It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Wednesday, March 05, 2025
SPACE/COSMOS
Gemini South observes ultra-hot nova erupting with surprising chemical signature
Astronomers uncover extremely hot and violent eruption from first ever near-infrared analysis of a recurrent nova outside of the Milky Way Galaxy
Association of Universities for Research in Astronomy (AURA)
This artist's illustration depicts an extragalactic nova eruption. Nova explosions occur in binary star systems in which a white dwarf — the dense remnant of a dead star — continually siphons stellar material from a nearby companion star. As the outer atmosphere of the companion gathers onto the surface of the white dwarf it reaches temperatures hot enough to spark an eruption. Almost all novae discovered to-date have been observed to erupt only once. But a few have been observed to erupt more than once, and are classified as recurrent novae. The span between eruptions for these novae can vary from as little as one year to many decades.
Credit: International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick, M. Zamani
Nova explosions occur in binary star systems in which a white dwarf — the dense remnant of a dead star — continually siphons stellar material from a nearby companion star. As the outer atmosphere of the companion gathers onto the surface of the white dwarf it reaches temperatures hot enough to spark an eruption.
Almost all novae discovered to-date have been observed to erupt only once. But a few have been observed to erupt more than once, and are classified as recurrent novae. The span between eruptions for these novae can vary from as little as one year to many decades [1].
Less than a dozen recurrent novae have been observed within our Milky Way Galaxy, while far more are extragalactic, meaning located outside of the Milky Way. Studying extragalactic novae helps build astronomers’ understanding of how different environments affect nova eruptions.
The first recurrent extragalactic nova to be observed was LMC 1968-12a (LMC68), located in the Large Magellanic Cloud — a satellite galaxy of the Milky Way. This nova has a recurrent timescale of about four years — the third-shortest of any nova — and consists of a white dwarf and a companion red subgiant (a star much larger than the Sun). It was discovered in 1968 and its eruptions have been observed fairly regularly since 1990.
Its most recent eruption, in August 2024, was first captured by the Neil Gehrels Swift Observatory, which has been closely monitoring the nova every month since its 2020 eruption. Given its known recurrent timescale, astronomers were anticipating this eruption, and LMC68 delivered right on cue.
Follow-up observations were conducted nine days after the initial outburst with the Carnegie Institution’s Magellan Baade Telescope, and 22 days after the initial outburst with the Gemini South telescope, one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab.
Using the technique of spectroscopy[2], the team observed LMC68’s near-infrared light, which allowed them to study the nova’s ultra-hot phase during which many elements have been highly energized. By studying this phase astronomers can learn about the most extreme processes at play in the eruption. This study is the first ever near-infrared spectroscopic observation of an extragalactic recurrent nova.
After its initial eruption LMC68’s light faded rapidly, but Gemini South’s FLAMINGOS-2 instrument still captured a strong signal from ionizedsilicon atoms, specifically silicon atoms that have been stripped of nine of their 14 electrons, which requires incredible amounts of energy in the form of radiation or violent collisions.
In the earlier spectrum from Magellan, the near-infrared light from just the ionized silicon alone shined 95 times brighter than the light emitted by the Sun added up across all its wavelengths (X-ray, ultraviolet, visible, infrared, and radio). When Gemini observed the line several days later the signal had faded, but the silicon emission still dominated the spectrum.
“The ionized silicon shining at almost 100 times brighter than the Sun is unprecedented,” says Tom Geballe, NOIRLab emeritus astronomer and co-author of the paper appearing in the Monthly Notices of the Royal Astronomical Society. “And while this signal is shocking, it’s also shocking what’s not there.”
Novae found in the Milky Way typically emit numerous near-infrared signatures from highly-excited elements, but LMC68’s spectra contained only the ionized silicon feature. “We would’ve expected to also see signatures of highly energized sulfur, phosphorus, calcium and aluminum,” says Geballe.
“This surprising absence, combined with the presence and great strength of the silicon signature, implied an unusually high gas temperature, which our modeling confirmed,” adds co-author Sumner Starrfield, Regents Professor of Astrophysics at Arizona State University.
The team estimates that, during the nova’s early post-explosion phase, the temperature of the expelled gas reached 3 million degrees Celsius (5.4 million degrees Fahrenheit), making it one of the hottest novae ever recorded. This extreme temperature suggests a highly violent eruption, which the team theorizes is due to the conditions of the nova’s environment.
The Large Magellanic Cloud and its stars have a lower metallicity than the Milky Way, meaning it contains a lower abundance of elements heavier than hydrogen and helium, referred to as metals by astronomers. In high-metallicity systems, heavy elements trap heat on the white dwarf’s surface such that eruptions occur early in the accretion process. But without these heavy elements, more matter builds up on the white dwarf’s surface before it gets hot enough to ignite, causing the explosion to erupt with far greater violence. Additionally, the expelled gas collides with the atmosphere of the companion red subgiant, causing a huge shock that elevates the temperatures in the collision.
