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, December 18, 2024
SPACE / COSMOS
First ever binary star found near our galaxy’s supermassive black hole
ESO
image:
This image indicates the location of the newly discovered binary star D9, which is orbiting Sagittarius A*, the supermassive black hole at the centre of our galaxy. It is the first star pair ever found near a supermassive black hole. The cut-out shows the binary system as detected by the SINFONI spectrograph on ESO’s Very Large Telescope. While the two stars cannot be discerned separately in this image, the binary nature of D9 was revealed by the spectra captured by SINFONI over several years. These spectra showed that the light emitted by hydrogen gas around D9 oscillates periodically towards red and blue wavelengths as the two stars orbit each other.
An international team of researchers has detected a binary star orbiting close to Sagittarius A*, the supermassive black hole at the centre of our galaxy. It is the first time a stellar pair has been found in the vicinity of a supermassive black hole. The discovery, based on data collected by the European Southern Observatory’s Very Large Telescope (ESO’s VLT), helps us understand how stars survive in environments with extreme gravity, and could pave the way for the detection of planets close to Sagittarius A*.
“Black holes are not as destructive as we thought,” says Florian Peißker, a researcher at the University of Cologne, Germany, and lead author of the study published today in Nature Communications. Binary stars, pairs of stars orbiting each other, are very common in the Universe, but they had never before been found near a supermassive black hole, where the intense gravity can make stellar systems unstable.
This new discovery shows that some binaries can briefly thrive, even under destructive conditions. D9, as the newly discovered binary star is called, was detected just in time: it is estimated to be only 2.7 million years old, and the strong gravitational force of the nearby black hole will probably cause it to merge into a single star within just one million years, a very narrow timespan for such a young system.
“This provides only a brief window on cosmic timescales to observe such a binary system — and we succeeded!” explains co-author Emma Bordier, a researcher also at the University of Cologne and a former student at ESO.
For many years, scientists also thought that the extreme environment near a supermassive black hole prevented new stars from forming there. Several young stars found in close proximity to Sagittarius A* have disproved this assumption. The discovery of the young binary star now shows that even stellar pairs have the potential to form in these harsh conditions. “The D9 system shows clear signs of the presence of gas and dust around the stars, which suggests that it could be a very young stellar system that must have formed in the vicinity of the supermassive black hole,” explains co-author Michal Zajaček, a researcher at Masaryk University, Czechia, and the University of Cologne.
The newly discovered binary was found in a dense cluster of stars and other objects orbiting Sagittarius A*, called the S cluster. Most enigmatic in this cluster are the G objects, which behave like stars but look like clouds of gas and dust.
It was during their observations of these mysterious objects that the team found a surprising pattern in D9. The data obtained with the VLT’s ERIS instrument, combined with archival data from the SINFONI instrument, revealed recurring variations in the velocity of the star, indicating D9 was actually two stars orbiting each other. “I thought that my analysis was wrong,” Peißker says, “but the spectroscopic pattern covered about 15 years, and it was clear this detection is indeed the first binary observed in the S cluster.”
The results shed new light on what the mysterious G objects could be. The team proposes that they might actually be a combination of binary stars that have not yet merged and the leftover material from already merged stars.
The precise nature of many of the objects orbiting Sagittarius A*, as well as how they could have formed so close to the supermassive black hole, remain a mystery. But soon, the GRAVITY+ upgrade to the VLT Interferometer and the METIS instrument on ESO’s Extremely Large Telescope (ELT), under construction in Chile, could change this. Both facilities will allow the team to carry out even more detailed observations of the Galactic centre, revealing the nature of known objects and undoubtedly uncovering more binary stars and young systems. “Our discovery lets us speculate about the presence of planets, since these are often formed around young stars. It seems plausible that the detection of planets in the Galactic centre is just a matter of time,” concludes Peißker.
More information
This research was presented in the paper “A binary system in the S cluster close to the supermassive black hole Sagittarius A*” published today in Nature Communications (doi: 10.1038/s41467-024-54748-3).
