ST/ Scientists discover the highest-energy light coming from the sun

Paradigm

Published in

Paradigm

29 min readAug 17, 2023

Space biweekly vol.82, 3rd August — 17th August

TL;DR

New research details the discovery of the highest-energy light ever observed from the sun. The international team behind the discovery also found that this type of light, known as gamma rays, is surprisingly bright. That is, there’s more of it than scientists had previously anticipated.
The largest storm in the solar system, a 10,000-mile-wide anticyclone called the Great Red Spot, has decorated Jupiter’s surface for hundreds of years.
New observations of mud cracks made by the Curiosity Rover show that high-frequency, wet-dry cycling occurred in early Martian surface environments, indicating that the red planet may have once seen seasonal weather patterns or even flash floods.
International team reports on a radio pulsar phase of a Galactic magnetar that emitted a fast radio burst in 2020; observations suggest unique origins for ‘bursts’ and ‘pulses,’ which adds to FRB formation theory.
Last year, JWST made spectral observations of Ganymede and infrared observations of Io. Absorption lines of hydrogen peroxide at Ganymede’s poles indicate radiolysis of water ice by charged particles funneled by the moon’s magnetic field. Io had two major eruptions, one associated with a forbidden emission line of sulfur monoxide. The latter supports the theory that SO is produced at volcanic vents in a thin atmosphere that allows forbidden emission before collisions destroy the excited state.
An international team of scientists has discovered an unusual Jupiter-sized planet orbiting a low-mass star called TOI-4860, located in the Corvus constellation.
Researchers offer insight into the source of cosmic magnetic fields. The research team used models to show that magnetic fields may spontaneously arise in turbulent plasma. Their simulations showed that, in addition to generating new magnetic fields, the turbulence of those plasmas can also amplify magnetic fields once they’ve been generated, which helps explain how magnetic fields that originate on small scales can sometimes eventually reach to stretch across vast distances.
Scientists gain vital insights into Mars’ history and potential for supporting life.
Researchers have made major strides in confirming the source of dust in early galaxies. Observations of two Type II supernovae, Supernova 2004et (SN 2004et) and Supernova 2017eaw (SN 2017eaw), have revealed large amounts of dust within the ejecta of each of these objects. The mass found by researchers supports the theory that supernovae played a key role in supplying dust to the early universe.
Scientists have found a source for the mysterious alignment of stars near the Galactic Center.
And more!

Space industry in numbers

The global smart space market size is projected to grow from USD 9.4 billion in 2020 to USD 15.3 billion by 2025, at a Compound Annual Growth Rate (CAGR) of 10.2% during the forecast period. The increasing venture capital funding and growing investments in smart space technology to drive market growth.

Analysts at Morgan Stanley and Goldman Sachs have predicted that economic activity in space will become a multi-trillion-dollar market in the coming decades. Morgan Stanley’s Space Team estimates that the roughly USD 350 billion global space industry could surge to over USD 1 trillion by 2040.

Source: Satellite Industry Association, Morgan Stanley Research, Thomson Reuters. *2040 estimates

Space industry news

Latest research

Discovery of Gamma Rays from the Quiescent Sun with HAWC

by A. Albert, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, et al in Physical Review Letters

Sometimes, the best place to hide a secret is in broad daylight. Just ask the sun.

“The sun is more surprising than we knew,” said Mehr Un Nisa, a postdoctoral research associate at Michigan State University. “We thought we had this star figured out, but that’s not the case.” Nisa, who will soon be joining MSU’s faculty, is the corresponding author of a new paper that details the discovery of the highest-energy light ever observed from the sun. The international team behind the discovery also found that this type of light, known as gamma rays, is surprisingly bright. That is, there’s more of it than scientists had previously anticipated.

Although the high-energy light doesn’t reach the Earth’s surface, these gamma rays create telltale signatures that were detected by Nisa and her colleagues working with the High-Altitude Water Cherenkov Observatory, or HAWC.

“We now have observational techniques that weren’t possible a few years ago,” said Nisa, who works in the Department of Physics and Astronomy in the College of Natural Science. “In this particular energy regime, other ground-based telescopes couldn’t look at the sun because they only work at night,” she said. “Ours operates 24/7.”

In addition to working differently from conventional telescopes, HAWC looks a lot different from the typical telescope. Rather than a tube outfitted with glass lenses, HAWC uses a network of 300 large water tanks, each filled with about 200 metric tons of water. The network is nestled between two dormant volcano peaks in Mexico, more than 13,000 feet above sea level.