Prior to collecting their data, Starrfield predicted that the accretion of low-metallicity material onto a white dwarf would result in a more violent nova explosion. The observations and analysis presented here are broadly in agreement with that prediction.
“With only a small number of recurrent novae detected within our own galaxy, understanding of these objects has progressed episodically,” says Martin Still, NSF program director for the International Gemini Observatory. “By broadening our range to other galaxies using the largest astronomical telescopes available, like Gemini South, astronomers will increase the rate of progress and critically measure the behavior of these objects in different chemical environments.”
Notes
[1] With a recurrence period of about one year, M31N 2008-12a has the shortest time interval between eruptions of any recurrent nova, while the longest is V2487 Ophiuchi with a recurrence period of 98 years.
[2] Spectroscopy involves capturing the light of an object and spreading it out into a spectrum, which allows scientists to identify the chemical elements present in the object via the specific wavelengths of light they emit.
More information
This research was presented in a paper titled “Near-infrared spectroscopy of the LMC recurrent nova LMCN 1968-12a” appearing in the Monthly Notices of the Royal Astronomical Society. DOI: 10.1093/mnras/stae2711
The team is composed of A. Evans (Keele University), D. P. K. Banerjee (Physical Research Laboratory, Ahmedabad), T. R. Geballe (International Gemini Observatory/NSF NOIRLab), A. Polin (Purdue University), E. Y. Hsiao (Florida State University), K. L. Page (University of Leicester), C. E. Woodward (University of Minnesota), S. Starrfield (Arizona State University).
The scientific community is honored to have the opportunity to conduct astronomical research on I’oligam Du’ag (Kitt Peak) in Arizona, on Maunakea in Hawai‘i, and on Cerro Tololo and Cerro Pachón in Chile. We recognize and acknowledge the very significant cultural role and reverence of I’oligam Du’ag to the Tohono O’odham Nation, and Maunakea to the Kanaka Maoli (Native Hawaiians) community.
This graph shows the near-infrared spectra of LMC68, obtained 8.58 days after the eruption with the Carnegie Institution’s Magellan Baade Telescope (black), and 22.49 days after with the Gemini South telescope (red), one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab. The ionizedsilicon emission around 1.4 microns dominates both spectra. Apparent emission features around 1.8-2 microns are a result of contamination from Earth’s atmosphere.
This graph is adapted from Figure 2 in the paper titled “Near-infrared spectroscopy of the LMC recurrent nova LMCN 1968-12a” appearing in the Monthly Notices of the Royal Astronomical Society.
Credit
International Gemini Observatory/NOIRLab/NSF/AURA/T. Geballe/J. Pollard
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Neural network deciphers gravitational waves from merging neutron stars in a second
Machine learning method could revolutionize multi-messenger astronomy
Image: Artist impression of a binary neutron star merger, emitting gravitational waves and electromagnetic radiation. Detection and analysis of these signals can provide profound insights into the underlying processes.
Binary neutron star mergers occur millions of light-years away from Earth. Interpreting the gravitational waves they produce presents a major challenge for traditional data-analysis methods. These signals correspond to minutes of data from current detectors and potentially hours to days of data from future observatories. Analyzing such massive data sets is computationally expensive and time-consuming.
An international team of scientists has developed a machine learning algorithm, called DINGO-BNS (Deep INference for Gravitational-wave Observations from Binary Neutron Stars) that saves valuable time in interpreting gravitational waves emitted by binary neutron star mergers. They trained a neural network to fully characterize systems of merging neutron stars in about a second, compared to about an hour for the fastest traditional methods. Their results will be published in Nature on March 5, 2025, under the title “Real-time inference for binary neutron star mergers using machine learning”.
Why is real-time computation important?
Neutron star mergers emit visible light (in the subsequent kilonova explosion) and other electromagnetic radiation in addition to gravitational waves, as shown in this video. “Rapid and accurate analysis of the gravitational-wave data is crucial to localize the source and point telescopes in the right direction as quickly as possible to observe all the accompanying signals,” says the first author of the publication, Maximilian Dax, who is a Ph.D. student in the Empirical Inference Department at the Max Planck Institute for Intelligent Systems (MPI-IS), at ETH Zurich and at the ELLIS Institute Tübingen.
The real-time method could set a new standard for data analysis of neutron star mergers, giving the broader astronomy community more time to point their telescopes toward the merging neutron stars as soon as the large detectors of the LIGO-Virgo-KAGRA (LVK) collaboration identify them.
“Current rapid analysis algorithms used by the LVK make approximations that sacrifice accuracy. Our new study addresses these shortcomings,” says Jonathan Gair, a group leader in the Astrophysical and Cosmological Relativity Department at the Max Planck Institute for Gravitational Physics in the Potsdam Science Park.
Indeed, the machine learning framework fully characterizes the neutron star merger (e.g., its masses, spins, and location) in just one second without making such approximations. This allows, among other things, to quickly determine the sky position 30% more precisely. Because it works so quickly and accurately, the neural network can provide critical information for joint observations of gravitational-wave detectors and other telescopes. It can help to search for the light and other electromagnetic signals produced by the merger and to make the best possible use of the expensive telescope observing time.