The team is composed of F. Peißker (Institute of Physics I, University of Cologne, Germany [University of Cologne]), M. Zajaček (Department of Theoretical Physics and Astrophysics, Masaryk University, Brno, Czechia; University of Cologne), L. Labadie (University of Cologne), E. Bordier (University of Cologne), A. Eckart (University of Cologne; Max Planck Institute for Radio Astronomy, Bonn, Germany), M. Melamed (University of Cologne), and V. Karas (Astronomical Institute, Czech Academy of Sciences, Prague, Czechia).
The European Southern Observatory (ESO) enables scientists worldwide to discover the secrets of the Universe for the benefit of all. We design, build and operate world-class observatories on the ground — which astronomers use to tackle exciting questions and spread the fascination of astronomy — and promote international collaboration for astronomy. Established as an intergovernmental organisation in 1962, today ESO is supported by 16 Member States (Austria, Belgium, Czechia, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom), along with the host state of Chile and with Australia as a Strategic Partner. ESO’s headquarters and its visitor centre and planetarium, the ESO Supernova, are located close to Munich in Germany, while the Chilean Atacama Desert, a marvellous place with unique conditions to observe the sky, hosts our telescopes. ESO operates three observing sites: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its Very Large Telescope Interferometer, as well as survey telescopes such as VISTA. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. Together with international partners, ESO operates ALMA on Chajnantor, a facility that observes the skies in the millimetre and submillimetre range. At Cerro Armazones, near Paranal, we are building “the world’s biggest eye on the sky” — ESO’s Extremely Large Telescope. From our offices in Santiago, Chile we support our operations in the country and engage with Chilean partners and society.
Young exoplanet’s atmosphere unexpectedly differs from its birthplace
New study shows planet formation might be more complicated than previously thought
Northwestern University
image:
The natal disk of PDS 70 with new planet PDS 70b (bright spot on the right). By studying this system, researchers uncovered a mismatched composition of gases in the planet’s atmosphere compared to gases within the disk.
Just as some children physically resemble their parents, many scientists have long thought that developing planets should resemble the swirling disk of gas and dust that births them.
But, in a new study, a Northwestern University-led team of astrophysicists discovered the resemblance might be looser than previously thought. By studying a still-forming exoplanet and its surrounding natal disk, the researchers uncovered a mismatched composition of gases in the planet’s atmosphere compared to gases within the disk.
The surprising finding potentially confirms long-held skepticism that scientists’ current model of planet formation is too simplified.
The study will be published on Wednesday (Dec. 18) in the Astrophysical Journal Letters. It marks the first time physicists have compared information from an exoplanet, its natal disk and host star.
“For observational astrophysicists, one widely accepted picture of planet formation was likely too simplified,” said Northwestern’s Chih-Chun “Dino” Hsu, who led the study. “According to that simplified picture, the ratio of carbon and oxygen gases in a planet’s atmosphere should match the ratio of carbon and oxygen gases in its natal disk — assuming the planet accretes materials through gases in its disk. Instead, we found a planet with a carbon and oxygen ratio that is much lower compared to its disk. Now, we can confirm suspicions that the picture of planet formation was too simplified.”
All planets are born from a natal disk, a rotating disk of gas and dust that surrounds a new star. Over millions of years, gravity pulls gas and dust together to form clumps, which eventually grow into planets. Until recently, it was impossible to obtain a direct view of a natal disk in order to track a planet’s birth. Most observable exoplanets are too old, so their natal disks have already disappeared.
The exception, however, is PDS 70, a natal disk that envelopes two fledgling gas-giant exoplanets — similar to Jupiter — called PDS 70b and PDS 70c. Located just 366 million lightyears from Earth within the constellation Centaurus, the planets are, at most, a youthful 5 million years old.