From this vantage point, it can observe the aftermath of gamma rays striking air in the atmosphere. Such collisions create what are called air showers, which are a bit like particle explosions that are imperceptible to the naked eye. The energy of the original gamma ray is liberated and redistributed amongst new fragments consisting of lower energy particles and light. It’s these particles — and the new particles they create on their way down — that HAWC can “see.” When the shower particles interact with water in HAWC’s tanks, they create what’s known as Cherenkov radiation that can be detected with the observatory’s instruments. Nisa and her colleagues began collecting data in 2015. In 2021, the team had accrued enough data to start examining the sun’s gamma rays with sufficient scrutiny.

“After looking at six years’ worth of data, out popped this excess of gamma rays,” Nisa said. “When we first saw it, we were like, ‘We definitely messed this up. The sun cannot be this bright at these energies.’”

Spectrum of the solar disk. The 6.1-year spectrum by HAWC is shown by the red solid line.

The sun gives off a lot of light spanning a range of energies, but some energies are more abundant than others. For example, through its nuclear reactions, the sun provides a ton of visible light — that is, the light we see. This form of light carries an energy of about 1 electron volt, which is a handy unit of measure in physics.

The gamma rays that Nisa and her colleagues observed had about 1 trillion electron volts, or 1 tera electron volt, abbreviated 1 TeV. Not only was this energy level surprising, but so was the fact that they were seeing so much of it. In the 1990s, scientists predicted that the sun could produce gamma rays when high-energy cosmic rays — particles accelerated by a cosmic powerhouse like a black hole or supernova — smash into protons in the sun. But, based on what was known about cosmic rays and the sun, the researchers also hypothesized it would be rare to see these gamma rays reach Earth. At the time, though, there wasn’t an instrument capable of detecting such high-energy gamma rays and there wouldn’t be for a while. The first observation of gamma rays with energies of more than a billion electron volts came from NASA’s Fermi Gamma-ray Space Telescope in 2011.

Over the next several years, the Fermi mission showed that not only could these rays be very energetic, but also that there were about seven times more of them than scientists had originally expected. And it looked like there were gamma rays left to discover at even higher energies. When a telescope launches into space, there’s a limit to how big and powerful its detectors can be. The Fermi telescope’s measurements of the sun’s gamma rays maxed out around 200 billion electron volts. Theorists led by John Beacom and Annika Peter, both professors at Ohio State University, encouraged the HAWC Collaboration to take a look.

“They nudged us and said, ‘We’re not seeing a cutoff. You might be able to see something,” Nisa said.

The HAWC Collaboration includes more than 30 institutions across North America, Europe and Asia, and a sizable portion of that is represented in the nearly 100 authors on the new paper. Now, for the first time, the team has shown that the energies of the sun’s rays extend into the TeV range, up to nearly 10 TeV, which does appear to be the maximum, Nisa said. Currently, the discovery creates more questions than answers. Solar scientists will now scratch their heads over how exactly these gamma rays achieve such high energies and what role the sun’s magnetic fields play in this phenomenon, Nisa said.

When it comes to the cosmos, though, that’s part of the excitement. It tells us that there was something wrong, missing or perhaps both when it comes to how we understand our nearest and dearest star.

“This shows that HAWC is adding to our knowledge of our galaxy at the highest energies, and it’s opening up questions about our very own sun,” Nisa said. “It’s making us see things in a different light. Literally.”

Long-lasting, deep effect of Saturn’s giant storms

by Cheng Li, Imke de Pater, Chris Moeckel, R. J. Sault, Bryan Butler, David deBoer, Zhimeng Zhang in Science Advances

The largest storm in the solar system, a 10,000-mile-wide anticyclone called the Great Red Spot, has decorated Jupiter’s surface for hundreds of years.

A new study now shows that Saturn — though much blander and less colorful than Jupiter — also has long-lasting megastorms with impacts deep in the atmosphere that persist for centuries. The study was conducted by astronomers from the University of California, Berkeley, and the University of Michigan, Ann Arbor, who looked at radio emissions from the planet, which come from below the surface, and found long-term disruptions in the distribution of ammonia gas.

Megastorms occur approximately every 20 to 30 years on Saturn and are similar to hurricanes on Earth, although significantly larger. But unlike Earth’s hurricanes, no one knows what causes megastorms in Saturn’s atmosphere, which is composed mainly of hydrogen and helium with traces of methane, water and ammonia.