Catching a neutron star merger in the act
“Gravitational wave analysis is particularly challenging for binary neutron stars, so for DINGO-BNS, we had to develop various technical innovations. This includes for example a method for event-adaptive data compression,” says Stephen Green, UKRI Future Leaders Fellow at the University of Nottingham. Bernhard Schölkopf, Director of the Empirical Inference Department at MPI-IS and at the ELLIS Institute Tübingen, adds: “Our study showcases the effectiveness of combining modern machine learning methods with physical domain knowledge.”
DINGO-BNS could one day help to observe electromagnetic signals before and at the time of the collision of the two neutron stars. “Such early multi-messenger observations could provide new insights into the merger process and the subsequent kilonova, which are still mysterious,” says Alessandra Buonanno, Director of the Astrophysical and Cosmological Relativity Department at the Max Planck Institute for Gravitational Physics.
This artist's concept depicts one of the possible scenarios for the 148780 Altjira system in the solar system's Kuiper Belt. It is likely a hierarchical triple formation, in which two very close companions are orbited by a third member at a greater distance.
The inner bodies are too close together to be resolved by the Hubble Space Telescope. But Hubble observations of the orbit of the outermost object were used to determine that the central body is not a single spherical object. Other possibilities are that the inner object is a contact binary, where two separate bodies become so close they touch each other. Another idea is that the central body is oddly flat, like a pancake. Of the 40 identified binary objects in the Kuiper Belt, another system, Lempo, has been found to be a triple.
The Altjira system is located in the outer reaches of the solar system, 3.7 billion miles away, or 44 times the distance between Earth and the Sun. In this artist's concept, our Sun is in the constellation Sagittarius, with the Milky Way in the background. The bright red star Antares appears at the top center. Dust in the plane of our solar system glows as zodiacal light.
The puzzle of predicting how three gravitationally bound bodies move in space has challenged mathematicians for centuries, and has most recently been popularized in the novel and television show "3 Body Problem." There's no problem, however, with what a team of researchers say is likely a stable trio of icy space rocks in the solar system's Kuiper Belt, found using data from NASA's Hubble Space Telescope and the ground-based W. M. Keck Observatory in Hawaii.
If confirmed as the second such three-body system found in the region, the 148780 Altjira system suggests there could be similar triples waiting to be discovered, which would support a particular theory of our solar system's history and the formation of Kuiper Belt objects (KBOs).
"The universe is filled with a range of three-body systems, including the closest stars to Earth, the Alpha Centauri star system, and we're finding that the Kuiper Belt may be no exception," said the study's lead author Maia Nelsen, a physics and astronomy graduate of Brigham Young University in Provo, Utah.
Known since 1992, KBOs are primitive icy remnants from the early solar system found beyond the orbit of Neptune. To date, over 3,000 KBOs have been cataloged, and scientists estimate there could be several hundred thousand more that measure over 10 miles in diameter. The largest KBO is dwarf planet Pluto.
The Hubble finding is crucial support for a KBO formation theory, in which three small rocky bodies would not be the result of collision in a busy Kuiper Belt, but instead form as a trio directly from the gravitational collapse of matter in the disk of material surrounding the newly formed Sun, around 4.5 billion years ago. It's well known that stars form by gravitational collapse of gas, commonly as pairs or triples, but that idea that cosmic objects like those in the Kuiper Belt form in a similar way is still under investigation.
The Altjira system is located in the outer reaches of the solar system, 3.7 billion miles away, or 44 times the distance between Earth and the Sun. Hubble images show two KBOs located about 4,700 miles (7,600 kilometers) apart. However, researchers say that repeated observations of the objects' unique co-orbital motion indicate the inner object is actually two bodies that are so close together they can't be distinguished at such a great distance.
"With objects this small and far away, the separation between the two inner members of the system is a fraction of a pixel on Hubble's camera, so you have to use non-imaging methods to discover that it's a triple," said Nelsen.
This takes time and patience, Nelsen explained. Scientists have gathered a 17-year observational baseline of data from Hubble and the Keck Observatory, watching the orbit of the Altjira system's outer object.
"Over time, we saw the orientation of the outer object's orbit change, indicating that the inner object was either very elongated or actually two separate objects," said Darin Ragozzine, also of Brigham Young University, a co-author of the Altjira study.
"A triple system was the best fit when we put the Hubble data into different modeling scenarios," said Nelsen. "Other possibilities are that the inner object is a contact binary, where two separate bodies become so close they touch each other, or something that actually is oddly flat, like a pancake."
Currently, there are about 40 identified binary objects in the Kuiper Belt. Now, with two of these systems likely triples, the researchers say it is more likely they are looking not at an oddball, but instead a population of three-body systems, formed by the same circumstances. However, building up that evidence takes time and repeated observations.
