ST/ Astronomers spot 18 black holes gobbling up nearby stars

Paradigm

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Paradigm

41 min readFeb 8, 2024

Space biweekly vol.91, 19th January — 8th February

TL;DR

Scientists have identified 18 new tidal disruption events (TDEs) — extreme instances when a nearby star is tidally drawn into a black hole and ripped to shreds. The detections more than double the number of known TDEs in the nearby universe.
Although solar flares have been classified based on the amount of energy they emit at their peak, there has not been significant study into differentiating flares since slow-building flares were first discovered in the 1980s. Scientists have now shown that there is a significant amount of slower-type flares worthy of further investigation.
Astronomers have shown new atmospheric detail in a set of 15 exoplanets similar to Neptune. While none could support humanity, a better understanding of their behavior might help us to understand why we don’t have a small Neptune, while most solar systems seem to feature a planet of this class.
TOI-1136, a dwarf star located more than 270 light years from Earth, is host to six confirmed exoplanets and a seventh as yet unconfirmed candidate. The system has provided a rich source of information on planet formation and evolution in a young solar system. Researchers used a variety of tools to compile radial velocity and transit timing variation readings to derive highly precise measurements of the exoplants’ masses, orbital information and atmospheres.
A research team has for the first time discovered anomalous meter-sized rocks on the lunar surface that are covered in dust and presumably exhibit unique properties — such as magnetic anomalies. These findings help to understand the processes that form and change the lunar crust.
An international team of astronomers have found a new and unknown object in the Milky Way that is heavier than the heaviest neutron stars known and yet simultaneously lighter than the lightest black holes known.
The microquasar SS 433 stands out as one of the most intriguing objects within our Milky Way. A pair of oppositely directed beams of plasma (‘jets’) spirals away perpendicularly from the binary systems disk’s surface at just over a quarter of the speed of light. The H.E.S.S. observatory in Namibia has now succeeded in detecting very high energy gamma rays from the jets of SS 433, and identifying the exact location within the jets of one of the galaxy’s most effective particle accelerators.
A pancake stack of radioactivity-sensitive films carried through the sky by a balloon was able to take the world’s most accurate picture of a neutron star’s gamma ray beam. To achieve this, researchers combined the oldest method of capturing radioactive radiation with the newest data capturing techniques and a clever time-recording device.
Physicists discovered stars near the edge of the Milky Way travel more slowly than those closer to its center — a surprise suggesting our galaxy’s gravitational core may have less dark matter than previously thought.
Scientists say that astronomers’ best chance of finding liquid water, and even life on other planets, is to look for the absence, rather than the presence, of a chemical feature in their atmospheres.
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

A New Population of Mid-infrared-selected Tidal Disruption Events: Implications for Tidal Disruption Event Rates and Host Galaxy Properties

by Megan Masterson, Kishalay De, Christos Panagiotou, Erin Kara, Iair Arcavi, Anna-Christina Eilers, Danielle Frostig, Suvi Gezari, Iuliia Grotova, Zhu Liu, Adam Malyali, Aaron M. Meisner, Andrea Merloni, Megan Newsome, Arne Rau, Robert A. Simcoe, Sjoert van Velzen in The Astrophysical Journal

Star-shredding black holes are everywhere in the sky if you just know how to look for them. That’s one message from a new study by MIT scientists. The study’s authors are reporting the discovery of 18 new tidal disruption events (TDEs) — extreme instances when a nearby star is tidally drawn into a black hole and ripped to shreds. As the black hole feasts, it gives off an enormous burst of energy across the electromagnetic spectrum.

Astronomers have detected previous tidal disruption events by looking for characteristic bursts in the optical and X-ray bands. To date, these searches have revealed about a dozen star-shredding events in the nearby universe. The MIT team’s new TDEs more than double the catalog of known TDEs in the universe.

The researchers spotted these previously “hidden” events by looking in an unconventional band: infrared. In addition to giving off optical and X-ray bursts, TDEs can generate infrared radiation, particularly in “dusty” galaxies, where a central black hole is enshrouded with galactic debris. The dust in these galaxies normally absorbs and obscures optical and X-ray light, and any sign of TDEs in these bands. In the process, the dust also heats up, producing infrared radiation that is detectable. The team found that infrared emissions, therefore, can serve as a sign of tidal disruption events.

By looking in the infrared band, the MIT team picked out many more TDEs, in galaxies where such events were previously hidden. The 18 new events occurred in different types of galaxies, scattered across the sky.

“The majority of these sources don’t show up in optical bands,” says lead author Megan Masterson, a graduate student in MIT’s Kavli Institute for Astrophysics and Space Research. “If you want to understand TDEs as a whole and use them to probe supermassive black hole demographics, you need to look in the infrared band.”

Credit: Courtesy of the researchers, edited by MIT News

The team recently detected the closest TDE yet, by searching through infrared observations. The discovery opened a new, infrared-based route by which astronomers can search for actively feeding black holes. That first detection spurred the group to comb for more TDEs. For their new study, the researchers searched through archival observations taken by NEOWISE — the renewed version of NASA’s Wide-field Infrared Survey Explorer. This satellite telescope launched in 2009 and after a brief hiatus has continued to scan the entire sky for infrared “transients,” or brief bursts.

The team looked through the mission’s archived observations using an algorithm developed by co-author Kishalay De. This algorithm picks out patterns in infrared emissions that are likely signs of a transient burst of infrared radiation. The team then cross-referenced the flagged transients with a catalog of all known nearby galaxies within 200 megaparsecs, or 600 million light years. They found that infrared transients could be traced to about 1,000 galaxies.

They then zoomed in on the signal of each galaxy’s infrared burst to determine whether the signal arose from a source other than a TDE, such as an active galactic nucleus or a supernova. After ruling out these possibilities, the team then analyzed the remaining signals, looking for an infrared pattern that is characteristic of a TDE — namely, a sharp spike followed by a gradual dip, reflecting a process by which a black hole, in ripping apart a star, suddenly heats up the surrounding dust to about 1,000 kelvins before gradually cooling down.

This analysis revealed 18 “clean” signals of tidal disruption events. The researchers took a survey of the galaxies in which each TDE was found, and saw that they occurred in a range of systems, including dusty galaxies, across the entire sky.