“Understanding the mechanisms of the largest storms in the solar system puts the theory of hurricanes into a broader cosmic context, challenging our current knowledge and pushing the boundaries of terrestrial meteorology,” said lead author Cheng Li, a former 51 Peg b Fellow at UC Berkeley who is now an assistant professor at the University of Michigan.

Imke de Pater, a UC Berkeley professor emerita of astronomy and of earth and planetary sciences, has been studying gas giants for over four decades to better understand their composition and what makes them unique, employing the Karl G. Jansky Very Large Array in New Mexico to probe the radio emissions from deep inside the planet.

“At radio wavelengths, we probe below the visible cloud layers on giant planets. Since chemical reactions and dynamics will alter the composition of a planet’s atmosphere, observations below these cloud layers are required to constrain the planet’s true atmospheric composition, a key parameter for planet formation models,” she said. “Radio observations help characterize dynamical, physical and chemical processes including heat transport, cloud formation and convection in the atmospheres of giant planets on both global and local scales.”

As reported in the new study, de Pater, Li and UC Berkeley graduate student Chris Moeckel found something surprising in the radio emissions from the planet: anomalies in the concentration of ammonia gas in the atmosphere, which they connected to the past occurrences of megastorms in the planet’s northern hemisphere.

According to the team, the concentration of ammonia is lower at midaltitudes, just below the uppermost ammonia-ice cloud layer, but has become enriched at lower altitudes, 100 to 200 kilometers deeper in the atmosphere. They believe that the ammonia is being transported from the upper to the lower atmosphere via the processes of precipitation and reevaporation. What’s more, that effect can last for hundreds of years.

Sustained wet–dry cycling on early Mars

by W. Rapin, G. Dromart, B. C. Clark, J. Schieber, E. S. Kite, L. C. Kah, L. M. Thompson, O. Gasnault, J. Lasue, P.-Y. Meslin, P. J. Gasda, N. L. Lanza in Nature

New observations of mud cracks made by the Curiosity rover show that high-frequency, wet-dry cycling occurred in early Martian surface environments, indicating that the red planet may have once seen seasonal weather patterns or even flash floods.

“These exciting observations of mature mud cracks are allowing us to fill in some of the missing history of water on Mars. How did Mars go from a warm, wet planet to the cold, dry place we know today? These mud cracks show us that transitional time, when liquid water was less abundant but still active on the Martian surface,” said Nina Lanza, principal investigator of the ChemCam instrument onboard the Curiosity rover. “These features also point to the existence of wet-dry environments that on Earth are extremely conducive to the development of organic molecules and potentially life. Taken as a whole, these results a giving us a clearer picture of Mars as a habitable world.”

The presence of long-term wet environments, such as evidence of ancient lakes on Mars, is well-documented, but far less is known about short-term climate fluctuations. After years of exploring terrain largely composed of silicates, the rover entered a new area filled with sulfates, marking a major environment transition. In this new environment, the research team found a change in mud crack patterns, signifying a change in the way the surface would have dried. This indicates that water was still present on the surface of Mars episodically, meaning water could have been present for a time, evaporated, and repeated until polygons, or mud cracks, formed.

Larger color image of bedrock with polygonal ridges for context.

“A major focus of the Curiosity mission, and one of the main reasons for selecting Gale Crater, is to understand the transition of a ‘warm and wet’ ancient Mars to a ‘cold and dry’ Mars we see today,” said Patrick Gasda of the Laboratory’s Space Remote Sensing and Data Science group and coauthor of the paper. “The rover’s drive from clay lakebed sediments to drier non-lakebed and sulfate-rich sediments is part of this transition.”

On Earth, initial mud cracks in mud form a T-shaped pattern, but subsequent wetting and drying cycles cause the cracks to form more of a Y-shaped pattern, which is what Curiosity observed. Additionally, the rover found evidence that the mud cracks were only a few centimeters deep, which could mean that wet-dry cycles were seasonal, or may have even occurred more quickly, such as in a flash flood.

These findings could mean that Mars once had an Earth-like wet climate, with seasonal or short-term flooding, and that Mars may have been able to support life at some point.

“What’s important about this phenomenon is that it’s the perfect place for the formation of polymeric molecules required for life, including proteins and RNA, if the right organic molecules were present at this location,” Gasda said “Wet periods bring molecules together while dry periods drive reactions to form polymers. When these processes occur repeatedly at the same location, the chance increases that more complex molecules formed there.”