The only Kuiper Belt objects that have been explored in detail are Pluto and the smaller object Arrokoth, which NASA's New Horizons mission visited in 2015 and 2019, respectively. New Horizons showed that Arrokoth is a contact binary, which for KBOs means that two objects that have moved closer and closer to one another are now touching and/or have merged, often resulting in a peanut shape. Ragozzine describes Altjira as a "cousin" of Arrokoth, a member of the same group of Kuiper Belt objects. They estimate Altjira is 10 times larger than Arrokoth, however, at 124 miles (200 kilometers) wide.
While there is no mission planned to fly by Altjira to get Arrokoth-level detail, Nelsen said there is a different upcoming opportunity for further study of the intriguing system. "Altjira has entered an eclipsing season, where the outer body passes in front of the central body. This will last for the next ten years, giving scientists a great opportunity to learn more about it," Nelsen said. NASA's James Webb Space Telescope is also joining in on the study of Altjira as it will check if the components look the same in its upcoming Cycle 3 observations.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Scientists from UNSW Sydney have located a potential new exoplanet – a planet that orbits a star outside of our solar system – using a technique known as ‘transit timing variation’.
In research highlighted in a new paper, published today in The Astrophysical Journal,Scientia Senior Lecturer Ben Montet and PhD candidate Brendan McKee analysed changes in the timing of a known planet’s transit across its star, to infer the presence of a second exoplanet.
After identifying an unusual trend in the movement of the hot Jupiter planet TOI-2818b, the team, from the UNSW School of Physics, ran a series of model simulations that pointed to the presence of a small planetary companion to the known hot Jupiter.
The new exoplanet is estimated to be 10-16 times the size of Earth, with a predicted orbital period less than 16 days.
"It’s rare for hot Jupiters to have other planets near them,” says Dr Montet. “So this new planet could have implications about how hot Jupiters form and in turn, help us to understand other solar systems.”
Hunting for exoplanets
An exoplanet is any planet outside of our own solar system. Like the planets in our solar system orbit the sun, most exoplanets also orbit a star.
To date there are over 5500 known exoplanets confirmed by NASA, with trillions more predicted to exist within the Milky Way galaxy. Of the known exoplanets, there are approximately 500 known hot Jupiters – hot, gaseous exoplanets. Even lesser-known are companion planets to hot Jupiters – planets that orbit the same star as a hot Jupiter.
One method for hunting exoplanets, known as Transit Timing Variation (TTV), uses the movement of planets around their stars, which can affect the signal for the star’s brightness.
“The planet passes in front of its star from where we see it on Earth, a bit like an eclipse, and it blocks some of its light,” says Mr McKee. “And our records will show that the light emitted from the star will dip for a few hours as the planet travels in front of it. And we see those dips every single time a planet orbits.”
Dr Montet describes the occurrence as like “the planet casting a shadow on the star, so it appears a little fainter”.
Planets make good clocks, and an exoplanet's orbit around a star should remain stable, ensuring consistent timing between transits. “But if you have more than one planet at play, then the planets will pull each other with their gravity and make each other speed up and slow down a little bit,” says Dr Montet. “This means the transits will arrive slightly earlier or later than normal, and you can use that to infer that another planet's causing these timing variations.”
Modelling planetary movements
To start, Mr McKee went through three years of data from the TESS telescope, (Transiting Exoplanet Survey Satellite).
One known exoplanet is TOI-2818b, orbiting a star visible with a standard telescope located just over 1000 light-years away in the constellation Puppis. TOI-2818b, a hot Jupiter, was discovered via its transits. However, when analysing the data, Mr McKee noticed that its transit dips were not evenly spaced – they were occurring closer together over time.
If this planet were a clock, it wasn’t keeping accurate time. Something was influencing its orbit, prompting Mr McKee and Dr Montet to investigate the mystery.
“The tricky thing is that there are a number of plausible explanations for why the planet is arriving early,” says Mr McKee.
For example, the tides of a star can impact the gravitational pull on a planet, just like we see between the Moon and the Earth. When this is the case, the planet is typically spiraling inwards, about to get swallowed by the star, which would make the transits of the planet arrive earlier and earlier.
“So we had to work through all the other possible situations that could occur that would cause the same timing variations that we saw in the data,” says Dr Montet. “But our tests and simulations suggested that none of the other explanations are physically possible. It would take wild new physics that is very implausible, so we were able to rule those out and say the only option left is that it has to be another planet.
What can this teach us about planet formation?
The first exoplanets were discovered in the mid 90s. While scientists haven’t yet found an exoplanet that can support life like Earth, they have identified a number of Earth-sized rocky exoplanets, some of which are in the habitable zones of their stars, meaning they could potentially have water on their surface.
“There's a lot of questions about exoplanets that we haven't been able to answer yet,” says Dr Montet. “Whenever we find planets, they throw up new puzzles about how they form, and hot Jupiters are a great example of that. Hot Jupiters were the first exoplanets we discovered, but we don’t fully understand how they form or why they're there.”
One way scientists think hot Jupiters may form, called dynamical or warm excitation, is chaotic and can make the system unstable, ejecting other planets out of the planetary system. The second possibility is called cold migration, a smoother process where the planet gradually drifts inward. “If this smooth method is common, we would expect to find hot Jupiters with companion planets. But if they typically lack companions, it suggests the chaotic scattering process is more frequent,” says Dr Montet.