“If you looked up in the sky and saw a bunch of galaxies, the TDEs would occur representatively in all of them,” Masteron says. “It’s not that they’re only occurring in one type of galaxy, as people thought based only on optical and X-ray searches.”
“It is now possible to peer through the dust and complete the census of nearby TDEs,” says Edo Berger, professor of astronomy at Harvard University, who was not involved with the study. “A particularly exciting aspect of this work is the potential of follow-up studies with large infrared surveys, and I’m excited to see what discoveries they will yield.”

Multiwavelength light curves for the 18 sources in our full sample, with gold sample sources marked with a star.

The team’s discoveries help to resolve some major questions in the study of tidal disruption events. For instance, prior to this work, astronomers had mostly seen TDEs in one type of galaxy — a “post-starburst” system that had previously been a star-forming factory, but has since settled. This galaxy type is rare, and astronomers were puzzled as to why TDEs seemed to be popping up only in these rarer systems. It so happens that these systems are also relatively devoid of dust, making a TDE’s optical or X-ray emissions naturally easier to detect.

Now, by looking in the infrared band, astronomers are able to see TDEs in many more galaxies. The team’s new results show that black holes can devour stars in a range of galaxies, not only post-starburst systems.

The findings also resolve a “missing energy” problem. Physicists have theoretically predicted that TDEs should radiate more energy than what has been actually observed. But the MIT team now say that dust may explain the discrepancy. They found that if a TDE occurs in a dusty galaxy, the dust itself could absorb not only optical and X-ray emissions but also extreme ultraviolet radiation, in an amount equivalent to the presumed “missing energy.”

The 18 new detections also are helping astronomers estimate the rate at which TDEs occur in a given galaxy. When they figure the new TDEs in with previous detections, they estimate a galaxy experiences a tidal disruption event once every 50,000 years. This rate comes closer to physicists’ theoretical predictions. With more infrared observations, the team hopes to resolve the rate of TDEs, and the properties of the black holes that power them.

“People were coming up with very exotic solutions to these puzzles, and now we’ve come to the point where we can resolve all of them,” Kara says. “This gives us confidence that we don’t need all this exotic physics to explain what we’re seeing. And we have a better handle on the mechanics behind how a star gets ripped apart and gobbled up by a black hole. We’re understanding these systems better.”

Solar Flare Catalogue from 3 Years of Chandrayaan-2 XSM Observations

by Aravind Bharathi Valluvan, Ashwin Goyal, Devansh Jain, Abhinna Sundar Samantaray, Abhilash Sarwade, Kasiviswanathan Sankarasubramanian in Solar Physics

Solar flares occur when magnetic energy builds up in the Sun’s atmosphere and is released as electromagnetic radiation. Lasting anywhere from a few minutes to a few hours, flares usually reach temperatures around 10 million degrees Kelvin. Because of their intense electromagnetic energy, solar flares can cause disruptions in radio communications, Earth-orbiting satellites and even result in blackouts.

Although flares have been classified based on the amount of energy they emit at their peak, there has not been significant study into differentiating flares based on the speed of energy build-up since slow-building flares were first discovered in the 1980s. In a new paper, a team, led by UC San Diego astrophysics graduate student Aravind Bharathi Valluvan, has shown that there is a significant amount of slower-type flares worthy of further investigation.

The width-to-decay ratio of a flare is the time it takes to reach maximum intensity to the time it takes to dissipate its energy. Most commonly, flares spend more time dissipating than rising. In a 5-minute flare, it may take 1 minute to rise and 4 minutes to dissipate for a ratio of 1:4. In slow-building flares, that ratio may be 1:1, with 2.5 minutes to rise and 2.5 minutes to dissipate.

*This image, taken on Aug. 5, 2023, shows a blend of extreme ultraviolet light that highlights the intensely hot material in flares and which is colorized in red and orange. (cr: NASA/GSFC/SDO)*

Valluvan was a student at the Indian Institute of Technology Bombay (IITB) when this work was conducted. Exploiting the increased capabilities of the Chandrayaan-2 solar orbiter, IITB researchers used the first three years of observed data to catalog nearly 1400 slow-rising flares — a dramatic increase over the roughly 100 that had been previously observed over the past four decades.

It was thought that solar flares were like the snap of a whip — quickly injecting energy before slowly dissipating. Now seeing slow-building flares in such high quantities may change that thinking.

“There is thrilling work to be done here,” stated Valluvan who now works in UC San Diego Professor of Astronomy and Astrophysics Steven Boggs’ group. “We’ve identified two different types of flares, but there may be more. And where do the processes differ? What makes them rise and fall at different rates? This is something we need to understand.”

Clouds and Clarity: Revisiting Atmospheric Feature Trends in Neptune-size Exoplanets

by Jonathan Brande, Ian J. M. Crossfield, Laura Kreidberg, Caroline V. Morley, Travis Barman, Björn Benneke, Jessie L. Christiansen, Diana Dragomir, Jonathan J. Fortney, Thomas P. Greene, Kevin K. Hardegree-Ullman, Andrew W. Howard, Heather A. Knutson, Joshua D. Lothringer, Thomas Mikal-Evans in The Astrophysical Journal Letters

The study of “exoplanets,” the sci-fi-sounding name for all planets in the cosmos beyond our own solar system, is a pretty new field. Mainly, exoplanet researchers like those in the ExoLab at the University of Kansas use data from space-borne telescopes such as the Hubble Space Telescope and Webb Space Telescope. Whenever news headlines offer findings of “Earth-like” planets or planets with the potential to support humanity, they’re talking about exoplanets within our own Milky Way.

Jonathan Brande, a doctoral candidate in the ExoLab at the University of Kansas, has just published findings showing new atmospheric detail in a set of 15 exoplanets similar to Neptune. While none could support humanity, a better understanding of their behavior might help us to understand why we don’t have a small Neptune, while most solar systems seem to feature a planet of this class.

“Over the past several years at KU, my focus has been studying the atmospheres of exoplanets through a technique known as transmission spectroscopy,” Brande said. “When a planet transits, meaning it moves between our line of sight and the star it orbits, light from the star passes through the planet’s atmosphere, getting absorbed by the various gases present. By capturing a spectrum of the star — passing the light through an instrument called a spectrograph, akin to passing it through a prism — we observe a rainbow, measuring the brightness of different constituent colors. Varied areas of brightness or dimness in the spectrum reveal the gases absorbing light in the planet’s atmosphere.”