A radio pulsar phase from SGR J1935+2154 provides clues to the magnetar FRB mechanism

by Weiwei Zhu, Heng Xu, Dejiang Zhou, et al in Science Advance

More than 15 years after the discovery of fast radio bursts (FRBs) — millisecond-long, deep-space cosmic explosions of electromagnetic radiation — astronomers worldwide have been combing the universe to uncover clues about how and why they form.

Nearly all FRBs identified have originated in deep space outside our Milky Way galaxy. That is until April 2020, when the first Galactic FRB, named FRB 20200428, was detected. This FRB was produced by a magnetar (SGR J1935+2154), a dense, city-sized neutron star with an incredibly powerful magnetic field.

This groundbreaking discovery led some to believe that FRBs identified at cosmological distances outside our galaxy may also be produced by magnetars. However, the smoking gun for such a scenario, a rotation period due to the spin of the magnetar, has so far escaped detection. New research into SGR J1935+2154 sheds light on this curious discrepancy. An international team of scientists, including UNLV astrophysicist Bing Zhang, report on continued monitoring of SGR J1935+2154 following the April 2020 FRB, and the discovery of another cosmological phenomenon known as a radio pulsar phase five months later.

To aid them in their quest for answers, astronomers rely in part on powerful radio telescopes like the massive Five-hundred-meter Aperture Spherical radio Telescope (FAST) in China to track FRBs and other deep-space activity. Using FAST, astronomers observed that FRB 20200428 and the later pulsar phase originated from different regions within the scope of the magnetar, which hints towards different origins.

“FAST detected 795 pulses in 16.5 hours over 13 days from the source,” said Weiwei Zhu, lead author of the paper from National Astronomical Observatory of China (NAOC). “These pulses show different observational properties from the bursts observed from the source.”

This dichotomy in emission modes from the region of a magnetosphere helps astronomers understand how — and where — FRBs and related phenomena occur within our galaxy and perhaps also those at further cosmological distances.

The radio and x-ray campaign and the bursts’ rotational phases.

Radio pulses are cosmic electromagnetic explosions, similar to FRBs, but typically emit a brightness roughly 10 orders of magnitude less than an FRB. Pulses are typically observed not in magnetars but in other rotating neutron stars known as pulsars. According to Zhang, a corresponding author on the paper and director of the Nevada Center for Astrophysics, most magnetars do not emit radio pulses most of the time, probably due to their extremely strong magnetic fields. But, as was the case with SGR J1935+2154, some of them become temporary radio pulsars after some bursting activities. Another trait that makes bursts and pulses different are their emission “phases,” i.e. the time window where radio emission is emitted in each period of emission.

“Like pulses in radio pulsars, the magnetar pulses are emitted within a narrow phase window within the period,” said Zhang. “This is the well-known `lighthouse’ effect, namely, the emission beam sweeps the line of sight once a period and only during a short interval in time in each period. One can then observe the pulsed radio emission.”

Zhang said the April 2020 FRB, and several later, less energetic bursts were emitted in random phases not within the pulse window identified in the pulsar phase.

“This strongly suggests that pulses and bursts originate from different locations within the magnetar magnetosphere, suggesting possibly different emission mechanisms between pulses and bursts,” he said.

Such a detailed observation of a Galactic FRB source sheds light on the mysterious FRBs prevailing at cosmological distances. Many sources of cosmological FRBs — those occurring outside our galaxy — have been observed to repeat. In some instances, FAST has detected thousands of repeated bursts from a few sources. Deep searches for seconds-level periodicity have been carried out using these bursts in the past and so far no period was discovered. According to Zhang, this casts doubt on the popular idea that repeating FRBs are powered by magnetars in the past.

“Our discovery that bursts tend to be generated in random phases provides a natural interpretation to the non-detection of periodicity from repeating FRBs,” he said. “For unknown reasons, bursts tend to be emitted in all directions from a magnetar, making it impossible to identify periods from FRB sources.”

Hydrogen peroxide at the poles of Ganymede

by Samantha K. Trumbo, Michael E. Brown, et al in Science Advances

With its sensitive infrared cameras and high-resolution spectrometer, the James Webb Space Telescope (JWST) is revealing new secrets of Jupiter’s Galilean satellites, in particular Ganymede, the largest moon, and Io, the most volcanically active.