Current evidence points to a mix of both processes, but studying more hot Jupiters will help us determine which is more common.
Searching for more clues
Mr McKee and Dr Montet’s work has pointed to the unusual transit of TOI-2818b being the result of a companion planet. However, many questions remain unanswered. “There are lots of factors that we don’t know,” says Mr McKee. “There are a couple of different features of the planet that are compatible with our simulations.”
Further observations will help to narrow down exactly what kind of secondary planet is interfering. “The ESPRESSO instrument on the Chilean Very Large Telescope (VLT), run by the European Southern Observatory (ESO), will provide more data and help us to eliminate some of the possibilities when figuring out the features of the planet,” says Dr Montet. “ESPRESSO data already was really important in eliminating some other exotic solutions, like a brown dwarf orbiting the star and tugging on the hot Jupiter. The VLT is the best-placed instrument we have to measure exactly where this hidden planet is.
“Every time we find new planetary systems around other stars, we’re surprised that there are things that we did not envision, things that look nothing like our own solar system.
“Every time we think we really understand planet formation, we learn something new. And this is going to just keep happening over the next couple decades, as different missions come online and help us detect planets in new ways, using new techniques.”
Dr Montet highlights the importance of a collaborative approach to exoplanet hunting. “There are many more planets than people, but the more people who are able to collaborate, from well-established facilities, to citizen scientists, we can narrow down answers to some of the most important questions and understand more about the universe.”
A Planet Candidate Orbiting near the Hot Jupiter TOI-2818 b Inferred through Transit Timing
Article Publication Date
4-Mar-2025
Sharper image: U of A-built instrument reveals pictures of 'baby planets'
Unprecedented observations of newborn planets reveal rings of dust, which will likely give rise to moons, as well as startling changes in the planets' brightness, telltale signs of their turbulent youth.
Donuts of dust: An artist’s impression of the PDS 70 system with protoplanets, each surrounded by dust rings illuminated by starlight. The planets themselves (not to scale) have thin rings of plasma heated to around 14,000 degrees Fahrenheit, which glow at the red emission line of H-alpha light.
With a sun more than 4.5 billion years old, our solar system is considered "middle-aged," and the pictures of what it might have looked like in its infancy are lost to time. Taking advantage of a sophisticated adaptive optics instrument, a team of astronomers at the University of Arizona made observations that reveal unprecedented details of planets when they are very young.
The instrument, dubbed Magellan Adaptive Optics Xtreme, or MagAO-X, observed two young planets orbiting PDS 70, a very young 5 million-year-old star in the constellation Centaurus, 370 light-years from Earth.
Published in The Astronomical Journal, the observations show for the first time compact rings of dust surrounding the "baby planets," which will likely give rise to moons. The team also observed startling changes in planet brightness, telltale signs of the system's turbulent youth.
With a deformable mirror that changes its shape quickly, MagAO-X corrects for atmospheric distortion in a way that is reminiscent of how noise-cancelling headphones filter out noise.
"This is a really great breakthrough in technology," said Laird Close, a professor of astronomy at Steward Observatory, in the U of A College of Science, adding that the images surpass the resolution of space telescopes, including the 2.4-meter Hubble Space Telescope and the James Webb Space Telescope.
Paired with the 6.5-meter Magellan Telescope at Las Campanas Observatory in Chile, the instrument works as an "adaptive optics system," meaning it corrects for turbulence in the atmosphere that hampers astronomical observations. Effectively, the system eliminates the "twinkle" of stars, enabling the telescope to make images rivaling those from an optical space telescope.
"The mirror shape-shifts at a rate comparable to adjusting an eyeglasses prescription 2,000 times per second," Close said. "Because our technology removes disturbances from the atmosphere, it's a bit like taking a 6-1/2-meter telescope mirror and putting it in outer space by clicking a computer mouse button.
"This level of resolution revealed features around these planets in incredible detail," he added. "To give you an idea of the resolution, picture me standing in Phoenix, and you standing in Tucson. With MagAO-X, you'd be able to see whether I'm holding up one quarter-dollar coin or two from 125 miles away."
Astronomers believe that during its infancy, our solar system might have resembled a smaller version of the PSD 70 planetary system. The star is surrounded by a giant, pancake-shaped disk of gas and dust. Intriguingly, the disk is marked by a large dust-free gap, hinting at planets.
"Multiple massive planets act kind of like brooms or vacuum cleaners," Close said. "They basically scatter the dust away and clear the large gap that we observe in this great big disk of gas and dust that surrounds the star."
Infant planets, known as protoplanets, are very rare, and the PDS 70 planets b and c are the only such planets well known to astronomers out of 5,000 confirmed exoplanets. Developing sharper images of protoplanets and the dust around them is key to understanding how planets and their moons form, according to the research team.
Although the planets in PSD 70 already contain several times the mass of Jupiter, they are only about 5 million years old – which means that they are still growing. As the planets gain mass from their "birth cloud," "waterfalls" of hydrogen gas fall onto them, Close explained.