With this methodology, several years ago Brande published a paper concerning the “warm Neptune” exoplanet TOI-674 b, where he presented observations indicating the presence of water vapor in its atmosphere. These observations were part of a broader program led by Brande’s adviser, Ian Crossfield, associate professor of physics & astronomy at KU, to observe atmospheres of Neptune-sized exoplanets.

This work’s sample overlaid with known transiting planets. Hexagons indicate planets in our sample also being observed by JWST through Cycle 2, while triangles are not yet scheduled or approved for JWST observations. Selected targets have been labeled.

“We want to comprehend the behaviors of these planets, given that those slightly larger than Earth and smaller than Neptune are the most common in the galaxy,” Brande said.

This recent ApJL paper summarizes observations from that program, incorporating data from additional observations to address why some planets appear cloudy while others are clear.

“The goal is to explore the physical explanations behind the distinct appearances of these planets,” Brande said.

Brande and his co-authors took special note of regions where exoplanets tend to form clouds or hazes high up in their atmosphere. When such atmospheric aerosols are present, the KU researcher said hazes can block the light filtering through the atmosphere.

“If a planet has a cloud right above the surface with hundreds of kilometers of clear air above it, starlight can easily pass through the clear air and be absorbed only by the specific gases in that part of the atmosphere,” Brande said. “However, if the cloud is positioned very high, clouds are generally opaque across the electromagnetic spectrum. While hazes have spectral features, for our work, where we focus on a relatively narrow range with Hubble, they also produce mostly flat spectra.”

According to Brande, when these aerosols are present high in the atmosphere, there’s no clear path for light to filter through.

“With Hubble, the single gas we’re most sensitive to is water vapor,” he said. “If we observe water vapor in a planet’s atmosphere, that’s a good indication that there are no clouds high enough to block its absorption. Conversely, if water vapor is not observed and only a flat spectrum is seen, despite knowing that the planet should have an extended atmosphere, it suggests the likely presence of clouds or hazes at higher altitudes.”

Brande led the work of an international team of astronomers on the paper, including Crossfield at KU and collaborators from the Max Planck Institute in Heidelberg, Germany, a cohort led by Laura Kreidberg, and investigators at the University of Texas, Austin, led by Caroline Morley.

Brande and his co-authors approached their analysis differently than previous efforts by focusing on determining the physical parameters of the small-Neptune atmospheres. In contrast, previous analyses often involved fitting a single model spectrum to observations.

“Typically, researchers would take an atmospheric model with pre-computed water content, scale and shift it to match observed planets in their sample,” Brande said. “This approach indicates whether the spectrum is clear or cloudy but provides no information about the amount of water vapor or the location of clouds in the atmosphere.”

Instead, Brande employed a technique known as “atmospheric retrieval.”

“This involved modeling the atmosphere across various planet parameters such as water vapor quantity and cloud location, iterating through hundreds and thousands of simulations to find the best fit configuration,” he said. “Our retrievals gave us a best-fit model spectrum for each planet, from which we calculated how cloudy or clear the planet appeared to be. Then, we compared those measured clarities to a separate suite of models by Caroline Morley, which let us see that our results are in line with expectations for similar planets. In examining cloud and haze behavior, our models indicated that clouds were a better fit than hazes. The sedimentation efficiency parameter, reflecting cloud compactness, suggested observed planets had relatively low sedimentation efficiencies, resulting in fluffy clouds. These clouds, made up of particles like water droplets, remained lofted in the atmosphere due to their low settling tendency.”

Brande’s findings provide insights into the behavior of these planetary atmospheres and caused “substantial interest” when he presented them at a recent meeting of the American Astronomical Society. Moreover, Brande is part of an international observation program, led by Crossfield, that just announced findings of water vapor on GJ 9827d — a planet as hot as Venus 97 light-years from Earth in the constellation Pisces. The observations, made with the Hubble Space Telescope, show the planet may be just one example of water-rich planets in the Milky Way. They were announced by a team led by Pierre-Alexis Roy of the Trottier Institute for Research on Exoplanets at Université de Montréal.

“We were searching for water vapor on the atmospheres of sub-Neptune-type planets,” Brande said. “Pierre-Alexis’ paper is the latest from that main effort because it took approximately 10 or 11 orbits or transits of the planet to make the water-vapor detection. Pierre-Alexis’ spectrum made it into our paper as one of our trend-data points, and we included all the planets from their proposal and others studied in the literature, making our results stronger. We were in close communication with them during the process of both papers to ensure we were using the proper updated results and accurately reflecting their findings.”

The TESS-Keck Survey. XVII. Precise Mass Measurements in a Young, High-multiplicity Transiting Planet System Using Radial Velocities and Transit Timing Variations

by Corey Beard, Paul Robertson, Fei Dai, et al in The Astronomical Journal

A recently discovered solar system with six confirmed exoplanets and a possible seventh is boosting astronomers’ knowledge of planet formation and evolution. Relying on a globe-spanning arsenal of observatories and instruments, a team led by researchers at the University of California, Irvine has compiled the most precise measurements yet of the exoplanets’ masses, orbital properties and atmospheric characteristics.

In a paper, the researchers share the results of the TESS-Keck Survey, providing a thorough description of the exoplanets orbiting TOI-1136, a dwarf star in the Milky Way galaxy more than 270 light years from Earth. The study is a follow-up to the team’s initial observation of the star and exoplanets in 2019 using data from the Transiting Exoplanet Survey Satellite. That project provided the first estimate of the exoplanets’ masses by clocking transit timing variations, a measure of the gravitational pull that orbiting planets exert on one another.

For the most recent study, the researchers joined TTV data with a radial velocity analysis of the star. Using the Automated Planet Finder telescope at the Lick Observatory on California’s Mount Hamilton and the High-Resolution Echelle Spectrometer at the W.M. Keck Observatory on Hawaii’s Mauna Kea, they could detect slight variations in stellar motion via the redshift and blueshift of the Doppler effect — which helped them determine planetary mass readings of unprecedented precision.

To obtain such exact information on the planets in this solar system, the team built computer models using hundreds of radial velocity measurements layered over TTV data. Lead author Corey Beard, a UCI Ph.D. candidate in physics, said that combining these two types of readings yielded more knowledge about the system than ever before.