In two separate publications, astronomers who are part of JWST’s Early Release Science program report the first detection of hydrogen peroxide on Ganymede and sulfurous fumes on Io, both the result of Jupiter’s domineering influence.

“This shows that we can do incredible science with the James Webb Space Telescope on solar system objects, even if the object is really very bright, like Jupiter, but also when you look at very faint things next to Jupiter,” said Imke de Pater, professor emerita of astronomy and earth and planetary science at the University of California, Berkeley. De Pater and Thierry Fouchet from the Paris Observatory are co-principal investigators for the Early Release Science solar system observation team, one of 13 teams given early access to the telescope.

Samantha Trumbo, a 51 Pegasi b postdoctoral fellow at Cornell University, led the study of Ganymede. Using measurements captured by the near-infrared spectrometer (NIRSpec) on JWST, the team detected the absorption of light by hydrogen peroxide — H2O2 — around the north and south poles of the moon, a result of charged particles around Jupiter and Ganymede impacting the ice that blankets the moon.

“JWST revealing the presence of hydrogen peroxide at Ganymede’s poles shows for the first time that charged particles funneled along Ganymede’s magnetic field are preferentially altering the surface chemistry of its polar caps,” Trumbo said.

The astronomers argue that the peroxide is produced by charged particles hitting the frozen water ice around the poles and breaking the water molecules into fragments — a process called radiolysis — which then recombine to form H2O2. They suspected that radiolysis would occur primarily around the poles on Ganymede because, unlike all other moons in our solar system, it has a magnetic field that directs charged particles toward the poles.

“Just like how Earth’s magnetic field directs charged particles from the sun to the highest latitudes, causing the aurora, Ganymede’s magnetic field does the same thing to charged particles from Jupiter’s magnetosphere,” she added. “Not only do these particles result in aurorae at Ganymede, as well, but they also impact the icy surface.”

Trumbo and Michael Brown, professor of planetary astronomy at Caltech, where Trumbo recently received her Ph.D., had earlier studied hydrogen peroxide on Europa, another of Jupiter’s four Galilean satellites. On Europa, however, the peroxide was detectable over much of the surface, perhaps, in part, because it has no magnetic field to protect the surface from the fast-moving particles zipping around Jupiter.

Average JWST spectra of Ganymede for different latitude bins across the leading and trailing hemispheres.

“This is likely a really important and widespread process,” Trumbo said. “These observations of Ganymede provide a key window to understand how such water radiolysis might drive chemistry on icy bodies throughout the outer solar system, including on neighboring Europa and Callisto (the fourth Galilean moon).”
“It helps to actually understand how this so-called radiolysis works and that, indeed, it works as people expected, based on lab experiments on Earth,” de Pater said.

De Pater and her colleagues report new Webb observations of Io that show several ongoing eruptions, including a brightening at a volcanic complex called Loki Patera and an exceptionally bright eruption at Kanehekili Fluctus. Because Io is the only volcanically active moon in the solar system — Jupiter’s gravitational push and pull heats it up — studies like this give planetary scientists a different perspective than can be obtained by studying volcanos on Earth.

For the first time, the researchers were able to link a volcanic eruption — at Kanehekili Fluctus — to a specific emission line, a so-called “forbidden” line, of the gas sulfur monoxide (SO). Sulfur dioxide (SO2) is the main component of Io’s atmosphere, coming from sublimation of SO2 ice, as well as ongoing volcanic eruptions, similar to the production of SO2 by volcanos on Earth. The volcanos also produce SO, which is much harder to detect than SO2. In particular, the forbidden SO emission line is very weak because SO is in such low concentrations and produced for only a short time after being excited. Moreover, the observations can only be made when Io is in Jupiter’s shadow, when it is easier to see the glowing SO gases. When Io is in Jupiter’s shadow, the SO2 gas in Io’s atmosphere freezes out onto its surface, leaving only SO and newly emitted volcanic SO2 gas in the atmosphere.

An M dwarf accompanied by a close-in giant orbiter with SPECULOOS

by Amaury H M J Triaud, Georgina Dransfield, et al in Monthly Notices of the Royal Astronomical Society: Letters

An international team of scientists have discovered an unusual Jupiter-sized planet orbiting a low-mass star called TOI-4860, located in the Corvus constellation.

The newly discovered gas giant, named TOI-4860 b, is an unusual planet for two reasons: stars of such low mass are not expected to host planets like Jupiter, and the planet appears to be particularly enriched by heavy elements.