When that happens, the planets glow in what astronomers call H-alpha, a wavelength of light emitted by hydrogen gas when in a certain excited state from the shock heating of the gas hitting the planet’s surface.
"Targeting that special wavelength of light allows MagAO-X to effectively limit noise and distinguish between protoplanets and their surrounding features or imaging artifacts," Close explained.
"We can see, for the first time, rings of dust surrounding protoplanets made visible by the bright starlight reflecting off of them," added Jialin Li, a doctoral student in astronomy and co-author of the paper.
Over the next few million years, the dust likely will collapse to form moons around each of these young planets.
MagAO-X's sharp images revealed the first observation of young planets dramatically changing in brightness. The researchers saw one of the planets (PDS 70 b) fade to one-fifth its original brightness over just three years while the other (PDS 70 c) doubled in brightness, Close said, explaining that the rapid change in brightness at H-alpha could be due to changes in the amount of hydrogen gas that is flowing onto the planets.
"Essentially, one of the planets abruptly went on a diet while the other was feasting on hydrogen," he said.
Still, scientists are not yet sure what exactly causes such dramatic changes.
"Our team will continue to utilize MagAO-X to search for more protoplanets around other young stars," Close said. "While discovering these protoplanets is right at the edge of what is technically possible today, as technology improves we should discover more such systems in the near future."
"One of our main goals is to demonstrate just how well these observations can be done with telescopes on the ground.” said MagAO-X Principal Investigator Jared Males, an associate astronomer at Steward Observatory. "We can always build larger telescopes on the ground than in space, and this result shows how important it is to build the next generation of even larger telescopes and equip them with instruments like MagAO-X."
Funding for this work was provided by NASA Exoplanet Research Program. MagAO-X is supported by the National Science Foundation and the Heising-Simons Foundation.
This video animation shows an artist’s view of the PDS 70 system transition to real images of the two planets and their circumplanetary "dust donuts." The movie ends with the planets changing in brightness in H-alpha light over the last three years as they orbit PDS 70
Three Years of High-contrast Imaging of the PDS 70 b and c Exoplanets at Hα with MagAO-X: Evidence of Strong Protoplanet Hα Variability and Circumplanetary Dus
Researchers quantify the way rivers bend, opening up the possibility for identifying origins of channels on other planets
Satellite images show a sinuous ice channel in North East Land, Greenland; volcanic sinuous rille Rima Seuss on the Moon; and the meandering Juruá River in Brazil.
Credit: Compilation by Tim Goudge / Jackson School
Whether it’s rivers cutting through earth, lava melting through rock, or water slicing through ice, channels all twist and bend in a seemingly similar back-and-forth manner. But a new study led by scientists at The University of Texas at Austin has discovered that channels carved by rivers actually have curves distinct to those cut by lava or ice.
The exact mechanism that drives the shape of these bends is not certain, but the researchers cite several previous models that point to the relationship between the topography of the channel and the fluid’s flow within it.
In rivers, centrifugal force pushes water to go faster around the outer edges of the channel’s bends and more slowly along the inner edges. As a result, the water erodes the outer edge and deposits sediments along the inner edge, amplifying the river’s bends.
Volcanic and ice channels, on the other hand, are eroded thermally, through melting. And because they do not deposit sediments like rivers do, the only change that occurs in these channels is along the outer edge of a bend, making their curves comparatively smaller than those in rivers.
“This distinction sets up a great natural experiment for us to see if the shape, or size, of bends in rivers is distinct from those in volcanic or ice channels,” said Tim Goudge, a co-author on this paper and assistant professor at the Jackson School of Geosciences Department of Earth and Planetary Sciences.
These findings could have the potential to be used as a diagnostic tool for sinuous channels on other worlds, where the fluid’s origin may be unknown and scientists cannot be on the ground to take measurements and samples.
Juan Vazquez, who earned his undergraduate degree from the Jackson School in 2024, led the research while working with Goudge. He analyzed thousands of bends in rivers and ice channels on Earth and volcanic channels on the Moon. Vazquez said that what he thought was an analysis error at first ended up being an early indication that river bends have a more extreme size than other channels.
“It wasn’t until the parameters for the code we had set for the volcanic channels on the Moon kept failing for the rivers on Earth that we realized, ‘Oh, that’s not a fault of the code. It’s an intrinsically different amplitude,’” Vazquez said.
In their analysis, the researchers also found that thermally eroded volcanic and ice channels have a higher proportion of downstream accentuated bends compared to rivers.
On Earth, there are a number of ways to determine the origins of a channel, such as observing the fluid or noting geologic fingerprints the flow left behind. On planetary bodies like Titan, Saturn’s largest moon, it’s a trickier excercise. There, channels of liquid ethane and methane cut through water ice — but scientists can’t say from orbit whether these channels are meandering due to sediment transport and deposition like rivers are, or if they are eroded through melting or dissolution. There is a similar debate about the origin of channels on Mars, where there were flowing rivers and active volcanoes several billion years ago.
