and key, both in nature probability and much lower energy In DNA, two nucleic acids are joined and in the laboratory, to make cer- than it would if those same mole- with the removal of one water and tain kinds of interactions between cules were simply floating around the formation of a phosphodiester pairs of molecules that also lead to unconstrained in a laboratory flask bond between phosophorus and environmentally persistent geome- or some primordial pool of water. oxygen, each bound to the organic tries. The C-G and A-T base pairs in DNA are, by far, the most famous ex- amples of this exquisite pairing of interactions between molecules, or intermolecular interactions, produc- ing a structure that can persist in water, frozen for millennia encased in amber, or even for one-million years in the tooth of a mammoth – a record-breaking age reported by scientists at the Centre for Palaeoge- netics in Stockholm back in 2021. In terms of the development of life on Earth, the strength of carbon bonds in small organic molecules does not come without some cost. In biology, this cost comes in the form
8 ASTRO PUBLISHING N ASA’s Perseverance rover puts hydrogen (OH) fragment from a car- is within liquid water that the pep- its robotic arm to work around a bon on one molecule and a single tide chain has the freedom to flop, rocky outcrop called “Skinner Ridge” hydrogen from a nitrogen on an- spin around bonds, fold and unfold in Mars’ Jezero Crater. Composed of other to also form a departing H2O into different geometries on the multiple images, this mosaic shows molecule. way to its favored geometry, jiggle layered sedimentary rocks in the In both the reliance on proteins as and undulate to modify the shape of face of a cliff in the delta, as well as catalysts and the formation of pep- its molecular binding pocket, and one of the locations where the rover tide bonds in proteins and phospho- allow for the delivery and removal abraded a circular patch to analyze diester bonds in DNA, Nature relies of whatever molecules are being a rock’s composition. [NASA/JPL-Cal- on a key ingredient − liquid water. It modified that might be floating in tech/ASU/MSSS] framework of the A/T/C/G bases. In proteins, the formation of a peptide bond between two amino acids re- sults in the removal of an oxygen- A close-up view of an engineering model of SHERLOC (Scanning Habitable Environments with Raman & Lumi- nescence for Organics & Chemicals), one the instruments aboard NASA’s Perseverance Mars rover. Located on the end of the rover’s robotic arm, this instrument features an auto- focusing camera (pictured) that shoots black-and-white im- ages used by SHERLOC’s color camera, called WATSON (Wide Angle Topographic Sensor for Operations and eNgi- neering), to zero in on rock textures. SHERLOC also has a laser, which aims for the dead center of rock surfaces de- picted in WATSON’s images. The laser uses a technique called Raman spectroscopy to detect minerals in microscopic rock features; that data is then superimposed on WATSON’s images. These mineral maps help scientists determine which rock samples Perseverance should drill so that they can be sealed in metal tubes and left on the Martian surface for a future mission to return to Earth. [NASA/JPL-Caltech] JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 9 the intracellular matrix. The and the transition from simple mol- S ample tube number 266 information stored in DNA is ecules to the simplest organisms is was used to collect the only accessible because it can dwarfed by the many volumes that first sample of Martian rock be uncoiled, read, repaired, could be written about those things by NASA’s Perseverance and recombined in the fluid rover. The laser-etched serial chemical environment within number helps science team the water-filled cell. Liquid identify the tubes and their water, by the fact that it is not contents. [NASA/JPL-Caltech] frozen into a crystalline lattice of ice, also provides the we currently do not know medium within which all of about that same transition. It these small, biologically rele- may come to pass that the vant molecules can come to books describing the things be in close proximity and com- “we do not know that we do bine to make larger, biologi- not know” may eventually be cally relevant molecules. This larger still. is why the several recent dis- With all that said about the coveries of salty subsurface chemistry of life on Earth, we pockets of liquid water on return to the issue of simple Mars are specifically exciting organic molecules on the sur- to astrobiologists – simply ex- face of an ancient, frozen, isting in a liquid form means and barren planet unpro- chemical processes can be oc- tected for billions of years curring that are otherwise im- from solar radiation of all possible in solid ice, even if wavelengths. the salt content and still ex- The samples from Wildcat tremely cold temperatures Ridge are unique among all significantly impact the rates and di- previous finds on Mars because of rections of those reactions. the high concentration of organics The book describing all we currently detected by the SHERLOC (Scanning know about the chemistry of life Habitable Environments with L eft, this sealed titanium sample tube contains Perseverance’s first cored sample of Mars rock. The rover’s Sampling and Caching System Camera (known as CacheCam) captured this image. Right, Perseverance’s first cored-rock sample of Mars rock is seen inside its titanium container tube in this image taken by the CacheCam. [NASA/JPL-Caltech] JANUARY-FEBRUARY 2023
10 ASTRO PUBLISHING Raman & Luminescence for Organics species for which time, radiation, of producing them – the existence of & Chemicals) apparatus onboard and chemistry might have eventually methanol and ethanol both in our Percy. Like the discovery of “the produced the right conditions for bodies and in the cold vacuum of in- most distant galaxy ever” or “the the earliest of biologically relevant terstellar clouds is certainly proof of largest prime number yet discov- processes to occur if Mars had not this point. Without invoking a ered,” we await Percy’s arrival at a gone from life-sustaining to dry and higher power, hyperdimensional new location in the Jezero delta inhospitable on its surface over alien seeding, or a rather complex where such organic molecule con- three billion years ago. These mole- time travel scenario, it can be stated centrations may be considerably cules might also simply have been with very high confidence that the higher still. Unfortunately, the deposited and concentrated as the chemistry of life did not begin with equipment onboard Perseverance ancient river delta dried up during proteins and DNA, but that larger does not allow for the detailed char- the transition of the river delta, and and more complex molecules are acterization of the types and variety Mars itself, to what we know it as one of the key steppingstones on of molecules collected on the sur- today, with the right conditions for the road to life as we know it. At our face. The molecules might have life or its pre-biotic chemical under- current level of understanding, we been ancient waste products of bio- pinnings never having been simply do not know if the organic logical processes or the molecular achieved at all. molecules we’ve detected might debris of long-extinct living organ- The problem with simple molecules have been the eventual cause of life isms. Alternatively, these organics is that both biological and non-bio- on Mars, the products of living might be the small, simple molecular logical processes are equally capable processes on Mars, or of absolutely T his pair of images shows two cylinders of rock the size of classroom chalk inside the drill of NASA’s Perseverance rover from an outcrop called “Wildcat Ridge” in Mars’ Jezero Crater. The image of the rock core on the left, called “Hazeltop,” was taken by Perseverance’s Mastcam-Z instrument on July 25, 2022, the 509th Martian day, or sol, of the mission. The image on the right, of the rock core called “Bearwallow,” was taken on Aug. 2, 2022, the 516th sol. Each core is about 0.5 inches, or 13 millimeters, in diameter and 2.4 inches, or 60 millimeters, long. They were taken from an ancient river delta in Jezero Crater, a fan-shaped area where, billions of years ago, a river once flowed into a lake and deposited rocks and sediment. Sci- entists interpret these rocks to be fine-grained sedimentary rocks. They appear to have formed under saltwater conditions, possibly as water from the crater’s ancient lake was evaporating. These rock cores have been sealed in ultra-clean sample tubes and stored in Perseverance’s Sampling and Caching System as part of the mission’s search for ancient signs of micro- bial life. The verification of ancient life on Mars carries an enormous burden of proof. [NASA/JPL-Caltech/ASU/MSSS] JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 11 T his annotated map shows the locations where NASA’s Persever- ance Mars rover collected its first witness tube and filled its first six samples. The name that the Perse- verance science and op- erations teams used to define a rock target on the Martian surface ap- pears at the top of each inset image. Also indi- cated is the Martian day, or sol, of the rover’s mis- sion and whether the image shows a target that has been abraded for proximity science or from which a core sam- ple was taken. Before collecting a sample, Per- severance uses its drill to abrade the upper few millimeters of the rock surface close to the in- tended coring target. Those inset images anno- tated with the word “abrade” were captured by the rover’s WATSON imager. Those with “core” were taken by the rover’s CacheCam, which visually inspects a sample tube after a coring event takes place. [NASA/JPL-Caltech/ASU/MSSS] no relevance to life whatsoever. This own stellar backyard need not be That all said, organic molecules are is certainly one of the key reasons complex, intelligent life – “simple, virtually everywhere we look and why astrobiologists are eager for stupid life” would be just as revolu- exist in abundance in locations, such sample return missions from Mars, tionary. With this first discovery, we as Titan, that we suspect are inca- enabling us to subject every mole- would go from being the only pable of substantiating, much less cule within a given sample to the planet we know of on which life sustaining, life as we know it. The complete array of spectroscopic arose, to being the second planet in leaps from simple organic molecules tools science has to offer to deter- our own solar system to also qualify, to complex macromolecules to en- mine exactly what, how much, and dramatically changing the percep- capsulated macromolecules in sim- how complex each unique chemical tion we have about the uniqueness ple cell-like structures to whatever species might be. If all goes well, the of life in the universe. If this discov- the first unicellular organisms might NASA Mars Sample Return mission ered life were found to share the have been are wider than the 3,000 hopes to make this eager need a re- same means of genetic information km wide Valles Marineris – the solar ality as early as 2033. storage (DNA) and retrieval (pro- system’s largest canyon – also on The irrefutable discovery of life any- teins), we would then have to have Mars. We’ve little more than strong where else in the solar system, be it the further debate over whether chemical identifiers for simple or- extant or extinct, would be the most “these seem to be the molecules ganic molecules in limited collected important discovery in human his- that, under the conditions of our samples and our own understanding tory – rivaled only by the discovery solar system formation, became the of how and where life has existed that some organism or some species means to life” or “such a similarity here on Earth to guide our search much more intelligent was attempt- almost necessitates that it all started for hard evidence for or against life, ing to contact humanity. Further- on one planet and found its way to or even chemical complexity hinting more, this greatest discovery in our the other.” at biological process, on Mars. JANUARY-FEBRUARY 2023
ALTAZIMUTH NEWTONIAN TELESCOPE ➤ SCHOTT Supremax 33 optics ➤ optical diameter: 460 mm ➤ useful diameter: 450 mm ➤ focal ratio: f/4 ➤ primary mirror thickness: 35 mm ➤ minor axis secondary mirror: 100 mm ➤ axial cell cooling system ➤ multi-fan removal of the mirror surface boundary layer ➤ carbon truss with self-centering conical couplings ➤ lateral supports (six) designed for altazimuth instruments ➤ zero deformations The NortheK Rapido 450 is designed to be disassembled into essential parts for transport in a small car. Each component is equipped with its own case, facilitating transport and assembly. The main element weighs 27 kg. Incorporated mechanical devices and the precise execution of each component allows for the collimation of the optics with extreme ease, maintaining collimation throughout an observation session while eliminating twisting and bending, regardless of the weight of the accessories used. The very thin primary optic allows for rapid acclimatization and ensures thermal stability throughout the night. Two bars equipped with sliding weights allow for the perfect balance of the telescope and accessories. On demand, it is also possible to modify the support to mount the telescope on an equatorial platform. This instrument is composed of aluminum, carbon and steel, each perfectly selected according to strict mechanical standards. It is undoubtedly the best altazimuth Newtonian on the market.