The planet was initially identified using NASA’s Transiting Exoplanet Survey Satellite as a drop of brightness while transiting in front of its host star, but that data alone was insufficient to confirm that it was a planet. The team used the SPECULOOS South Observatory, located in the Atacama Desert in Chile, to measure the planetary signal in several wavelengths and validated the planetary nature. The astronomers also observed the planet just before and after it disappeared behind its host star, noticing that there was no change in light, meaning the planet was not emitting any. Finally, the team collaborated with a Japanese group using the Subaru Telescope in Hawai’i. Together they measured the mass of the planet to fully confirm it.

Following this star and confirming its planet was the initiative of a group of PhD students within the SPECULOOS project.

George Dransfield, one of those PhD students, who recently submitted her thesis at the University of Birmingham, explains: “Under the canonical planet formation model, the less mass a star has, the less massive is the disc of material around that star.
“Since planets are created from that disc, high-mass planets like Jupiter, were widely expected not to form. However, we were curious about this and wanted to check planetary candidates to see if it was possible. TOI-4860 is our first confirmation and also the lowest mass star hosting such a high mass planet.”

The figure shows all of the photometric data.

Amaury Triaud, Professor of Exoplanetology at the University of Birmingham, who led the study said: “I am ever thankful to the bright PhD students of our team for proposing to observe systems like TOI-4860. Their work has really paid off since planets like TOI-4860 are vital to deepening our understanding of planet formation.
“A hint of what might have happened is hidden in the planetary properties, which appear particularly enriched in heavy elements. We have detected something similar in the host star too, so it is likely that an abundance of heavy elements catalysed the planet formation process.”

The new gas giant takes about 1.52 days to complete a full orbit around its host star, but because its host is a cold low mass star, the planet itself can be referred to as a ‘Warm Jupiter’. This is a subclass of the planet that holds particular interest for astronomers looking to build on their initial observations and learn more about how these kinds of planets are formed.

Generation of Near-Equipartition Magnetic Fields in Turbulent Collisionless Plasmas

by Lorenzo Sironi, Luca Comisso, Ryan Golant in Physical Review Letters

It isn’t just your refrigerator that has magnets on it. The earth, the stars, galaxies, and the space between galaxies are all magnetized, too. The more places scientists have looked for magnetic fields across the universe, the more they’ve found them. But the question of why that is the case and where those magnetic fields originate from has remained a mystery and a subject of ongoing scientific inquiry.

A new paper by Columbia researchers offers insight into the source of these fields. The team used models to show that magnetic fields may spontaneously arise in turbulent plasma. Plasma is a kind of matter often found in ultra-hot environments like that near the surface of the sun, but plasma is also scattered across the universe in low-density environments, like the expansive space between galaxies; the team’s research focused on those low-density environments. Their simulations showed that, in addition to generating new magnetic fields, the turbulence of those plasmas can also amplify magnetic fields once they’ve been generated, which helps explain how magnetic fields that originate on small scales can sometimes eventually reach to stretch across vast distances.

The paper was written by astronomy professor Lorenzo Sironi, astronomy research scientist Luca Comisso, and astronomy doctoral candidate Ryan Golant.

Representative 2D slices from the 3D reference simulation.

“This new research allows us to imagine the kinds of spaces where magnetic fields are born: even in the most pristine, vast, and remote spaces of our universe, roiling plasma particles in turbulent motion can spontaneously give birth to new magnetic fields,” Sironi said. “The search for the ‘seed’ that can sow a new magnetic field has been long, and we’re excited to bring new evidence of that original source, as well as data on how a magnetic field, once born, can grow.”

Diverse organic-mineral associations in Jezero crater, Mars

by Sunanda Sharma, Ryan D. Roppel, Ashley E. Murphy, et al in Nature

A new study featuring data from the NASA Mars Perseverance rover has presented compelling evidence for organic material on the Martian surface, shedding light on the potential habitability of the Red Planet. The research, is led by a team of scientists that includes UF astrobiologist Amy Williams.

Scientists have long been fueled by the possibility of finding organic carbon on Mars, and while previous missions provided valuable insights, the latest research introduces a new line of evidence that adds to our understanding of Mars. The findings indicate the presence of a more intricate organic geochemical cycle on Mars than previously understood, suggesting the existence of several distinct reservoirs of potential organic compounds.

Notably, the study detected signals consistent with molecules linked to aqueous processes, indicating that water may have played a key role in the diverse range of organic matter on Mars. The key building blocks necessary for life may have persisted on Mars for a far more extended period than previously thought.