“There are these sinuous channels on the sides of Martian volcanos. Some people have interpreted them as volcanic channels, and some people have interpreted them as rivers that formed when maybe snowpack on the top of the volcano melted,” said Goudge. “We’re saying that because volcanic channel bends are so distinct, you can measure those channels to find out.”
However, Goudge cautioned against this research being used as a hard and fast rule. When looked at individually, channels of all kinds can vary dramatically, so Goudge said he would like for more channels to be cataloged and analyzed before this can be widely applied as a diagnostic tool.
“But I think it has the potential to be if we understand it more,” he said.
Mariel Nelson, a doctoral student at the Jackson School, also contributed to this research and is a co-author on the paper.
Caption
Volcanic sinuous rille Rima Seuss on the Moon.
Credit
Satellite image / Japan Aerospace Exploration Agency
annel in Greenland, centered at 79.52°N, 21.33°W.
Credit
Planet Labs PBC 2024
The meandering Juruá River in Brazil, centered at 5.75°S, 67.78°W.
Photos and outputs from instruments used for O-PTIR. Researchers can interpret the images on the left, made using different optical sensors, to produce graphs like those on the right, which show the presence of microbial life.
Within the next decade, space agencies plan to bring samples of rock from Mars to Earth for study. Of concern is the possibility these samples contain life, which could have unforeseen consequences. Therefore, researchers in this field strive to create methods to detect life. For the first time, researchers, including those from the University of Tokyo and NASA, successfully demonstrated a method to detect life in ancient rocks analogous to those found on Mars.
We’ve all seen the movies, in which “Scientists bring back something from space, with disastrous consequences,” or with some similar premise. The idea makes for a fun story, but the idea of microbial aliens contaminating the Earth is based on genuine concerns, and is also nothing new. Back in the days of the Apollo program, on their return, the lucky astronauts who stepped foot on lunar soil underwent decontamination procedures and even quarantines, just in case. More recently, all eyes are on Mars, as multiple sample return missions are being planned.
In order to ensure that samples from Mars cannot contaminate Earth life, the international Committee on Space Research (COSPAR) developed the sample safety assessment framework, essentially a set of protocols for those involved in obtaining, transporting and analyzing Mars rocks, to avoid contamination. A key component of this is our ability to detect the presence or absence of life in a sample. The issue of course being, we haven’t actually got any. To plug this gap, Associate Professor Yohey Suzuki from the Department of Earth and Planetary Science at the University of Tokyo, and his international team, looked at ancient microbe-rich Earth rocks analogous to the kind of Mars rocks we might expect to receive from the red planet in the coming years.
“We first tested conventional analytical instruments, but none could detect microbial cells in the 100-million-year-old basalt rock we use as the Martian analogue. So, we had to find an instrument sensitive enough to detect microbial cells, and ideally in a nondestructive way, given the rarity of the samples we may soon see,” said Suzuki. “We came up with optical photothermal infrared (O-PTIR) spectroscopy, which succeeded where other techniques either lacked precision or required too much destruction of the samples.”
O-PTIR works by shining infrared light onto prepared samples to analyze; in this case, the rocks had their outer layers removed and were cut into slices. While slightly destructive, it leaves plenty of material intact for other kinds of analyses, or even those we have not come up with. This essence of preservation for the future also took place with samples from the moon landings. A green laser then picks up signals from the sample where it was exposed to infrared light. With this, researchers can image details as small as half a micrometer, which is enough to discern when a structure is part of something living.
“We demonstrated our new method can detect microbes from 100-million-year-old basalt rock. But we need to extend the validity of the instrument to older basalt rock, around 2 billion years old, similar to those the Perseverance rover on Mars has already sampled,” said Suzuki. “I also need to test other rock types such as carbonates, which are common on Mars and here on Earth often contain life as well. It’s an exciting time to work in this field. It might only be a matter of years before we can finally answer one of the greatest questions ever asked.”
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Journal article:
Yohey Suzuki, Mariko Koduka, Frank E. Brenker, Tim Brooks, Mihaela Glamoclija, Heather V. Graham, Thomas L. Kieft, Francis M. McCubbin, Mark A. Sephton and Mark A. van Zuilen, “Submicron-scale detection of microbes and smectite from the interior of a Mars-analogue basalt sample by opticalphotothermal infrared spectroscopy”, International Journal of Astrobiology, http://doi.org/10.1017/S1473550425000011
Funding:Y. S. was supported by the Astrobiology Center Program of National Institutes of Natural Sciences (NINS) (AB0502). M. A. S. was supported by UK Space Agency grants ST/V002732/1 and ST/V006134/1.
Research contact: Associate Professor Yohey Suzuki Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan yohey-suzuki@eps.s.u-tokyo.ac.jp
Press contact: Mr. Rohan Mehra Public Relations Group, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan press-releases.adm@gs.mail.u-tokyo.ac.jp
About The University of Tokyo:
The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on X (formerly Twitter) at @UTokyo_News_en.