“It took a lot of trial and error, but we were really happy with our results after developing one of the most complicated planetary system models in exoplanet literature to date,” Beard said.

The large number of planets is one factor that inspired the astronomy team to conduct further research, according to co-author Paul Robertson, UCI associate professor of physics & astronomy.

*Posterior transit fit to the single transit of the candidate planet.*

“We viewed TOI-1136 as being highly advantageous from a research standpoint, because when a system has multiple exoplanets, we can control for the effects of planet evolution that depend on the host star, and that helps us focus on individual physical mechanisms that led to these planets having the properties that they do,” he said.

Robertson added that when astronomers try to compare planets in separate solar systems, there are many variables that can differ based on the distinct properties of the stars and their locations in disparate parts of the galaxy. He said that looking at exoplanets in the same system enables the study of planets that have experienced a similar history.

By stellar standards, TOI-1136 is young, a mere 700 million years old, another feature that has attracted exoplanet hunters. Robertson said that juvenile stars are both “difficult and special” to work with because they’re so active. Magnetism, sunspots and solar flares are more prevalent and intense during this stage of a star’s development, and the resulting radiation blasts and sculpts planets, affecting their atmospheres.

TOI-1136’s confirmed exoplanets, TOI-1136 b through TOI-1136 g, are categorized as “sub-Neptunes” by the experts. Robertson said the smallest one is more than twice the radius of Earth, and others are up to four times Earth’s radius, comparable to the sizes of Uranus and Neptune. All these planets orbit TOI-1136 in less than the 88 days it takes Mercury to go around Earth’s sun, according to the study. “We’re packing an entire solar system into a region around the star so small that our entire planetary system here would be outside of it,” Robertson said.

“They’re weird planets to us because we don’t have anything exactly like them in our solar system,” said co-author Rae Holcomb, a UCI Ph.D. candidate in physics. “But the more we study other planet systems, it seems like they may be the most common type of planet in the galaxy.”

Another odd component to this solar system is the possible yet unconfirmed presence of a seventh planet. The researchers have detected some evidence of another resonant force in the system. Robertson explained that when planets are orbiting close to one another, they can pull on each other gravitationally.

“When you hear a chord played on a piano and it sounds good to you, it’s because there is resonance, or even spacing, between the notes that you’re hearing,” he said. “The orbital periods of these planets are spaced similarly. When the exoplanets are in resonance, the tugs are in the same direction every time. This can have a destabilizing effect, or in special cases, it can serve to make the orbits more stable.”

Robertson noted that far from answering all his team’s questions about the exoplanets in this system, the survey has made the researchers want to pursue additional knowledge, particularly about the composition of planetary atmospheres. That line of inquiry would be best approached through the advanced spectroscopy capabilities of NASA’s James Webb Space Telescope, he said.

“I am proud that both UCO’s Lick Observatory and the Keck Observatories were involved in the characterization of a really important system,” said Matthew Shetrone, deputy director of UC Observatories. “Having so many moderate-sized planets in the same system really lets us test formation scenarios. I really want to know more about these planets! Might we find a molten rock world, a water world and an ice world all in the same solar system? It almost feels like science fiction.”

Discovery of a Dust Sorting Process on Boulders Near the Reiner Gamma Swirl on the Moon

by Ottaviano Rüsch, Marcel Hess, Christian Wöhler, Valentin T. Bickel, Rachael M. Marshal, Markus Patzek, Hans L. F. Huybrighs in Journal of Geophysical Research: Planets

Our Earth’s Moon is almost completely covered in dust. Unlike on Earth, this dust is not smoothed by wind and weather, but is sharp-edged and also electrostatically charged. This dust has been studied since the Apollo era at the end of the 1960s. Now, an international research team led by Dr. Ottaviano Rüsch from the University of Münster has for the first time discovered anomalous meter-sized rocks on the lunar surface that are covered in dust and presumably exhibit unique properties — such as magnetic anomalies. The scientists’ most important finding is that only very few boulders on the Moon have a layer of dust with very special reflective properties. For example, the dust on these newly discovered boulders reflects sunlight differently than on previously known rocks. These new findings help scientists to understand the processes that form and change the lunar crust.

It is known that there are magnetic anomalies on the lunar surface, particularly near a region called Reiner Gamma. However, the question of whether rocks can be magnetic has never been investigated. “Current knowledge of the Moon’s magnetic properties is very limited, so these new rocks will shed light on the history of the Moon and its magnetic core,” says Ottaviano Rüsch from the ‘Institut für Planetologie’, categorizing the discovery. “For the first time, we have investigated the interactions of dust with rocks in the Reiner Gamma region — more precisely, the variations in the reflective properties of these rocks. For example, we can deduce to what extent and in which direction the sunlight is reflected by these large rocks.” The images were taken by NASA’s Lunar Reconnaissance Orbiter spacecraft, which orbits the Moon.

The research team was originally interested in cracked rocks. They first used artificial intelligence to search through around one million images for fractured rocks — these images were also taken by the Lunar Reconnaissance Orbiter. “Modern data processing methods allow us to gain completely new insights into global contexts — at the same time, we keep finding unknown objects in this way, such as the anomalous rocks that we are investigating in this new study,” says Valentin Bickel from the Center for Space and Habitability at the University of Bern. The search algorithm identified around 130,000 interesting rocks, half of which were scrutinized by the scientists.

The meter-high rocks discovered in the work are located near the Reiner K crater in the “Reiner Gamma” region, which has a magnetic anomaly.

“We recognized a boulder with distinctive dark areas on just one image. This rock was very different from all the others, as it scatters less light back towards the sun than other rocks. We suspect that this is due to the particular dust structure, such as the density and grain size of the dust,” Ottaviano Rüsch explains. “Normally, lunar dust is very porous and reflects a lot of light back in the direction of illumination. However, when the dust is compacted, the overall brightness usually increases. This is not the case with the observed dust-covered rocks,” adds Marcel Hess from TU Dortmund University.

This is a fascinating discovery — however, the scientists are still in the early stages of understanding this dust and its interactions with the rock. In the coming weeks and months, the scientists want to further investigate the processes that lead to the interactions between dust and rocks and to the formation of the special dust structure. These processes include, for example, the lifting of the dust due to electrostatic charging or the interaction of the solar wind with local magnetic fields.