Amy Williams, an expert in organic geochemistry, has been at the forefront of the search for life’s building blocks on Mars. As a participating scientist on the Perseverance mission, Williams’ work centers on the quest for organic matter on the Red Planet. She aims to detect habitable environments, search for potential life materials, and uncover evidence of past life on Mars. Eventually, the on-site samples collected by Perseverance will be sent back to Earth by future missions, but it will be a complex and ambitious process spanning many years.

Overview of targets analysed by SHERLOC during the crater floor campaign.

“The potential detection of several organic carbon species on Mars has implications for understanding the carbon cycle on Mars, and the potential of the planet to host life throughout its history,” said Williams, an assistant professor in UF’s Department of Geological Sciences.

Organic matter can be formed from various processes, not just those related to life. Geological processes and chemical reactions can also form organic molecules, and these processes are favored for the origin of these possible Martian organics. Williams and the team of scientists will work to further examine the potential sources of these molecules.

Until now, organic carbon had only been detected by the Mars Phoenix lander and the Mars Curiosity rover by using advanced techniques like evolved gas analysis and gas chromatography-mass spectrometry. The new study introduces a different technique that also potentially identifies simple organic compounds on Mars. The chosen landing site for the rover within Jezero crater offers a high potential for past habitability: As an ancient lake basin, it contains an array of minerals, including carbonates, clays, and sulfates. These minerals have the potential to preserve organic materials and possible signs of ancient life.

“We didn’t initially expect to detect these potential organics signatures in the Jezero crater floor,” Williams said, “but their diversity and distribution in different units of the crater floor now suggest potentially different fates of carbon across these environments.”

The scientists used a first-of-its-kind instrument called the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) to map the distribution of organic molecules and minerals on rock surfaces. SHERLOC employs deep ultraviolet Raman and fluorescence spectroscopy to simultaneously measure weak Raman scattering and strong fluorescence emissions, providing crucial insights into the organic composition of Mars. The findings mark a significant step forward in our exploration of the Red Planet, laying the groundwork for future investigations into the possibility of life beyond Earth.

JWST observations of dust reservoirs in type IIP supernovae 2004et and 2017eaw

by Melissa Shahbandeh, Arkaprabha Sarangi, et al Monthly Notices of the Royal Astronomical Society

Researchers using NASA’s James Webb Space Telescope have made major strides in confirming the source of dust in early galaxies. Observations of two Type II supernovae, Supernova 2004et (SN 2004et) and Supernova 2017eaw (SN 2017eaw), have revealed large amounts of dust within the ejecta of each of these objects. The mass found by researchers supports the theory that supernovae played a key role in supplying dust to the early universe.

Dust is a building block for many things in our universe — planets in particular. As dust from dying stars spreads through space, it carries essential elements to help give birth to the next generation of stars and their planets. Where that dust comes from has puzzled astronomers for decades. One significant source of cosmic dust could be supernovae — after the dying star explodes, its leftover gas expands and cools to create dust.

“Direct evidence of this phenomenon has been slim up to this point, with our capabilities only allowing us to study the dust population in one relatively nearby supernova to date — Supernova 1987A, 170,000 light-years away from Earth,” said lead author Melissa Shahbandeh of Johns Hopkins University and the Space Telescope Science Institute in Baltimore, Maryland. “When the gas cools enough to form dust, that dust is only detectable at mid-infrared wavelengths provided you have enough sensitivity.”

For supernovae more distant than SN 1987A like SN 2004et and SN 2017eaw, both in NGC 6946 about 22 million light-years away, that combination of wavelength coverage and exquisite sensitivity can only be obtained with Webb’s MIRI (Mid-Infrared Instrument).

The Webb observations are the first breakthrough in the study of dust production from supernovae since the detection of newly formed dust in SN 1987A with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope nearly a decade ago. Another particularly intriguing result of their study isn’t just the detection of dust, but the amount of dust detected at this early stage in the supernova’s life. In SN 2004et, the researchers found more than 5,000 Earth masses of dust.

“When you look at the calculation of how much dust we’re seeing in SN 2004et especially, it rivals the measurements in SN 1987A, and it’s only a fraction of the age,” added program lead Ori Fox of the Space Telescope Science Institute. “It’s the highest dust mass detected in supernovae since SN 1987A.”