www.northek.it www.facebook.com/northek.it [email protected] phone +39 01599521 images by Massimo Vesnaver
14 ASTRO PUBLISHING The Pillars of Creation seen by Webb by NASA/ESA/CSA Claire Blome Christine Pulliam NASA, ESA, CSA, STScI − Joseph DePasquale (STScI), Alyssa Pagan (STScI) JANUARY-FEBRUARY 2023
15 NASA's James Webb Space Tel- the fringes of the pillars. In con- escope produced this spec- trast, the blue stars that dot the tacular scene from the Pil- scene are aging, which means they lars of Creation, where a “ghost” have shed most of their layers of haunts the crag in the lower left, a gas and dust. gargoyle-like shape snarls toward Mid-infrared light excels at observ- the middle of the frame, and a ing gas and dust in extreme detail. dark horse’s head charges out of This is also unmistakable through- the edge of the second pillar. The out the background. The densest newly formed stars take on the ap- areas of dust are the darkest pearance of protruding, bloodshot shades of gray. The red region to- eyes. And in the background, dust ward the top, which forms an un- dances like heavy, ancient curtains canny V, like an owl with out- being pulled shut. Instead, dust in stretched wings, is where the dust Webb’s image is like the dawn. It is is diffuse and cooler. Notice that no an essential ingredient for star for- background galaxies make an ap- mation. Though cloaked, these pil- pearance – the interstellar medium lars are bursting with activity. in the densest part of the Milky Newly forming stars hide within Way’s disk is too swollen with gas these dark gray chambers, and oth- and dust to allow their distant light ers, like red rubies, have jumped to penetrate. How vast is this land- into view. Over time, Webb’s mid- scape? Trace the topmost pillar, infrared image will allow re- landing on the bright red star jut- searchers to deeply explore the gas ting out of its lower edge like a and dust in this region, and more broomstick. This star and its dusty precisely model how stars form shroud are larger than the size of over millions of years. our entire solar system. Why does mid-infrared light set such This scene was first captured by a somber, chilling mood in Webb’s NASA’s Hubble Space Telescope in Mid-Infrared Instrument (MIRI) 1995 and revisited in 2014, but image? Interstellar dust cloaks the many other observatories, like scene. And while mid-infrared light NASA’s Spitzer Space Telescope, specializes in detailing where dust is, have also gazed deeply at the Pillars the stars aren’t bright enough at of Creation. With every observation, these wavelengths to appear. In- astronomers gain new information, stead, these looming, leaden-hued and through their ongoing research pillars of gas and dust gleam at their build a deeper understanding of edges, hinting at the activity within. this star-forming region. Thousands and thousands of stars Each wavelength of light and ad- have formed in this region. vanced instrument delivers far more This is made plain when examining precise counts of the gas, dust, and Webb’s recent Near-Infrared Cam- stars, which inform researchers’ era (NIRCam) image. In MIRI’s view, models of how stars form. the majority of the stars appear As a result of the new MIRI image, missing. Why? Many newly formed astronomers now have higher reso- stars are no longer surrounded by lution data in mid-infrared light enough dust to be detected in mid- than ever before, and will analyze infrared light. Instead, MIRI ob- its far more precise dust measure- serves young stars that have not ments to create a more complete yet cast off their dusty “cloaks.” three-dimensional landscape of this These are the crimson orbs toward distant region. JANUARY-FEBRUARY 2023
16 ASTRO PUBLISHING Heaviest element yet detected in an exoatmosphere by ESO - Juan Carlos Muñoz Mateos Using the European South- ern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have dis- covered the heaviest ele- ment ever found in an exoplanet atmosphere — barium. They were sur- prised to discover bar- ium at high altitudes in the atmospheres of the ultra-hot gas giants WASP-76 b and WASP- 121 b — two exoplan- ets, planets which orbit stars outside our Solar System. This unexpected discovery raises questions about what these exotic atmospheres may be like. “The puzzling and counter- intuitive part is: why is there such a heavy element in the upper layers of the atmosphere of these planets?” says Tomás Azevedo Silva, a PhD student at the University of Porto and the Insti- tuto de Astrofísica e Ciências do Espaço (IA) in Portugal who led the study published in Astronomy & As- trophysics. JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 17 T his artist’s impression shows an ultra-hot exoplanet, a planet beyond our WASP-76 b and WASP-121 b are Solar System, as it is about to transit in front of its host star. When the light no ordinary exoplanets. Both are from the star passes through the planet’s atmosphere, it is filtered by the chemi- known as ultra-hot Jupiters as they cal elements and molecules in the gaseous layer. With sensitive instruments, the are comparable in size to Jupiter signatures of those elements and molecules can be observed from Earth. Using the ESPRESSO instrument of ESO’s Very Large Telescope, astronomers have whilst having extremely high sur- found the heaviest element yet in an exoplanet’s atmosphere, barium, in the face temperatures soaring two ultra-hot Jupiters WASP-76 b and WASP-121 b. [ESO/M. Kornmesser] above 1000°C. This is due to their close proximity to their host stars, which also means an orbit around each star takes only one to two days. This gives these planets rather ex- otic features; in WASP- 76 b, for example, astronomers suspect it rains iron. But even so, the scientists were surprised to find barium, which is 2.5 times heavier than iron, in the upper atmospheres of WASP-76 b and WASP-121 b. “Given the high gravity of the planets, we would expect heavy elements like barium to quickly fall into the lower layers of the atmosphere,” ex- plains co-author Olivier Demangeon, a researcher also from the University of Porto and IA. “This was in a way an ‘accidental’ discovery,” says Azevedo Silva. “We were not expecting or looking for barium in particular and had to cross-check that this was actually coming from the planet since it had never been seen in any exoplanet before.” The fact that barium was detected in the atmospheres of both of these ultra-hot Jupiters suggests that this category of planets might be even stranger than previously thought. Although we do occasionally see barium in our own skies, as the bril- liant green colour in fireworks, the question for scientists is what natu- ral process could cause this heavy el- JANUARY-FEBRUARY 2023
T his illustration shows a night-side view of the exoplanet WASP-76 b. The ultra-hot giant exoplanet has a day side where temperatures climb above 2400 degrees Celsius, high enough to vaporise metals. Strong winds carry iron vapour to the cooler night side where it condenses into iron droplets. To the left of the image, we see the evening border of the ex- oplanet, where it transitions from day to night. [ESO/M. Kornmesser] U sing ESO’s Very Large Telescope, ement to be at such high altitudes in pheres ultra-hot Jupiters are ex- barium has been detected in the these exoplanets. “At the moment, tremely useful. As Demangeon ex- atmosphere of two exoplanets. The we are not sure what the mecha- plains: “Being gaseous and hot, video summarizes the discovery. [ESO] nisms are,” explains Demangeon. their atmospheres are very ex- In the study of exoplanet atmos- tended and are thus easier to ob- serve and study than those of smaller or cooler planets.” Determining the composition of an JANUARY-FEBRUARY 2023
T he ultra-hot giant exoplanet WASP-76 b orbits the star WASP-76, located some 390 light-years away in the constellation of Pisces. This video takes us on a jour- ney to this system. Observations of WASP-76 b using ESO’s Very Large Telescope (VLT) suggest it rains iron on this extreme exoplanet. [ESO/L.Calçada/spaceengine.org] exoplanet’s atmosphere requires ements in them, including barium. ing Extremely Large Telescope (ELT), very specialised equipment. The These new results show that we astronomers will be able to study team used the ESPRESSO instrument have only scratched the surface of the atmospheres of exoplanets large on ESO’s VLT in Chile to analyse the mysteries of exoplanets. With and small, including those of rocky starlight that had been filtered future instruments such as the high- planets similar to Earth, in much through the atmospheres of WASP- resolution ArmazoNes high Disper- greater depth and to gather more 76 b and WASP-121 b. This made it sion Echelle Spectrograph (ANDES), clues as to the nature of these possible to clearly detect several el- which will operate on ESO’s upcom- strange worlds. JANUARY-FEBRUARY 2023
Record-breaking galaxies in Abell 2744 by NASA/ESA/CSA les, principal investigator on one of plified Survey from Space (GLASS), Ray Villard the Webb programs. “Once again and the Cosmic Evolution Early Re- Christine Pulliam the universe has surprised us. These lease Science survey (CEERS). early galaxies are very unusual in With just four days of analysis, re- A few days after officially many ways.” searchers found two exceptionally starting science operations, Two research papers, led by Marco bright galaxies in the GLASS-JWST NASA’s James Webb Space Castellano of the National Institute images. These galaxies existed ap- Telescope propelled astronomers for Astrophysics in Rome, Italy, and proximately 450 and 350 million into a realm of early galaxies, previ- Rohan Naidu of the Harvard-Smith- years after the big bang (with a red- ously hidden beyond the grasp of all sonian Center for Astrophysics and shift of approximately 10.5 and 12.5, other telescopes until now. the Massachusetts Institute of Tech- respectively), though future spectro- “Everything we see is new. Webb is nology in Cambridge, Massachu- scopic measurements with Webb showing us that there’s a very rich setts, have been published in The will help confirm. universe beyond what we imag- Astrophysical Journal Letters. “With Webb, we were amazed to ined,” said Tommaso Treu of the These initial findings are from a find the most distant starlight that University of California at Los Ange- broader Webb research initiative in- anyone had ever seen, just days volving two Early Release Science after Webb released its first data,” (ERS) programs: the Grism Lens-Am- said Naidu of the more distant JANUARY-FEBRUARY 2023