In addition to numerous other international unmanned space missions to the Moon, NASA will be sending an automatic rover, a mobile robot, to the Reiner Gamma region in the coming years to find similar types of boulders with special dust. Even if it is still a dream of the future, a better understanding of dust movement can help with the planning of human settlements on the Moon, for example. After all, we know from the experience of the Apollo astronauts that dust poses many problems, such as the contamination of habitats (e.g., space stations) and technical equipment.

A pulsar in a binary with a compact object in the mass gap between neutron stars and black holes

by Ewan D. Barr, Arunima Dutta, et al in Science

An international team of astronomers have found a new and unknown object in the Milky Way that is heavier than the heaviest neutron stars known and yet simultaneously lighter than the lightest black holes known.

Using the MeerKAT Radio Telescope, astronomers from a number of institutions including The University of Manchester and the Max Planck Institute for Radio Astronomy in Germany found an object in orbit around a rapidly spinning millisecond pulsarlocated around 40,000 light years away in a dense group of stars known as a globular cluster.

Using the clock-like ticks from the millisecond pulsar they showed that the massive object lies in the so-called black hole mass gap. It could be the first discovery of the much-coveted radio pulsar — black hole binary; a stellar pairing that could allow new tests of Einstein’s general relativity and open doors to the study of black holes.

UK project lead Ben Stappers, Professor of Astrophysics at The University of Manchester, said: “Either possibility for the nature of the companion is exciting. A pulsar-black hole system will be an important target for testing theories of gravity and a heavy neutron star will provide new insights in nuclear physics at very high densities.”

When a neutron star — the ultra-dense remains of dead star — acquire too much mass, usually by consuming or colliding with another star, they will collapse. What they become after they collapse is the cause of much speculation, but it is believed that they could become black holes — objects so gravitationally attractive that even light cannot escape them.

Astronomers believe that the total mass required for a neutron star to collapse is 2.2 times the mass of the sun. Theory, backed by observation, tells us that the lightest black holes created by these stars are much larger, at about five times more massive than the Sun, giving rise to what is known as the ‘black hole mass gap’.

The nature of compact objects in this mass gap is unknown and detailed study has so far proved challenging. The discovery of the object may help finally understand these objects.

Prof Stappers, added: “The ability of the extremely sensitive MeerKAT telescope to reveal and study these objects is a enabling a great step forward and provides us with a glimpse of what will be possible with the Square Kilometre Array.”

The discovery of the object was made while observing a large cluster of stars known as NGC 1851 located in the southern constellation of Columba, using the MeerKAT telescope. The globular cluster NGC 1851 is a dense collection of old stars that are much more tightly packed than the stars in the rest of the Galaxy. Here, it is so crowded that the stars can interact with each other, disrupting orbits and in the most extreme cases colliding.

The astronomers, part of the international Transients and Pulsars with MeerKAT (TRAPUM) collaboration, believe that it is one such collision between two neutron stars that is proposed to have created the massive object that now orbits the radio pulsar. The team were able to detect faint pulses from one of the stars, identifying it as a radio pulsar — a type of neutron star that spins rapidly and shines beams of radio light into the Universe like a cosmic lighthouse.

The pulsar spins more than 170 times a second, with every rotation producing a rhythmic pulse, like the ticking of a clock. The ticking of these pulses is incredibly regular and by observing how the times of the ticks change, using a technique called pulsar timing, they were able to make extremely precise measurements of its orbital motion.

Ewan Barr from Max Planck Institute for Radio Astronomy, who led the study with his colleague Arunima Dutta, explained: “Think of it like being able to drop an almost perfect stopwatch into orbit around a star almost 40,000 light years away and then being able to time those orbits with microsecond precision.”

The regular timing also allowed a very precise measurement of the system’s location, showing that the object in orbit with the pulsar was no regular star but an extremely dense remnant of a collapsed star. Observations also showed that the companion has a mass that was simultaneously bigger than that of any known neutron star and yet smaller than that of any known black hole, placing it squarely in the black-hole mass gap.

While the team cannot conclusively say whether they have discovered the most massive neutron star known, the lightest black hole known or even some new exotic star variant, what is certain is that they have uncovered a unique laboratory for probing the properties of matter under the most extreme conditions in the Universe.

Arunima Dutta concludes: “We’re not done with this system yet. “Uncovering the true nature of the companion will a turning point in our understanding of neutron stars, black holes, and whatever else might be lurking in the black hole mass gap.”

Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433

by F. Aharonian, F. Ait Benkhali, J. Aschersleben, et al in Science

The science fiction author Arthur C. Clarke selected his own seven wonders of the world in a BBC television series in 1997. The only astronomical object he included was SS 433. It had attracted attention already in the late 1970s due to its X-ray emission and was later discovered to be at the center of a gas nebula that is dubbed the manatee nebula due to its unique shape resembling these aquatic mammals.

SS 433 is a binary star system in which a black hole, with a mass approximately ten times that of the Sun, and a star, with a similar mass but occupying a much larger volume, orbit each other with a period of 13 days. The intense gravitational field of the black hole rips material from the surface of the star, which accumulates in a hot gas disk that feeds the black hole. As matter falls in toward the black hole, two collimated jets of charged particles (plasma) are launched, perpendicular to the plane of the disk, at a quarter of the speed of light.

The jets of SS433 can be detected in the radio to x-ray ranges out to a distance of less than one light year either side of the central binary star, before they become too dim to be seen. Yet surprisingly, at around 75 light-years distance from their launch site, the jets are seen to abruptly reappear as bright X-ray sources. The reasons for this reappearance have long been poorly understood.

Similar relativistic jets are also observed emanating from the centers of active galaxies (for example quasars), though these jets are much larger in size than the galactic jets of SS 433. Due to this analogy, objects like SS 433 are classified as microquasars.

Until recently, no gamma ray emission has ever been detected from a microquasar. But this changed in 2018, when the High Altitude Water Cherenkov Gamma-ray Observatory (HAWC), for the first time, succeeded in detecting very-high-energy gamma rays from the jets of SS 433. This means that somewhere in the jets particles are accelerated to extreme energies. Despite decades of research, it is still unclear how or where particles are accelerated within astrophysical jets.