We don’t just have sex to reproduce - new research suggests that using sex to manage social tension could be a trait that existed in the common ancestor of humans and apes six million years ago.
Humans share this behavioural strategy with our closest living ape relatives – bonobos and chimpanzees.
Now researchers, led by Durham University, UK, have undertaken what is thought to be one of the first direct comparisons of sexual behaviour amongst bonobos and chimpanzees during periods of social stress.
Their findings, published in the journal Royal Society Open Science, could give us new insights into humans’ own behavioural origins.
The least studied of the apes, the bonobos, are known to regularly use sex to resolve disputes and repair social bonds. By comparison, the role of sex in chimpanzee society has been less well understood.
The team observed sexual contact within sanctuary-living bonobos and chimpanzees during two stressful periods; following naturally-occurring social conflicts and prior to feeding.
By comparing both apes living in similar environments, the researchers could understand if using sex to ease social tension is a common behavioural trait between the two sister species.
The findings showed that both bonobos and chimpanzees used sex in similar ways to ease tension and reaffirm social bonds prior to feeding, when competition and power differences can provoke disagreement.
However, bonobos also often had sex more after fights to repair social relations, whilst in these circumstances, chimpanzees were more likely to use other social behaviours, with clearer signals, to provide comfort and restore relations.
The researchers say the fact that both bonobos and chimpanzees have sex to ease social tension supports the idea that using sex for social purposes was already present in the last common ancestor they share with humans, dating back over six million years. Human sex is not only for reproduction, and the same seems to be the case for our relatives too, as well as other animals.
While age did not influence the use of sex to reconcile after fights amongst either bonobos or chimpanzees, the researchers saw that prior to feeding it was the older apes in both species who were more likely to initiate sex, indicating that this could be a learned behaviour, passed down over time.
Lead author Jake Brooker, a postdoctoral researcher in the Department of Psychology, Durham University, said: “This is a first direct comparison of sexual behaviour in bonobos and chimpanzees, two of our closest cousins.
“Whilst bonobos, who are famously hypersexual, were more likely to engage in so-called ‘make up sex’ after periods of conflict, we found that chimpanzees, who some view as our more aggressive cousin, also use sex to ease tensions in many circumstances.
“Chimpanzees are known to have a wider repertoire of reassurance behaviours, including body kissing, but sex still constituted a sizeable portion of how they reconciled with each other and their stress-management behaviour.
“The fact that both species use sex in this way provides a fascinating window back in time, further evidencing that for humans, bonobos and chimpanzees, our use of sex for social reasons is something we have inherited from our common ancestor.”
The study took place at two African great ape sanctuaries: Lola ya Bonobo Sanctuary in the Democratic Republic of Congo, and Chimfunshi Wildlife Orphanage Trust in Zambia.
In total over 1,400 hours of observations were taken involving 53 bonobos and 75 chimpanzees, across seven months in 2019.
Amongst the observations made by the researchers it was noted that female bonobos and male chimpanzees were more likely to initiate sex prior to feeding, but in both species, sex occurred in both hetero and homosexual combinations.
Research senior author Professor Zanna Clay, Department of Psychology, Durham University, said: “Bonobos are famous for using sex to navigate social challenges but much less is known about the role of sex in chimpanzee society.
“By directly comparing the two species in similar environments during two key situations, we can test the social role of sex in our closest ape relatives, and gain deeper understanding about how it may have evolved in our own species too.
“Against the assumptions of pacifist sex-mad bonobos and aggressive chimpanzees, we found that both species used sex in similar ways during tense situations, including same-sex pairings. This study highlights that beyond reproduction, sex plays an important role in their societies, and most likely for our early ancestors too.
“An exciting next step would be to test the functions of sex further, in different contexts, and to see how much overlap we see between chimpanzee and bonobo sexuality in the wild.”
The research was funded by the Templeton World Charity Foundation: Diverse Intelligences Framework and included researchers from Harvard University and Emory University in the USA, Utrecht University in The Netherlands and Max Plank Institute for Evolutionary Anthropology in Germany.
The research was conducted with full approval from the Chimfunshi Research Advisory Board (CRAB), the Senior Veterinary Advisory Team of Lola ya Bonobo Sanctuary, and the Animal Welfare Ethics and Research Board (AWERB) of Durham University. Data collection consisted of naturalistic observations and experimental procedures that adhered to the legal requirements of the Democratic Republic of the Congo and Zambia, as well as the International Primatological Society’s Principles for the Ethical Treatment of Nonhuman Primates.
ENDS
Male chimpanzee embracing and body kissing his close male ally following social tension.
Credit
Jake Brooker/Chimfunshi Wildlife Orphanage Trust
Adolescent male bonobo at Lola ya Bonobo Sanctuary, DR Congo.
Two juvenile bonobos embrace at Lola ya Bonobo Sanctuary, DR Congo.
A group of bonobos communicate to another group at Lola ya Bonobo Sanctuary, DR Congo.
A group of bonobos at Lola ya Bonobo Sanctuary, DR Congo.
Two male bonobos groom one another at Lola ya Bonobo Sanctuary, DR Congo.