NASA, ESA, CSA, Tommaso Treu (UCLA) − Zolt G. Levay (STScI) 21 GLASS galaxy, referred to as GLASS- the University of Geneva in Switzer- team was struck by being able to z12, which is believed to date back land, second author of the Naidu et measure the shapes of these first to 350 million years after big bang. al. paper. galaxies; their calm, orderly disks The previous record holder is galaxy The Webb observations nudge as- question our understanding of how GN-z11, which existed 400 million tronomers toward a consensus that the first galaxies formed in the years after the big bang (redshift an unusual number of galaxies in crowded, chaotic early universe.” 11.1), and was identified in 2016 by the early universe were so much This remarkable discovery of com- Hubble and Keck Observatory in brighter than expected. This will pact disks at such early times was deep-sky programs. make it easier for Webb to find even only possible because of Webb’s “Based on all the predictions, we more early galaxies in subsequent much sharper images, in infrared thought we had to search a much deep sky surveys, say researchers. light, compared to Hubble. bigger volume of space to find such “We’ve nailed something that is in- “These galaxies are very different galaxies,” said Castellano. credibly fascinating. These galaxies than the Milky Way or other big “These observations just make your would have had to have started galaxies we see around us today,” head explode. This is a whole new coming together maybe just 100 mil- said Treu. chapter in astronomy. It’s like an ar- lion years after the big bang. No- Illingworth emphasized the two chaeological dig, and suddenly you body expected that the dark ages bright galaxies found by these find a lost city or something you would have ended so early,” said teams have a lot of light. He said didn’t know about. It’s just stag- Garth Illingworth of the University one option is that they could have gering,” added Paola Santini, fourth of California at Santa Cruz, a mem- been very massive, with lots of low- author of the Castellano et al. ber of the Naidu/Oesch team. “The mass stars, like later galaxies. Alter- GLASS-JWST paper. primal universe would have been natively, they could be much less “While the distances of these early just one hundredth its current age. massive, consisting of far fewer ex- sources still need to be confirmed It’s a sliver of time in the 13.8 billion- traordinarily bright stars, known as with spectroscopy, their extreme year-old evolving cosmos.” Population III stars. Long theorized, brightnesses are a real puzzle, chal- Erica Nelson of the University of Col- they would be the first stars ever lenging our understanding of galaxy orado in Boulder, a member of the born, blazing at blistering tempera- formation,” noted Pascal Oesch at Naidu/Oesch team, noted that “our tures and made up only of primor- dial hydrogen and helium – before stars could later cook up heavier el- ements in their nuclear fusion fur- naces. No such extremely hot, pri- mordial stars are seen in the local universe. “Indeed, the farthest source is very compact, and its colors seem to indicate that its stellar pop- ulation is particularly devoid of heavy elements and could even con- tain some Population III stars. Only Webb spectra will tell,” said Adriano Fontana, second author of the Castellano et al. paper and a mem- ber of the GLASS-JWST team. Present Webb distance estimates to these two galaxies are based on measuring their infrared colors. Eventually, follow-up spectroscopy measurements showing how light has been stretched in the expanding universe will provide independent verification of these cosmic yardstick measurements. JANUARY-FEBRUARY 2023
22 ASTRO PUBLISHING Largest NEA detected in eight years by NOIRLab − Charles Blue A n international team using terior to the orbits of Earth and NEAs. One is a 1.5-kilometer-wide as- the Dark Energy Camera Venus. This is a notoriously challeng- teroid called 2022 AP7, which has an (DECam) mounted on the Víc- ing region for observations because orbit that may someday place it in tor M. Blanco 4-meter Telescope at asteroid hunters have to contend Earth’s path. The other asteroids, Cerro Tololo Inter-American Obser- with the glare of the Sun. called 2021 LJ4 and 2021 PH27, have vatory in Chile, a Program of NSF’s By taking advantage of the brief orbits that safely remain completely NOIRLab, has discovered three new yet favorable observing conditions interior to Earth’s orbit. Also of spe- near-Earth asteroids (NEAs) hiding in during twilight, however, the as- cial interest to astronomers and astro- the inner Solar System, the region in- tronomers found an elusive trio of physicists, 2021 PH27 is the closest JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 23 A rtist’s impression of an asteroid that orbits closer to the Sun than Earth’s orbit. [DOE/FNAL/ DECam/CTIO/NOIR- Lab/NSF/AURA/J. da Silva/Spaceengine] JANUARY-FEBRUARY 2023
24 ASTRO PUBLISHING T wilight observations with the US Department of Energy-fabricated Dark En- ble. DECam was funded by the US De- ergy Camera at Cerro Tololo Inter-American Observatory in Chile, a Program partment of Energy (DOE) and was of NSF’s NOIRLab, have enabled astronomers to spot three near-Earth asteroids built and tested at DOE’s Fermilab. (NEA) hiding in the glare of the Sun. These NEAs are part of an elusive population “Large areas of sky are required be- that lurks inside the orbits of Earth and Venus. One of the asteroids is the largest cause the inner asteroids are rare, and object that is potentially hazardous to Earth to be discovered in the last eight deep images are needed because as- years. [DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA/J. da Silva/Spaceengine, D. Mu- teroids are faint and you are fighting nizaga, T. Puzia (PUC), NASA, ESA/Hubble/L. Calçada/M. Kornmesser, N. Bartmann] the bright twilight sky near the Sun as well as the distorting effect of known asteroid to the Sun. As such, it Finding asteroids in the inner Solar Earth’s atmosphere,” said Sheppard. has the largest general-relativity ef- System is a daunting observational “DECam can cover large areas of sky fects of any object in our Solar System challenge. Astronomers have only to depths not achievable on smaller and during its orbit its surface gets two brief 10-minute windows each telescopes, allowing us to go deeper, hot enough to melt lead. night to survey this area and have to cover more sky, and probe the inner “Our twilight survey is scouring the contend with a bright background Solar System in ways never done be- area within the orbits of Earth and sky resulting from the Sun’s glare. Ad- fore.” As well as detecting asteroids Venus for asteroids,” said Scott S. ditionally, such observations are very that could potentially pose a threat to Sheppard, an astronomer at the Earth near to the horizon, meaning that as- Earth, this research is an important and Planets Laboratory of the tronomers have to observe through step toward understanding the distri- Carnegie Institution for Science and a thick layer of Earth’s atmosphere, bution of small bodies in our Solar the lead author of the paper describ- which can blur and distort their ob- System. Asteroids that are further ing this work. “So far we have found servations. from the Sun than Earth are easiest to two large near-Earth asteroids that Discovering these three new asteroids detect. Because of that these more- are about 1 kilometer across, a size despite these challenges was possible distant asteroids tend to dominate that we call planet killers.” thanks to the unique observing capa- current theoretical models of the as- “There are likely only a few NEAs bilities of DECam. The state-of-the-art teroid population. with similar sizes left to find, and instrument is one of the highest-per- Detecting these objects also allows as- these large undiscovered asteroids formance, wide-field CCD imagers in tronomers to understand how aster- likely have orbits that keep them in- the world, giving astronomers the oids are transported throughout the terior to the orbits of Earth and ability to capture large areas of sky inner Solar System and how gravita- Venus most of the time,” said Shep- with great sensitivity. Astronomers tional interactions and the heat of pard. “Only about 25 asteroids with refer to observations as ‘deep’ if they the Sun can contribute to their frag- orbits completely within Earth’s orbit capture faint objects. When hunting mentation. “Our DECam survey is one have been discovered to date because for asteroids inside Earth’s orbit, the of the largest and most sensitive of the difficulty of observing near the capability to capture both deep and searches ever performed for objects glare of the Sun.” wide-field observations is indispensa- within Earth’s orbit and near to Venus’s orbit,” said Sheppard. “This is a unique chance to understand what types of objects are lurking in the inner Solar System.” “After ten years of remarkable serv- ice, DECam continues to yield impor- tant scientific discoveries while at the same time contributing to planetary defense, a crucial service that benefits all humanity,” said Chris Davis, NSF Program Director for NOIRLab. DECam was originally built to carry out the Dark Energy Survey, which was conducted by the DOE and the US National Science Foundation be- tween 2013 and 2019. JANUARY-FEBRUARY 2023