Artist’s impression of the SS 433 system, depicting the large-scale jets (blue) and the surrounding Manatee Nebula (red). The jets are initially observable only for a short dis-tance from the microquasar after launch — too small to be visible in this picture. The jets then travel undetected for a distance of approximately 80 light-years (25 parsecs) before un-dergoing a transformation, abruptly reappearing as bright sources of non-thermal emission (X-ray and gamma-ray). Particles are efficiently accelerated at this location, likely indicating the presence of a strong shock: a discontinuity in the medium capable of accelerating particles. Credit: Science Communication Lab for MPIK/H.E.S.S.

The study of gamma-ray emission from microquasars provides one crucial advantage: while the jets of SS 433 are 50 times smaller than those of the closest active galaxy (Centaurus A), SS 433 is located inside the Milky Way a thousand times closer to Earth. As a consequence, the apparent size of the jets of SS 433 in the sky is much larger and thus their properties are easier to study with the current generation of gamma-ray telescopes.

Prompted by the HAWC detection, the H.E.S.S. Observatory initiated an observation campaign of the SS 433 system. This campaign resulted in around 200 hours of data and a clear detection of gamma-ray emission from the jets of SS 433. The superior angular resolution of the H.E.S.S. telescopes in comparison to earlier measurements allowed the researchers to pinpoint the origin of the gamma-ray emission within the jets for the first time, yielding intriguing results:

While no gamma-ray emission is detected from the central binary region, emission abruptly appears in the outer jets at a distance of about 75 light years either side of the binary star, in accordance to previous X-ray observations. However, what surprised the astronomers most, was a shift in the position of the gamma-ray emission when viewed at different energies.

The gamma-ray photons with the highest energies of more than 10 teraelectron-volts, are only detected at the point where the jets abruptly reappear (see fig 2c). By contrast, the regions emitting gamma rays with lower energies appear further along each jet.

“This is the first-ever observation of energy-dependent morphology in the gamma-ray emission of an astrophysical jet,” remarks Laura Olivera-Nieto, from the Max-Planck-Institut für Kernphysik in Heidelberg, who was leading the H.E.S.S. study of SS 433 as part of her doctoral thesis. “We were initially puzzled by these findings. The concentration of such high energy photons at the sites of the X-ray jets’ reappearance means efficient particle acceleration must be taking place there, which was not expected.”

The scientists did a simulation of the observed energy-dependence of the gammy-ray emission and were able to achieve the first-ever estimate of the velocity of the outer jets. The difference between this velocity and the one with which the jets are launched suggests that the mechanism which accelerated the particles further out is a strong shock- a sharp transition in the properties of the medium. The presence of a shock would then also provide a natural explanation for the x-ray reappearance of the jets, as accelerated electrons also produce x-ray radiation.

“When these fast particles then collide with a light particle (photon), they transfer part of their energy — which is how they produce the high-energy gamma photons observed with H.E.S.S. This process is called the inverse Compton effect,” explains Brian Reville, group leader of the Astrophysical Plasma Theory group at the Max Planck Institute for Nuclear Physics in Heidelberg.
“There has been a great deal of speculation about the occurrence of particle acceleration in this unique system — not anymore: the H.E.S.S. result really pins down the site of acceleration, the nature of the accelerated particles, and allows us to probe the motion of the large-scale jets launched by the black hole” points-out Jim Hinton, Director of the Max Planck Institute for Nuclear Physics in Heidelberg and Head of the Non-thermal Astrophysics Department.
“Just a few years ago, it was unthinkable that ground-based gamma-ray measurements could provide information about the internal dynamics of such a system” adds coauthor Michelle Tsirou, a postdoctoral researcher at DESY Zeuthen.

However, nothing is known about the origin of the shocks at the sites where the jet reappears. “We still don’t have a model that can uniformly explain all the properties of the jet, as no model has yet predicted this feature” explains Olivera-Nieto. She wants to devote herself to this task next — a worthwhile goal, as the relative proximity of SS 433 to Earth offers a unique opportunity to study the occurrence of particle acceleration in relativistic jets. It is hoped that the results can be transferred to the thousand-times larger jets of active galaxies and quasars, which would help solve the many puzzles concerning the origin of the most energetic cosmic rays.

First Emulsion γ-Ray Telescope Imaging of the Vela Pulsar by the GRAINE 2018 Balloon-borne Experiment

by Satoru Takahashi, Shigeki Aoki, Atsushi Iyono, et al in The Astrophysical Journal

A pancake stack of radioactivity-sensitive films carried through the sky by a balloon was able to take the world’s most accurate picture of a neutron star’s gamma ray beam. To achieve this, Kobe University researchers combined the oldest method of capturing radioactive radiation with the newest data capturing techniques and a clever time-recording device.

The stars shine their light on us in the full range of the spectrum of light, from infra-red to gamma rays. For each of these bands, different sensing equipment is needed. The most challenging one is gamma rays, famous for being a high-energy product of nuclear fission, because their very short wavelength means that they don’t interact with matter in the same way as other forms of light and thus can’t be deflected with lenses or detected by standard sensors. Thus, there is a gap in our ability to detect the light coming from fascinating stellar objects such as supernovae and their remnants.

To resolve this issue, Kobe University astrophysicist AOKI Shigeki and his team turned to the very first material that was used to detect radioactivity, photographic films. “Our group has been focusing on the excellent capability of emulsion film to trace gamma rays with high precision and proposed that it could become an excellent gamma-ray telescope by introducing several modern data capture and analysis features,” explains Aoki. Based on the high sensitivity of these films and a novel, automated, high-speed process of extracting data from them, the physicists’ idea was to stack up a few of them to accurately capture the trajectory of the particles that the gamma ray produces on impact, just like a single pancake may capture where you poke a straw into it, but it takes a whole stack to record the straw’s direction.

Schematic view of the emulsion γ-ray telescope.

To reduce atmospheric interference, they then mounted the stack of films onto a scientific observation balloon to lift it to a height between 35 and 40 kilometers. However, since a balloon is swaying and twisting in the wind, the direction of the “telescope” is not stable, so they added a set of cameras to record the gondola’s orientation relative to the stars at any time. But this created another issue, because as anybody who has ever taken a photograph with long exposure knows, photographic film does not record the passage of time and so it is not directly possible to know at what time any given gamma ray impact occurred. To overcome this problem, they made the bottom three layers of film move back and forth at regular but different speeds, just like the hands of a clock. From the relative dislocation of the traces in those lower plates they could then calculate the precise time of the impact and thus correlate it with the cameras’ footage.