Observations have shown astronomers that young, distant galaxies are full of dust, but these galaxies are not old enough for intermediate-mass stars, like the Sun, to have supplied the dust as they age. More massive, short-lived stars could have died soon enough and in large enough numbers to create that much dust.

While astronomers have confirmed that supernovae produce dust, the question has lingered about how much of that dust can survive the internal shocks reverberating in the aftermath of the explosion. Seeing this amount of dust at this stage in the lifetimes of SN 2004et and SN 2017eaw suggests that dust can survive the shockwave — evidence that supernovae really are important dust factories after all.

Researchers also note that the current estimations of the mass may be the tip of the iceberg. While Webb has allowed researchers to measure dust cooler than ever before, there may be undetected, colder dust radiating even farther into the electromagnetic spectrum that remains obscured by the outermost layers of dust. The researchers emphasized that the new findings are also just a hint at newfound research capabilities into supernovae and their dust production using Webb, and what that can tell us about the stars from which they came.

“There’s a growing excitement to understand what this dust also implies about the core of the star that exploded,” Fox said. “After looking at these particular findings, I think our fellow researchers are going to be thinking of innovative ways to work with these dusty supernovae in the future.”

When the Stars Align: A 5σ Concordance of Planetary Nebulae Major Axes in the Center of Our Galaxy

by Shuyu Tan, Quentin A. Parker, Albert A. Zijlstra, Andreas Ritter, Bryan Rees in The Astrophysical Journal Letters

A collaboration of scientists from The University of Manchester and the University of Hong Kong have found a source for the mysterious alignment of stars near the Galactic Centre.

The alignment of planetary nebulae was discovered ten years ago by a Manchester PhD student, Bryan Rees, but has remained unexplained. New data obtained with the European Southern Observatory Very Large Telescope in Chile and the Hubble Space Telescope, has confirmed the alignment but also found a particular group of stars that is responsible, namely close binary stars.

Planetary nebulae are clouds of gas that are expelled by stars at the end of their lives — the Sun will also form one about five billion years from now. The ejected clouds are ‘ghosts’ of their dying stars and they form beautiful structures such as an hourglass or butterfly shape.

The team studied a group of so-called planetary nebulae found in the Galactic Bulge near the centre of our Milky Way. Each of these nebulae are unrelated and come from different stars, which were born at different times, and spend their lives in completely different places. However, the study found that many of their shapes line up in the sky in the same way and are aligned almost parallel to the Galactic plane (our Milky Way). This is in the same direction as found by Bryan Rees a decade ago. The new research, led by Shuyu Tan, a student at the University of Hong Kong, found that the alignment is present only in planetary nebulae which have a close stellar companion. The companion star orbits the main star at the centre of the planetary nebulae in an orbit closer than Mercury is to our own Sun.

Measurement of the equatorial position angle (EPA). The orientation axis measured from the projected 2D image of a bulge PN was determined visually and the axis that best represents the long symmetry of each PN.

The planetary nebulae that do not show close companions do not show the alignment, which suggests that the alignment is potentially linked to the initial separation of the binary components at the time of the star’s birth.

Albert Zijlstra, co-author and Professor in Astrophysics at The University of Manchester, said: “This finding pushes us closer to understanding the cause for this mysterious alignment. “Planetary nebulae offer us a window into the heart of our galaxy and this insight deepens our understanding of the dynamics and evolution of the Milky Way’s bulge region.
“The formation of stars in the bulge of our galaxy is a complex process that involves various factors such as gravity, turbulence, and magnetic fields. Until now, we have had a lack of evidence for which of these mechanisms could be causing this process to happen and generating this alignment.
“The significance in this research lies in the fact that we now know that the alignment is observed in this very specific subset of planetary nebulae.”

The researchers investigated 136 confirmed planetary nebulae in the galaxy bulge — the thickest section of our Milky Way composed of stars, gas and dust — using the European Southern Observatory Very Large Telescope, which has a main mirror diameter of eight metres. They also re-examined and re-measured 40 of these from the original study using images from the high-resolution Hubble Space Telescope. Prof Quentin Parker, the corresponding author from the University of Hong Kong, suggests the nebulae may be shaped by the rapid orbital motion of the companion star, which may even end up orbiting inside the main star.

The alignment of the nebulae may mean that the close binary system preferentially forms with their orbits in the same plane. Although further studies are needed to fully understand the mechanisms behind the alignment, the findings provide important evidence for the presence of a constant and controlled process that has influenced star formation over billions of years and vast distances.