www.newmoontelescopes.com [email protected]
26 ASTRO PUBLISHING Kilonovae, a target for the Roman Space Telescope by NASA/ESA Claire Blome & Christine Pulliam W hat happens when the The astronomical community cap- densest, most massive tured one of these remarkable kilo- stars – that are also super nova events in 2017. Scientists at the small – collide? They send out bril- National Science Foundation’s Laser liant explosions known as kilonovae. Interferometer Gravitational-Wave Think of these events as the uni- Observatory (LIGO) detected the col- verse’s natural fireworks. Theorists lision of two neutron stars first with suspect they periodically occur all gravitational waves – ripples in across the cosmos – both near and space-time. Almost simultaneously, far. Scientists will soon have an ad- NASA’s Fermi Gamma-ray Space Tel- ditional observatory to help follow escope detected high-energy light. up on and even scout these remark- NASA quickly pivoted to observe the able events: NASA’s Nancy Grace event with a broader fleet of tele- Roman Space Telescope, which is set scopes, and captured the fading to launch by May 2027. glow of the blast’s expanding debris The key actors in kilonovae are neu- in a series of images. tron stars, the central cores of stars But the players in this example col- that collapsed under gravity during lided practically in our “backyard,” supernova explosions. They each at least in astronomical terms. They have a mass similar to the Sun, but lie only 130 million light-years away. are only about 6 miles (10 kilome- There must be more kilonovae – and ters) in diameter. And when they many that are farther flung – dot- collide, they send out debris moving ting our ever-active universe. near the speed of light. These explo- “We don’t yet know the rate of sions are also thought to forge these events,” said Daniel M. Scolnic, heavy elements, like gold, platinum, an assistant professor of physics at and strontium (which gives actual Duke University in Durham, North fireworks their stunning reds). Kilo- Carolina. Scolnic led a study that es- novae shoot those elements across timates the number of kilonovae space, potentially allowing them to that could be discovered by past, end up in rocks forming the crust of present, and future observatories in- terrestrial planets like Earth. cluding Roman. “Is the single kilo- JANUARY-FEBRUARY 2023
F ollowing its launch no later than May 2027, NASA’s Roman Space Telescope will survey the same areas of the sky every few days. Researchers will mine these data to identify kilonovae – explosions that happen when two neutron stars or a neutron star and a black hole collide and merge. When these collisions happen, a fraction of the resulting debris is ejected as jets, which move near the speed of light. The remaining debris produces hot, glowing, neutron-rich clouds that forge heavy elements, like gold and platinum. Roman’s extensive data will help astronomers better identify how often these events occur, how much energy they give off, and how near or far they are. [Artwork: NASA, Joseph Olmsted (STScI)] JANUARY-FEBRUARY 2023
28 ASTRO PUBLISHING O n 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory years to reach Earth,” explained Eve (LIGO) and the Virgo Interferometerboth detected gravitational waves from Chase, a postdoctoral researcher at the collision between two neutron stars. Within 12 hours observatories had iden- Los Alamos National Laboratory in tified the source of the event within the lenticular galaxy NGC 4993, shown in this Los Alamos, New Mexico. image gathered with the NASA/ESA Hubble Space Telescope. The associated stel- Chase led a more recent study that lar flare, a kilonova, is clearly visible in the Hubble observations. Hubble observed simulated how differences in kilono- the kilonova gradually fading over the course of six days. [NASA and ESA. Ack.: N. vae ejecta can vary what we expect Tanvir (U. Leicester), A. Levan (U. Warwick), and A. Fruchter and O. Fox (STScI)] to observe from observatories in- cluding Roman. nova we identified typical? How larger than the Hubble Space Tele- There’s a second benefit to near-in- bright are these explosions? What scope’s infrared view – not as vast as frared light: It provides more time to types of galaxies do they occur in?” LIGO’s, but huge for a telescope that observe these short-lived bursts. Existing telescopes can’t cover wide takes images. Its cadence will allow Shorter wavelengths of light, like ul- enough areas or observe deeply researchers to spot when objects on traviolet and visible, disappear from enough to find more distant ex- the sky brighten or dim, whether view in a day or two. Near-infrared amples, but that will change with nearby or very far away. light can be gathered for a week or Roman. Roman will provide researchers a more. Researchers have been simu- At this stage, LIGO leads the pack in powerful tool for observing ex- lating the data to see how this will identifying neutron star mergers. It tremely distant kilonovae. This is work. “For a subset of simulated can detect gravitational waves in all due to the expansion of space. Light kilonovae, Roman would be able to areas of the sky, but some of the that left stars billions of years ago is observe some more than two weeks most distant collisions may be too stretched into longer, redder wave- after the neutron star merger oc- weak to be identified. Roman is set lengths, known as infrared light, curred,” Chase added. “It will be an to join LIGO’s search, offering com- over time. Since Roman specializes in excellent tool for looking at kilono- plementary qualities that help “fill capturing near-infrared light, it will vae that are very far away.” out” the team. Roman is a survey detect light from very distant ob- Soon, researchers will know far telescope that will repeatedly scan jects. How distant? “Roman will be more about where kilonovae occur, the same areas of the sky. Plus, able to see some kilonovae whose and how often these explosions Roman’s field of view is 200 times light has traveled about 7 billion occur in the history of the universe. Were those that occurred earlier dif- ferent in some way? “Roman will allow the astronomy community to begin conducting population studies along with a slew of new analyses on the physics of these explosions,” Scolnic said. A survey telescope offers enormous possibility – and also a ton of data that will require precise machine learning. Astronomers are meeting this challenge by writing code to au- tomate these searches. Ultimately, Roman’s massive data sets will help researchers unravel perhaps the greatest mysteries about kilonovae to date: What happens after two neutron stars collide? Does it pro- duce a single neutron star, a black hole, or something else entirely? With Roman, we will gather the sta- tistics researchers need to make sub- stantial breakthroughs. JANUARY-FEBRUARY 2023
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30 ASTRO PUBLISHING Vela SNR imaged by the VLT Survey Telescope by ESO - Juan Carlos Muñoz Mateos JANUARY-FEBRUARY 2023
A spooky spider web, magical T his panel dragons or wispy trails of shows the ghosts? What do you see in process of going this image of the Vela supernova from the raw remnant? This beautiful tapestry of data captured by colours shows the ghostly remains of a telescope to a a gigantic star, and was captured stunning astro- here in incredible detail with the nomical image VLT Survey Telescope, hosted at the like the one European Southern Observatory’s featured here, (ESO’s) Paranal site in Chile. showing the The wispy structure of pink and or- Vela supernova ange clouds is all that remains of a remnant as seen massive star that ended its life in a with the VLT powerful explosion around 11,000 Survey Telescope years ago. When the most massive (VST). [ESO/M stars reach the end of their life, they Kornmesser, often go out with a bang, in an out- VPHAS+ team. burst called a supernova. Ack.: Cambridge These explosions cause shock waves Astronomical that move through the surrounding Survey Unit] gas, compressing it and creating in- tricate thread-like structures. The the spectacular filaments that we energy released heats the gaseous observe here. What remains of the tendrils, making them shine brightly, star is an ultra-dense ball in which as seen in this image. the protons and electrons are In this 554-million-pixel image, we forced together into neutrons — a get an extremely detailed view of neutron star. The neutron star in the the Vela supernova remnant, named Vela remnant, placed slightly out- after the southern constellation Vela side of this image to the upper left, (The Sails). You could fit nine full happens to be a pulsar that spins on Moons in this entire image, and the its own axis at an incredible speed whole cloud is even larger. At only of more than 10 times per second. 800 light-years away from Earth, this This image is a mosaic of observa- dramatic supernova remnant is one tions taken with the wide-field cam- of the closest known to us. era OmegaCAM at the VLT Survey As it exploded, the outermost layers Telescope (VST), hosted at ESO’s of the progenitor star were ejected Paranal Observatory in Chile. into the surrounding gas, producing The 268-million-pixel camera can take images through several filters that let through light of different colours. In this particular image of the Vela remnant, four different fil- ters were used, represented here by a combination of magenta, blue, green and red. The VST is owned by The National Institute for Astrophysics in Italy, INAF, and with its 2.6-metre mirror it is one of the largest telescopes dedicated to surveying the night sky in visible light. This image is an example from such a survey: the VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+). For over seven years, this survey has mapped a considerable portion of our home galaxy, allow- ing astronomers to better under- stand how stars form, evolve and eventually die. JANUARY-FEBRUARY 2023