They have now published the first image resulting from this setup. It is the most accurate image ever produced of the Vela pulsar, a fast-spinning neutron star that projects a beam of gamma rays into the sky like a lighthouse at night.

“We captured a total of several trillion tracks with an accuracy of 1/10,000 millimeters. By adding time information and combining it with attitude monitoring information, we were able to determine ‘when’ and ‘where’ the events originated with such precision that the resulting resolution was more than 40 times higher than that of conventional gamma-ray telescopes,” Aoki summarizes his group’s achievements.

While these results are impressive already, the new technique opens the possibility of capturing more details in this frequency band of light than ever before. The Kobe University researcher explains,

“By means of scientific balloon-borne experiments, we can attempt to contribute to many areas of astrophysics, and in particular to open up gamma-ray telescopy to ‘multi-messenger astronomy’ where simultaneous measurements of the same event captured through different techniques are required. Based on the success of the 2018 balloon experiment these data were generated with, we will expand the observation area and time in upcoming balloon flights and are looking forward to scientific breakthroughs in the field of gamma-ray astronomy.”

The dark matter profile of the Milky Way inferred from its circular velocity curve

by Xiaowei Ou, Anna-Christina Eilers, Lina Necib, Anna Frebel in Monthly Notices of the Royal Astronomical Society

By clocking the speed of stars throughout the Milky Way galaxy, MIT physicists have found that stars further out in the galactic disk are traveling more slowly than expected compared to stars that are closer to the galaxy’s center. The findings raise a surprising possibility: The Milky Way’s gravitational core may be lighter in mass, and contain less dark matter, than previously thought.

The new results are based on the team’s analysis of data taken by the Gaia and APOGEE instruments. Gaia is an orbiting space telescope that tracks the precise location, distance, and motion of more than 1 billion stars throughout the Milky Way galaxy, while APOGEE is a ground-based survey. The physicists analyzed Gaia’s measurements of more than 33,000 stars, including some of the farthest stars in the galaxy, and determined each star’s “circular velocity,” or how fast a star is circling in the galactic disk, given the star’s distance from the galaxy’s center.

The scientists plotted each star’s velocity against its distance to generate a rotation curve — a standard graph in astronomy that represents how fast matter rotates at a given distance from the center of a galaxy. The shape of this curve can give scientists an idea of how much visible and dark matter is distributed throughout a galaxy.

“What we were really surprised to see was that this curve remained flat, flat, flat out to a certain distance, and then it started tanking,” says Lina Necib, assistant professor of physics at MIT. “This means the outer stars are rotating a little slower than expected, which is a very surprising result.”

The team translated the new rotation curve into a distribution of dark matter that could explain the outer stars’ slow-down, and found the resulting map produced a lighter galactic core than expected. That is, the center of the Milky Way may be less dense, with less dark matter, than scientists have thought.

“This puts this result in tension with other measurements,” Necib says. “There is something fishy going on somewhere, and it’s really exciting to figure out where that is, to really have a coherent picture of the Milky Way.”

Comparison between the Gaia astrometric parallax (⁠⁠) and our predicted spectrophotometric parallaxes (⁠⁠).

Like most galaxies in the universe, the Milky Way spins like water in a whirlpool, and its rotation is driven, in part, by all the matter that swirls within its disk. In the 1970s, astronomer Vera Rubin was the first to observe that galaxies rotate in ways that cannot be driven purely by visible matter. She and her colleagues measured the circular velocity of stars and found that the resulting rotation curves were surprisingly flat. That is, the velocity of stars remained the same throughout a galaxy, rather than dropping off with distance. They concluded that some other type of invisible matter must be acting on distant stars to give them an added push.

Rubin’s work in rotation curves was one of the first strong pieces of evidence for the existence of dark matter — an invisible, unknown entity that is estimated to outweigh all the stars and other visible matter in the universe. Since then, astronomers have observed similar flat curves in far-off galaxies, further supporting dark matter’s presence. Only recently have astronomers attempted to chart the rotation curve in our own galaxy with stars.

“It turns out it’s harder to measure a rotation curve when you’re sitting inside a galaxy,” Ou notes.

In 2019, Anna-Christina Eilers, assistant professor of physics at MIT, worked to chart the Milky Way’s rotation curve, using an earlier batch of data released by the Gaia satellite. That data release included stars as far out as 25 kiloparsecs, or about 81,000 light years, from the galaxy’s center. Based on these data, Eilers observed that the Milky Way’s rotation curve appeared to be flat, albeit with mild decline, similar to other far-off galaxies, and by inference, the galaxy likely bore a high density of dark matter at its core. But this view now shifted, as the telescope released a new batch of data, this time including stars as far out as 30 kiloparsecs — almost 100,000 light years from the galaxy’s core.

“At these distances, we’re right at the edge of the galaxy where stars start to peter out,” Frebel says. “No one had explored how matter moves around in this outer galaxy, where we’re really in the nothingness.”

Frebel, Necib, Ou, and Eilers jumped on Gaia’s new data, looking to expand on Eilers’ initial rotation curve. To refine their analysis, the team complemented Gaia’s data with measurements by APOGEE — the Apache Point Observatory Galactic Evolution Experiment, which measures extremely detailed properties of more than 700,000 stars in the Milky Way, such as their brightness, temperature, and elemental composition.

“We feed all this information into an algorithm to try to learn connections that can then give us better estimates of a star’s distance,” Ou explains. “That’s how we can push out to farther distances.”

The team established the precise distances for more than 33,000 stars and used these measurements to generate a three-dimensional map of the stars scattered across the Milky Way out to about 30 kiloparsecs. They then incorporated this map into a model of circular velocity, to simulate how fast any one star must be traveling, given the distribution of all the other stars in the galaxy. They then plotted each star’s velocity and distance on a chart to produce an updated rotation curve of the Milky Way.

“That’s where the weirdness came in,” Necib says.

Instead of seeing a mild decline like previous rotation curves, the team observed that the new curve dipped more strongly than expected at the outer end. This unexpected downturn suggests that while stars may travel just as fast out to a certain distance, they suddenly slow down at the farthest distances. Stars at the outskirts appear to travel more slowly than expected. When the team translated this rotation curve to the amount of dark matter that must exist throughout the galaxy, they found that the Milky Way’s core may contain less dark matter than previously estimated.