32 ASTRO PUBLISHING WASP-39 b’s atmosphere as never seen before by IAC − Science Communication and Culture Unit W ebb has produced a mo- oration involving research staff from Webb’s exquisitely sensitive instru- lecular and chemical por- the Instituto de Astrofísica de Ca- ments have provided a profile of trait of the atmospheric narias (IAC). WASP-39 b’s atmospheric con- constituents of exoplanet WASP-39 WASP-39 b is a planet unlike any in stituents and identified a plethora of b, a Saturn-sized behemoth that our solar system. It is a so-called “hot contents, including water, sulfur orbit a star some 700 light-years Saturn”, a planet about as massive as dioxide, carbon monoxide, sodium away. The observations provide a full Saturn but in an orbit tighter than and potassium. The data also sug- menu of atoms and molecules, and Mercury. This exoplanet was one of gest the presence of clouds that may even signs of active chemistry and the first examined by Webb when it be fragmented rather than forming clouds. The suit of discoveries is de- began regular science operations. a single, uniform mantle over the tailed in a set of five scientific papers The results have excited the exo- planet. “We observed the exoplanet produced by an international collab- planet science community. with multiple instruments that, to- JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 33 gether, provide a broad the University of Oxford in the swath of the infrared United Kingdom and lead author of spectrum and a panoply the paper explaining the origin of of chemical fingerprints sulfur dioxide in WASP-39 b’s atmos- inaccessible until [this phere. mission],” said Natalie To see light from WASP-39 b, Webb tracked the planet as it passed in Batalha, an astronomer front of its star, allowing some of at the University of the star’s light to filter through the California, Santa Cruz, planet’s atmosphere. Different types who contributed to of chemicals in the atmosphere ab- and helped coordinate sorb different colors of the starlight the new research. “Data spectrum, so the colors that are miss- like these are a game ing tell astronomers which mole- changer.” cules are present. By viewing the Among the unprece- universe in infrared light, Webb can dented revelations is the pick up chemical fingerprints that first detection in an exo- can’t be detected in visible light. planet atmosphere of Other atmospheric constituents de- sulfur dioxide (SO2), a mol- tected by the Webb telescope in- ecule produced from chem- clude sodium (Na), potassium (K), ical reactions triggered by and water vapor (H2O), confirming high-energy light from the previous space- and ground-based planet’s parent star. On Earth, telescope observations as well as the protective ozone layer in finding additional fingerprints of the upper atmosphere is cre- water, at these longer wavelengths, ated in a similar way. that haven’t been seen before. “This is the first time we see con- Webb also saw carbon dioxide (CO2) crete evidence of photochemistry – at higher resolution, providing twice chemical reactions initiated by ener- as much data as reported from its getic stellar light – on exoplanets,” previous observations. said Shang-Min Tsai, a researcher at T his illustration shows what exo- planet WASP-39 b could look like, based on current understanding of the planet. WASP-39 b is a hot, puffy gas giant with a mass 0.28 times Jupiter (0.94 times Saturn) and a diameter 1.3 times greater than Jupiter, orbiting just 0.0486 astro- nomical units from its star. The star, WASP-39, is fractionally smaller and less massive than the Sun. Because it is so close to its star, WASP-39 b is very hot and is likely to be tidally locked, with one side facing the star at all times. [NASA, ESA, CSA, Joseph Olmsted (STScI)] JANUARY-FEBRUARY 2023
34 ASTRO PUBLISHING T he atmospheric com- position of the hot gas giant exoplanet WASP-39 b has been re- vealed by NASA’s James Webb Space Telescope. This graphic shows four transmission spectra from three of Webb’s instruments operated in four instrument modes. All are plotted on a common scale extend- ing from 0.5 to 5.5 mi- crons. A transmission spectrum is made by comparing starlight fil- tered through a planet’s atmosphere as it moves in front of the star, to the unfiltered starlight detected when the planet is beside the star. Each of the data points (white circles) on these graphs represents the amount of a specific wavelength of light that is blocked by the planet and absorbed by its at- mosphere. Wavelengths that are preferentially absorbed by the atmos- phere appear as peaks in the transmission spectrum. The blue line is a best-fit model that takes into account the data, the known proper- ties of WASP-39 b and its star (e.g., size, mass, temperature), and as- sumed characteristics of the atmosphere. At upper left, data from NIRISS shows finger- prints of potassium (K), water (H2O), and carbon monoxide (CO). At upper right, data from NIRCam shows a prominent water signature. At lower left, data from NIRSpec indicates water, sulfur dioxide (SO2), carbon dioxide (CO2), and carbon monoxide (CO). At lower right, additional NIRSpec data reveals all of these molecules as well as sodium (Na). [NASA, ESA, CSA, Joseph Olmsted (STScI)] Meanwhile, carbon monoxide (CO) levels. To capture this broad spec- modes. “We had predicted what [the was detected, but obvious signa- trum of WASP-39 b’s atmosphere, an telescope] would show us, but it was tures of both methane (CH4) and hy- international team numbering in the more precise, more diverse, and drogen sulfide (H2S) were absent hundreds independently analyzed more beautiful than I actually be- from the Webb data. If present, data from four of the Webb tele- lieved it would be,” said Hannah these molecules occur at very low scope’s finely calibrated instrument Wakeford, an astrophysicist at the JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 35 University of Bristol. Having such a perhaps others – formed out of the cated that the planet complete roster of chemical ingredi- disk of gas and dust surrounding the presumably experi- ents in an exoplanet atmosphere parent star in its younger years. enced significant ac- also gives scientists a glimpse of the WASP-39 b’s chemical inventory sug- cretion of planetes- abundance of different elements in gests a history of smashups and imals that can deliver relation to each other, such as car- mergers of smaller bodies called [these ingredients] to bon-to-oxygen or potassium-to-oxy- planetesimals to create an eventual the atmosphere,” said gen ratios. That, in turn, provides goliath of a planet. “The abundance Kazumasa Ohno, a insight into how this planet – and of sulfur [relative to] hydrogen indi- UC Santa Cruz exo- planet researcher who worked on Webb data. “The data also indicates that the oxy- gen is a lot more abundant than the carbon in the atmos- phere. This potentially indicates that WASP- 39 b originally formed far away from the cen- tral star.” In so precisely parsing an exoplanet atmos- phere, the Webb tele- scope’s instruments performed well be- yond scientists’ expec- tations – and promise a new phase of explo- ration among the broad variety of exo- planets in the galaxy. “These results are a confirmation of the ability of the JWST in- struments to probe the atmospheres of all types of exoplanets, including small and rocky worlds,” says Enric Pallé, IAC re- searcher who partici- pated in the study. “We are going to be able to see the big picture of exoplanet atmos- pheres,” said Laura Flagg, a re- searcher at Cornell University and a member of the international team. “It is incredibly exciting to know that everything is going to be rewritten. That is one of the best parts of being a scientist.” JANUARY-FEBRUARY 2023
36 ASTRO PUBLISHING A new view of the dark cloud L1527 by NASA/ESA/CSA Matthew Brown Christine Pulliam NASA’s James Webb Space Tele- dust, the less blue light is able to es- clump of gas somewhere between scope has revealed the once- cape, creating pockets of orange. 20 and 40% the mass of our Sun. As hidden features of the proto- Webb also reveals filaments of mo- the protostar continues to gather star within the dark cloud L1527, lecular hydrogen that have been mass, its core gradually compresses providing insight into the begin- shocked as the protostar ejects ma- and gets closer to stable nuclear fu- nings of a new star. These blazing terial away from it. Shocks and tur- sion. The scene shown in this image clouds within the Taurus star-form- bulence inhibit the formation of reveals L1527 doing just that. ing region are only visible in in- new stars, which would otherwise The surrounding molecular cloud is frared light, making it an ideal form all throughout the cloud. As a made up of dense dust and gas target for Webb’s Near-Infrared result, the protostar dominates the being drawn to the center, where Camera (NIRCam). space, taking much of the material the protostar resides. As the mate- The protostar itself is hidden from for itself. rial falls in, it spirals around the cen- view within the “neck” of this hour- Despite the chaos that L1527 causes, ter. This creates a dense disk of glass shape. An edge-on protoplan- it’s only about 100,000 years old - a material, known as an accretion etary disk is seen as a dark line across relatively young body. Given its age disk, which feeds material to the the middle of the neck. Light from and its brightness in far-infrared protostar. As it gains more mass and the protostar leaks above and below light as observed by missions like compresses further, the tempera- this disk, illuminating cavities within the Infrared Astronomical Satellite, ture of its core will rise, eventually the surrounding gas and dust. L1527 is considered a class 0 proto- reaching the threshold for nuclear The region’s most prevalent fea- star, the earliest stage of star forma- fusion to begin. tures, the clouds colored blue and tion. Protostars like these, which are The disk, seen in the image as a dark orange in this representative-color still cocooned in a dark cloud of dust band in front of the bright center, is infrared image, outline cavities cre- and gas, have a long way to go be- about the size of our solar system. ated as material shoots away from fore they become full-fledged stars. Given the density, it’s not unusual the protostar and collides with sur- L1527 doesn’t generate its own en- for much of this material to clump rounding matter. The colors them- ergy through nuclear fusion of hy- together - the beginnings of plan- selves are due to layers of dust drogen yet, an essential character- ets. Ultimately, this view of L1527 between Webb and the clouds. The istic of stars. Its shape, while mostly provides a window into what our blue areas are where the dust is spherical, is also unstable, taking Sun and solar system looked like in thinnest. The thicker the layer of the form of a small, hot, and puffy their infancy. JANUARY-FEBRUARY 2023
T he protostar within the dark cloud L1527, shown in this image from NASA’s James Webb Space Telescope Near-Infrared Camera (NIRCam), is embedded within a cloud of material feeding its growth. Ejections from the star have cleared out cavities above and below it, whose boundaries glow orange and blue in this infrared view. The upper central region displays bubble-like shapes due to stellar “burps,” or spo- radic ejections. Webb also detects fil- aments made of molecular hydrogen that has been shocked by past stellar ejections. The edges of the cavities at upper left and lower right appear straight, while the boundaries at upper right and lower left are curved. The region at lower right ap- pears blue, as there’s less dust be- tween it and Webb than the orange regions above it. [NASA, ESA, CSA, STScI − Joseph DePasquale (STScI), Alyssa Pagan (STScI), Anton M. Koekemoer (STScI)]
38 ASTRO PUBLISHING The Cone Nebula as seen by the VLT by ESO - Juan Carlos Muñoz Mateos For the past 60 years the Euro- T his image from the Digitized Sky Survey (DSS) shows the region of the sky pean Southern Observatory around the Cone Nebula. The nebulous area at the centre of the image is (ESO) has been enabling scien- NGC 2264, an area of the sky that includes the Christmas Tree star cluster and tists worldwide to discover the se- the Cone Nebula below it (at the very centre of the frame). [ESO/Digitized Sky crets of the Universe. We mark this Survey 2. Acknowledgement: D. De Martin] milestone by bringing you a spec- tacular new image of a star factory, strategic partners, ESO brings to- ESO released this extraordinary im- the Cone Nebula, taken with ESO’s gether scientists and engineers from age of the Cone Nebula, captured Very Large Telescope (VLT). across the globe to develop and op- with one of ESO's telescopes and se- On 5 October 1962 five countries erate advanced ground-based ob- lected by the observatory staff. signed the convention to create ESO. servatories in Chile that enable The image is part of a campaign Now, six decades later and sup- breakthrough astronomical discov- which celebrated ESO’s 60th anniver- ported by 16 Member States and eries. To mark its 60th anniversary, sary in late 2022, both on social JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 39 when massive, newly formed bright blue stars give off stellar winds and intense ultraviolet radiation that blow away the material from their vicinity. As this material is pushed away, the gas and dust further away from the young stars gets com- pressed into dense, dark and tall pillar-like shapes. This process helps create the dark Cone Nebula, pointing away from the brilliant stars in NGC 2264. In this image, ob- tained with the FOcal Reducer and low dispersion Spectro- graph 2 (FORS2) on ESO’s VLT in Chile, hydrogen gas is repre- sented in blue and sulphur gas in red. The use of these filters makes the otherwise bright blue stars, that indicate the re- cent star formation, appear al- most golden, contrasting with the dark cone like sparklers. This image is just one example of the many stunning and awe- inspiring observations ESO tel- escopes have made in the past 60 years. While this one was obtained for outreach pur- poses, the overwhelming ma- T he Cone Nebula is part of a star-forming region of space, NGC 2264, about 2500 jority of ESO’s telescope time is light-years away. Its pillar-like appearance is a perfect example of the shapes that dedicated to scientific observa- can develop in giant clouds of cold molecular gas and dust, known for creating new tions that have allowed us to stars. This dramatic new view of the nebula was captured with the FOcal Reducer and capture the first image of an low dispersion Spectrograph 2 (FORS2) instrument on ESO’s Very Large Telescope exoplanet, study the black hole (VLT), and released on the occasion of ESO’s 60th anniversary. [ESO] at the centre of our home galaxy, and find proof that the channels and with local events in years away, the Cone Nebula is rela- expansion of our Universe is acceler- ESO Member States and beyond. tively close to Earth, making it a ating. Building on our 60 years of ex- In the above image, we see centre- well-studied object. But this view is perience in astronomy development, stage the seven-light-year-long pil- more dramatic than any obtained discovery and cooperation, ESO con- lar of the Cone Nebula, which is before, as it showcases the nebula’s tinues to chart new territory for as- part of the larger star-forming re- dark and impenetrable cloudy ap- tronomy, technology and interna- gion NGC 2264 and was discovered pearance in a way that makes it re- tional collaboration. With our cur- in the late 18th century by as- semble a mythological creature. The rent facilities and ESO’s upcoming tronomer William Herschel. In the Cone Nebula is a perfect example of Extremely Large Telescope (ELT), we sky, we find this horn-shaped neb- the pillar-like shapes that develop in will keep on addressing humanity’s ula in the constellation Monoceros the giant clouds of cold molecular biggest questions about the Uni- (The Unicorn), a surprisingly fitting gas and dust, known for creating verse and enabling unimaginable name. Located less than 2500 light- new stars. This type of pillar arises discoveries. JANUARY-FEBRUARY 2023
40 ASTRO PUBLISHING Astronomers discover closest black hole to Earth by NOIRLab − Charles Blue Black holes are the most ex- Gaia BH1. This dormant black hole is claimed detections of systems like treme objects in the Universe. about 10 times more massive than this, almost all these discoveries Supermassive versions of these the Sun and is located about 1600 have subsequently been refuted. unimaginably dense objects likely light-years away in the constellation This is the first unambiguous detec- reside at the centers of all large Ophiuchus, making it three times tion of a Sun-like star in a wide orbit galaxies. Stellar-mass black holes — closer to Earth than the previous around a stellar-mass black hole in which weigh approximately five to record holder, an X-ray binary in the our Galaxy.” 100 times the mass of the Sun — are constellation of Monoceros. The Though there are likely millions of much more common, with an esti- new discovery was made possible by stellar-mass black holes roaming the mated 100 million in the Milky Way making exquisite observations of Milky Way Galaxy, those few that alone. Only a handful have been the motion of the black hole’s com- have been detected were uncovered confirmed to date, however, and panion, a Sun-like star that orbits by their energetic interactions with nearly all of these are ‘active’ – the black hole at about the same dis- a companion star. As material from meaning they shine brightly in X- tance as the Earth orbits the Sun. a nearby star spirals in toward the rays as they consume material from “Take the Solar System, put a black black hole, it becomes superheated a nearby stellar companion, unlike hole where the Sun is, and the Sun and generates powerful X-rays and dormant black holes which do not. where the Earth is, and you get this jets of material. If a black hole is not Astronomers using the Gemini system,” explained Kareem El-Badry, actively feeding (i.e., it is dormant) North telescope on Hawai’i, one of an astrophysicist at the Center for it simply blends in with its surround- the twin telescopes of the Interna- Astrophysics | Harvard & Smithson- ings. tional Gemini Observatory, operated ian and the Max Planck Institute for “I’ve been searching for dormant by NSF’s NOIRLab, have discovered Astronomy, and the lead author of black holes for the last four years the closest black hole to Earth, the paper describing this discov- using a wide range of datasets and which the researchers have dubbed ery. “While there have been many methods,” said El-Badry. “My previ- JANUARY-FEBRUARY 2023