“This result is in tension with other measurements,” Necib says. “Really understanding this result will have deep repercussions. This might lead to more hidden masses just beyond the edge of the galactic disk, or a reconsideration of the state of equilibrium of our galaxy. We seek to find these answers in upcoming work, using high resolution simulations of Milky Way-like galaxies.”

Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets

by Amaury H. M. J. Triaud, Julien de Wit, Frieder Klein, Martin Turbet, Benjamin V. Rackham, Prajwal Niraula, Ana Glidden, Oliver E. Jagoutz, Matej Peč, Janusz J. Petkowski, Sara Seager, Franck Selsis in Nature Astronomy

Scientists at MIT, the University of Birmingham, and elsewhere say that astronomers’ best chance of finding liquid water, and even life on other planets, is to look for the absence, rather than the presence, of a chemical feature in their atmospheres.

The researchers propose that if a terrestrial planet has substantially less carbon dioxide in its atmosphere compared to other planets in the same system, it could be a sign of liquid water — and possibly life — on that planet’s surface. What’s more, this new signature is within the sights of NASA’s James Webb Space Telescope (JWST). While scientists have proposed other signs of habitability, those features are challenging if not impossible to measure with current technologies. The team says this new signature, of relatively depleted carbon dioxide, is the only sign of habitability that is detectable now.

“The Holy Grail in exoplanet science is to look for habitable worlds, and the presence of life, but all the features that have been talked about so far have been beyond the reach of the newest observatories,” says Julien de Wit, assistant professor of planetary sciences at MIT. “Now we have a way to find out if there’s liquid water on another planet. And it’s something we can get to in the next few years.”

Astronomers have so far detected more than 5,200 worlds beyond our solar system. With current telescopes, astronomers can directly measure a planet’s distance to its star and the time it takes it to complete an orbit. Those measurements can help scientists infer whether a planet is within a habitable zone. But there’s been no way to directly confirm whether a planet is indeed habitable, meaning that liquid water exists on its surface.

Across our own solar system, scientists can detect the presence of liquid oceans by observing “glints” — flashes of sunlight that reflect off liquid surfaces. These glints, or specular reflections, have been observed, for instance, on Saturn’s largest moon, Titan, which helped to confirm the moon’s large lakes. Detecting a similar glimmer in far-off planets, however, is out of reach with current technologies. But de Wit and his colleagues realized there’s another habitable feature close to home that could be detectable in distant worlds.

“An idea came to us, by looking at what’s going on with the terrestrial planets in our own system,” Triaud says.

Venus, Earth, and Mars share similarities, in that all three are rocky and inhabit a relatively temperate region with respect to the sun. Earth is the only planet among the trio that currently hosts liquid water. And the team noted another obvious distinction: Earth has significantly less carbon dioxide in its atmosphere.

“We assume that these planets were created in a similar fashion, and if we see one planet with much less carbon now, it must have gone somewhere,” Triaud says. “The only process that could remove that much carbon from an atmosphere is a strong water cycle involving oceans of liquid water.”

Indeed, the Earth’s oceans have played a major and sustained role in absorbing carbon dioxide. Over hundreds of millions of years, the oceans have taken up a huge amount of carbon dioxide, nearly equal to the amount that persists in Venus’ atmosphere today. This planetary-scale effect has left Earth’s atmosphere significantly depleted of carbon dioxide compared to its planetary neighbors.

“On Earth, much of the atmospheric carbon dioxide has been sequestered in seawater and solid rock over geological timescales, which has helped to regulate climate and habitability for billions of years,” says study co-author Frieder Klein.

The team reasoned that if a similar depletion of carbon dioxide were detected in a far-off planet, relative to its neighbors, this would be a reliable signal of liquid oceans and life on its surface.

“After reviewing extensively the literature of many fields from biology, to chemistry, and even carbon sequestration in the context of climate change, we believe that indeed if we detect carbon depletion, it has a good chance of being a strong sign of liquid water and/or life,” de Wit says.

In their study, the team lays out a strategy for detecting habitable planets by searching for a signature of depleted carbon dioxide. Such a search would work best for “peas-in-a-pod” systems, in which multiple terrestrial planets, all about the same size, orbit relatively close to each other, similar to our own solar system. The first step the team proposes is to confirm that the planets have atmospheres, by simply looking for the presence of carbon dioxide, which is expected to dominate most planetary atmospheres.

“Carbon dioxide is a very strong absorber in the infrared, and can be easily detected in the atmospheres of exoplanets,” de Wit explains. “A signal of carbon dioxide can then reveal the presence of exoplanet atmospheres.”

Once astronomers determine that multiple planets in a system host atmospheres, they can move on to measure their carbon dioxide content, to see whether one planet has significantly less than the others. If so, the planet is likely habitable, meaning that it hosts significant bodies of liquid water on its surface. But habitable conditions doesn’t necessarily mean that a planet is inhabited. To see whether life might actually exist, the team proposes that astronomers look for another feature in a planet’s atmosphere: ozone.

On Earth, the researchers note that plants and some microbes contribute to drawing carbon dioxide, although not nearly as much as the oceans. Nevertheless, as part of this process, the lifeforms emit oxygen, which reacts with the sun’s photons to transform into ozone — a molecule that is far easier to detect than oxygen itself. The researchers say that if a planet’s atmosphere shows signs of both ozone and depleted carbon dioxide, it likely is a habitable, and inhabited world.

“If we see ozone, chances are pretty high that it’s connected to carbon dioxide being consumed by life,” Triaud says. “And if it’s life, it’s glorious life. It would not be just a few bacteria. It would be a planetary-scale biomass that’s able to process a huge amount of carbon, and interact with it.”

The team estimates that NASA’s James Webb Space Telescope would be able to measure carbon dioxide, and possibly ozone, in nearby, multiplanet systems such as TRAPPIST-1 — a seven-planet system that orbits a bright star, just 40 light years from Earth.

“TRAPPIST-1 is one of only a handful of systems where we could do terrestrial atmospheric studies with JWST,” de Wit says. “Now we have a roadmap for finding habitable planets. If we all work together, paradigm-shifting discoveries could be done within the next few years.”