A stronomers using the International Gemini Observatory, operated by NSF’s NOIRLab, have discovered the closest-known black hole to Earth. This is the first unambiguous detection of a dormant stellar-mass black hole in the Milky Way. Its close proximity to Earth, a mere 1600 light-years away, offers an intriguing target of study to advance our understanding of the evolution of binary systems. [International Gem- ini Observatory/NOIRLab/NSF/AURA/J. da Silva/Spaceengine/M. Zamani] JANUARY-FEBRUARY 2023
42 ASTRO PUBLISHING ous attempts — as well as those of observations. “When we had the gen-burning, main-sequence star others — turned up a menagerie of first indications that the system con- like our Sun. binary systems that masquerade as tained a black hole, we only had one It is not at all clear how the solar- black holes, but this is the first time week before the two objects were at mass star could have survived that the search has borne fruit.” the closest separation in their orbits. episode, ending up as an apparently The team originally identified the Measurements at this point are es- normal star, as the observations of system as potentially hosting a black sential to make accurate mass esti- the black hole binary indicate. The- hole by analyzing data from the Eu- mates in a binary system,” said oretical models that do allow for ropean Space Agency’s Gaia space- El-Badry. “Gemini’s ability to provide survival all predict that the solar- craft. Gaia captured the minute observations on a short timescale mass star should have ended up on irregularities in the star’s motion was critical to the project’s success. a much tighter orbit than what is ac- caused by the gravity of an unseen If we’d missed that narrow window, tually observed. massive object. To ex- This could indicate that plore the system in there are important more detail, El-Badry gaps in our under- and his team turned to standing of how black the Gemini Multi-Ob- holes form and evolve ject Spectrograph in- in binary systems, and strument on Gemini also suggests the exis- North, which meas- tence of an as-yet-un- ured the velocity of explored population of the companion star as dormant black holes in it orbited the black binaries. “It is interest- hole and provided pre- ing that this system is cise measurement of not easily accommo- its orbital period. The dated by standard bi- Gemini follow-up ob- nary evolution models,” servations were crucial T his video summarizes the discovery of the closest black hole to concluded El-Badry. “It to constraining the or- Earth. [nternational Gemini Observatory/NOIRLab/NSF/AURA/ poses many questions bital motion and J.Pollard/J. da Silva/Spaceengine/ M. Zamani/ T. Müller (MPIA), Pan- about how this binary hence masses of the STARRS DR1 (K. C. Chambers et al. 2016), ESA/Gaia/DPAC (CC BY-SA system was formed, as two components in the 3.0 IGO)/ NASA’s Scientific Visualization Studio/ Walt Feimer (HTSI)/ well as how many of binary system, allow- Michael McClare (HTSI)/Dana Berry (Skyworks Digital)/ Michael Mc- these dormant black ing the team to iden- Clare (HTSI), N. Bartmann] holes there are out tify the central body as there.” a black hole roughly 10 times as we would have had to wait another “As part of a network of space- and massive as our Sun. “Our Gemini fol- year.” Astronomers’ current models ground-based observatories, Gemini low-up observations confirmed be- of the evolution of binary systems North has not only provided strong yond reasonable doubt that the are hard-pressed to explain how the evidence for the nearest black hole binary contains a normal star and at peculiar configuration of Gaia BH1 to date but also the first pristine least one dormant black hole,” elab- system could have arisen. Specifi- black hole system, uncluttered by orated El-Badry. “We could find no cally, the progenitor star that later the usual hot gas interacting with plausible astrophysical scenario that turned into the newly detected the black hole,” said NSF Gemini can explain the observed orbit of black hole would have been at least Program Officer Martin Still. “While the system that doesn’t involve at 20 times as massive as our Sun. This this potentially augurs future dis- least one black hole.” The team re- means it would have lived only a coveries of the predicted dormant lied not only on Gemini North’s su- few million years. If both stars black hole population in our Galaxy, perb observational capabilities but formed at the same time, this mas- the observations also leave a mys- also on Gemini’s ability to provide sive star would have quickly turned tery to be solved — despite a shared data on a tight deadline, as the into a supergiant, puffing up and history with its exotic neighbor, why team had only a short window in engulfing the other star before it is the companion star in this binary which to perform their follow-up had time to become a proper, hydro- system so normal?” JANUARY-FEBRUARY 2023
Science in School aims to promote inspir- ing science teaching by encouraging communica- tion between teachers, scientists, and everyone else involved in European sci- ence education. Science in School is published by EIROforum, a collaboration between eight European intergovernmen- tal scientific research organisations, of which ESO is a member. The journal addresses science teaching both across Europe and across disciplines: highlighting the best in teaching and cutting-edge research. Read more about Science in School at: http://www.scienceinschool.org/
44 ASTRO PUBLISHING Three faces of evolving supernova in early Universe by NASA/ESA Bethany Downer T hree different moments in a a fifth of its current age of 13.8 bil- observation was possible thanks to far-off supernova explosion lion years. This is the first detailed the phenomenon called gravita- were captured in a single look at a supernova at such an early tional lensing, as first predicted by snapshot by the NASA/ESA Hubble time in the Universe’s evolution. The Einstein’s general theory of relativ- Space Telescope. The progenitor star data could help scientists learn more ity. In this case, the light took three exploded more than 11 billion years about the formation of stars and different paths through the cosmic ago, when the Universe was less than galaxies in the early Universe. This lens of the massive galaxy cluster F ive panels are shown. The larger left panel shows the portion of the galaxy cluster Abell 370 where the multiple images of the supernova appeared, which is shown in four panels labelled A through D on the right. These panels show the loca- tions of the multiply imaged host galaxy after a supernova faded and the different colours of the cooling supernova at three different stages in its evolution. [NASA, ESA, STScI, Wenlei Chen (UMN), Patrick Kelly (UMN), Hubble Frontier Fields] JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 45 the fading super- nova’s rapid change of colour, which in- dicates its changing temperature. The bluer the colour, the hotter the super- nova is. The earliest phase captured ap- pears blue. As the su- pernova cooled its light turned redder. This is also the first time astronomers have been able to measure the size of a dying star in the early Universe. They did this by observing the supernova’s bright- ness and rate of cool- ing, both of which depend on the size of the progenitor star. Hubble’s observa- tions show that the red supergiant whose supernova explosion the researchers dis- covered had a radius about 500 times larger than the Sun. An international team of astronomers T hrough the phenomenon of gravitational lensing, the NASA/ESA Hubble Space Telescope cap- found this supernova tured three different moments in the explosion of a very far-off supernova—all in one picture! by sifting through the Hubble data In this case, the immense gravity of the galaxy cluster Abell 370 acted as a cosmic lens, bending archives, looking for and magnifying the light from the more distant supernova located behind the cluster. The warping transient events. also produced multiple images of the explosion over different time periods that all arrived at Hub- ble simultaneously. The top box shows a portion of Abell 370. The box-within-the-box marks the The team also has area where the distant supernova was multiply lensed. The bottom image is a magnified version time planned for the of this area with the light paths marked for the three images of the supernova. The right side of NASA/ESA/CSA James the bottom image shows the distant galaxy in which the supernova exploded. The lines show how Webb Space Tele- the light travelled through the gravitational lens, with some of the light taking longer routes scope to observe across “valleys” of warped space. The warping produced three images of the explosion over differ- even more distant su- ent time periods that all arrived at Hubble simultaneously. [NASA, ESA, A. Pagan (STScI)] pernovae. They hope to contribute to a cat- Abell 370, bending and magnifying rived at Hubble (on the same day in alogue of very far-off supernovae to the light from the more distant su- December 2010), the supernova ap- help astronomers understand if the pernova located behind the cluster. peared at three different stages of stars that existed many billions of The three paths were of three dif- evolution. years ago are different from those ferent lengths, so when the light ar- The Hubble exposure also captured in the nearby Universe. JANUARY-FEBRUARY 2023
46 ASTRO PUBLISHING Most distant detection of a black hole swallowing a star by ESO - Juan Carlos Muñoz Mateos Stars that wander too close to a of short-lived, often extreme, events prompted astronomers to trigger black hole are ripped apart by that could then be studied in much several telescopes from across the the incredible tidal forces of greater detail by telescopes such as globe to observe the mystery source the black hole in what is known as a ESO’s VLT in Chile. “We developed in more detail. This included ESO’s tidal disruption event (TDE). Approx- an open-source data pipeline to VLT, which quickly observed this new imately 1% of these cause jets of store and mine important informa- event with the X-shooter instru- plasma and radiation to be ejected tion from the ZTF survey and alert ment. The VLT data placed the from the poles of the rotating black us about atypical events in real source at an unprecedented dis- hole. In 1971, the black hole pioneer time,” explains Igor Andreoni, an as- tance for these events: the light pro- John Wheeler introduced the con- tronomer at the University of Mary- duced from AT2022cmc began its cept of jetted-TDEs as “a tube of land in the US who co-led the paper journey when the universe was toothpaste gripped tight about its published today in Nature together about one third of its current age. A middle,” causing the system to with Michael Coughlin from the Uni- wide variety of light, from high en- “squirt matter out of both ends.” versity of Minnesota. ergy gamma rays to radio waves, “We have only seen a handful of In February of this year the ZTF de- was collected by 21 telescopes these jetted-TDEs and they remain tected a new source of visible light. around the world. The team com- very exotic and poorly understood The event, named AT2022cmc, was pared these data with different events,” says Nial Tanvir from the reminiscent of a gamma ray burst — kinds of known events, from collaps- University of Leicester in the UK, the most powerful source of light ing stars to kilonovae. But the only who led the observations to deter- in the Universe. The prospect of scenario that matched the data was mine the object’s distance with the witnessing this rare phenomenon a rare jetted-TDE pointing towards VLT. Astronomers are thus constantly hunting for these extreme events to T his artist’s impression illustrates how it might look when a star approaches understand how the jets are actually too close to a black hole, where the star is squeezed by the intense gravita- created and why such a small frac- tional pull of the black hole. Some of the star’s material gets pulled in and tion of TDEs produce them. swirls around the black hole forming the disc that can be seen in this image. In As part of this quest many tele- rare cases, such as this one, jets of matter and radiation are shot out from the scopes, including the Zwicky Tran- poles of the black hole. In the case of the AT2022cmc event, evidence of the sient Facility (ZTF) in the US, jets was detected by various telescopes including the VLT, which determined repeatedly survey the sky for signs this was the most distant example of such an event. [ESO/M.Kornmesser] JANUARY-FEBRUARY 2023
us. Giorgos Leloudas, an astronomer AT2022cmc to be the most distant an optical survey,” says Daniel Per- at DTU Space in Denmark and co-au- TDE to have ever been discovered, ley, an astronomer at Liverpool John thor of this study, explains that “be- but this is not the only record-break- Moores University in the UK and co- cause the relativistic jet is pointing ing aspect of this object. “Until now, author of the study. This demon- at us, it makes the event much the small number of jetted-TDEs strates a new way of detecting brighter than it would otherwise ap- that are known were initially de- jetted-TDEs, allowing further study pear, and visible over a broader span tected using high energy gamma- of these rare events and probing of the electromagnetic spectrum.” ray and X-ray telescopes, but this of the extreme environments sur- The VLT distance measurement found was the first discovery of one during rounding black holes. JANUARY-FEBRUARY 2023
48 ASTRO PUBLISHING ‘Marshmallow’ world orbiting a cool red dwarf star by NOIRLab - Charles Blue A stronomers using the WIYN ever detected around a red dwarf and erupt with powerful flares capa- 3.5-meter Telescope at Kitt star and is estimated to have an av- ble of stripping a planet of its at- Peak National Observatory in erage density akin to that of a mosphere, making this star system a Arizona, a Program of NSF’s NOIR- marshmallow. seemingly inhospitable location to Lab, have observed an unusual Red dwarf stars are the smallest and form such a gossamer planet. “Giant Jupiter-like planet in orbit around a dimmest members of so-called main- planets around red dwarf stars have cool red dwarf star. Located approx- sequence stars — stars that convert traditionally been thought to be imately 580 light-years from Earth in hydrogen into helium in their cores hard to form,” says Shubham Kan- the constellation of Auriga the Char- at a steady rate. Though “cool” odia, a researcher at Carnegie In- ioteer, this planet, identified as TOI- compared to stars like our Sun, red stitution for Science’s Earth and 3757 b, is the lowest-density planet dwarf stars can be extremely active Planets Laboratory and first author JANUARY-FEBRUARY 2023
ASTRO PUBLISHING 49 A gas giant exoplanet (left) with the density of a marshmallow has been detected in orbit around a cool red dwarf star (right) by the NASA-funded NEID radial-velocity instru- ment on the 3.5-meter WIYN Telescope at Kitt Peak National Observatory, a Program of NSF’s NOIRLab. The planet, named TOI-3757 b, is the fluffiest gas giant planet ever discovered around this type of star. [NOIRLab/NSF/ AURA/J. da Silva/Space- engine/M. Zamani] JANUARY-FEBRUARY 2023
50 ASTRO PUBLISHING on a paper published in The Astro- T his video presents the discovery of a new Jovian-sized planet, TOI-3757 b, nomical Journal. “So far this has the lowest-density transiting planet known to orbit an M dwarf. [NOIRLab/ only been looked at with small sam- NSF/AURA/J. da Silva/Spaceengine/M. Zamani, KPNO/P. Marenfeld, ESA/Hubble/ ples from Doppler surveys, which M. Kornmesser] typically have found giant planets further away from these red dwarf Telescope; and the Red Buttes Ob- water (meaning it would float if stars. Until now we have not had a servatory (RBO) in Wyoming. placed in a giant bathtub filled with large enough sample of planets to TESS surveyed the crossing of this water), or in fact, similar in density to find close-in gas planets in a robust planet TOI-3757 b in front of its star, a marshmallow. manner.” which allowed astronomers to calcu- “Potential future observations of the There are still unexplained mysteries late the planet’s diameter to be atmosphere of this planet using surrounding TOI-3757 b, the big one about 150,000 kilometers (100,000 NASA’s new James Webb Space Tel- being how a gas-giant planet can miles) or about just slightly larger escope could help shed light on its form around a red dwarf star, and than that of Jupiter. The planet fin- puffy nature,” says Jessica Libby- especially such a low-density planet. ishes one complete orbit around its Roberts, a postdoctoral researcher at Kanodia’s team, however, thinks host star in just 3.5 days, 25 times Pennsylvania State University and the they might have a solution to that less than the closest planet in our second author on this paper. mystery. Solar System — Mercury — which “Finding more such systems with They propose that the extra-low takes about 88 days to do so. giant planets — which were once density of TOI-3757 b could be the The astronomers then used NEID and theorized to be extremely rare result of two factors. The first relates HPF to measure the star’s apparent around red dwarfs — is part of our to the rocky core of the planet; gas motion along the line of sight, also goal to understand how planets giants are thought to begin as mas- known as its radial velocity. These form,” says Kanodia. The discovery sive rocky cores about ten times the measurements provided the planet’s highlights the importance of NEID in mass of Earth, at which point they mass, which was calculated to be its ability to confirm some of the can- rapidly pull in large amounts of about one quarter that of Jupiter, or didate exoplanets currently being neighboring gas to form the gas gi- about 85 times the mass of the Earth. discovered by NASA’s TESS mission, ants we see today. TOI-3757b’s star Knowing the size and the mass al- providing important targets for the has a lower abundance of heavy lowed Kanodia’s team to calculate new James Webb Space Telescope elements compared to other M- TOI-3757 b’s average density as being (JWST) to follow-up on and begin dwarfs with gas giants, and this may 0.27 grams per cubic centimeter characterizing their atmospheres. have resulted in the rocky core form- (about 17 grams per cubic feet), This will in turn inform astronomers ing more slowly, delaying the onset which would make it less than half what the planets are made of and of gas accretion and therefore af- the density of Saturn (the lowest- how they formed and, for potentially fecting the planet’s overall density. density planet in the Solar System), habitable rocky worlds, whether they The second factor may be the about one quarter the density of might be able to support life. planet’s orbit, which is tentatively thought to be slightly elliptical. There are times it gets closer to its star than at other times, resulting in substan- tial excess heating that can cause the planet’s atmosphere to bloat. The planet was initially spotted by NASA’s Transiting Exoplanet Survey Satellite (TESS). Kanodia’s team then made follow-up observations using ground-based instruments, includ- ing NEID and NESSI (NN-EXPLORE Exoplanet Stellar Speckle Imager), both housed at the WIYN 3.5-meter Telescope; the Habitable-zone Planet Finder (HPF) on the Hobby-Eberly JANUARY-FEBRUARY 2023
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