“This is a system where we see both planets still forming as well as the materials from which they formed,” Wang said. “Previous studies have analyzed this disk of gas to understand its composition. For the first time, we were able to measure the composition of the still-forming planet itself and see how similar the materials are in the planet compared to the materials in the disk.”
Examining planetary fingerprints
To measure the materials, Hsu, Wang and their team examined the light emitted from PDS 70b. This light, or spectra, is like a fingerprint, revealing an object’s composition, motion, temperature and other characteristics. Each molecule or element produces its own spectrum. So, by studying these spectra, researchers can pinpoint the specific molecules or elements within an object.
In previous work, Wang co-developed new photonics technologies that enable astronomers to capture the spectrum of targeted faint objects near much brighter stars. The researchers used this technique to zero in on the faint features of the young planetary system.
“These new tools make it possible to take a really detailed spectra of faint objects next to really bright objects,” Wang said. “Because the challenge here is there’s a really faint planet next to a really bright star. It’s hard to isolate the light of the planet in order to analyze its atmosphere.”
With the spectra, the researchers obtained information about carbon monoxide and water from PDS 70b. From that, they calculated the inferred ratio of carbon and oxygen within the planet’s atmosphere. Then, they compared that ratio to previously reported measurements of gases in the disk.
“We initially expected the carbon-to-oxygen ratio in the planet might be similar to the disk,” Hsu said. “But, instead, we found the carbon, relative to oxygen, in the planet was much lower than the ratio in the disk. That was a bit surprising, and it shows that our widely accepted picture of planet formation was too simplified.”
Solid components might make the difference
To explain this mismatch, Hsu and Wang think two different scenarios might be at play. One explanation is the planet might have formed before its disk became enriched in carbon. Another explanation is the planet might have grown mostly by absorbing large amounts of solid materials in addition to gases. While the spectra show only gases, some of the carbon and oxygen initially could be accreted from solid — trapped in ice and dust.
“If the planet preferentially absorbed ice and dust, then that ice and dust would have evaporated before going into the planet,” Wang said. “So, it might be telling us that we can’t just compare gas versus gas. The solid components might be making a big difference in the carbon to oxygen ratio.”
For this study, the team only studied PDS 70b. Next, they plan to observe the spectra from the other planet in the PDS 70 system.
“By studying these two planets together, we can understand the system’s formation history even better,” Hsu said. “But, also, this is just one system. Ideally, we need to identify more of them to better understand how planets form.”
The study, “PDS 70b shows stellar-like carbon-to-oxygen ratio,” was supported by the Heising-Simons Foundation, the Simons Foundation and the National Science Foundation.
Journal
The Astrophysical Journal Letters
Method of Research
Observational study
Article Title
PDS 70b shows stellar-like carbon-to-oxygen ratio
Article Publication Date
18-Dec-2024
Brain cells remain healthy after a month on the International Space Station, but mature faster than brain cells on Earth
Scripps Research scientists reveal microgravity’s effects on brain cells
Scripps Research Institute
image:
Brain organoids were healthy and continued to grow after spending a month on the International Space Station.
LA JOLLA, CA—Microgravity is known to alter the muscles, bones, the immune system and cognition, but little is known about its specific impact on the brain. To discover how brain cells respond to microgravity, Scripps Research scientists, in collaboration with the New York Stem Cell Foundation, sent tiny clumps of stem-cell derived brain cells called “organoids” to the International Space Station (ISS).
Surprisingly, the organoids were still healthy when they returned from orbit a month later, but the cells had matured faster compared to identical organoids grown on Earth—they were closer to becoming adult neurons and were beginning to show signs of specialization. The results, which could shed light on potential neurological effects of space travel, were published on October 23, 2024, in Stem Cells Translational Medicine.
“The fact that these cells survived in space was a big surprise,” says co-senior author Jeanne Loring, PhD, professor emeritus in the Department of Molecular Medicine and founding director of the Center for Regenerative Medicine at Scripps Research. “This lays the groundwork for future experiments in space, in which we can include other parts of the brain that are affected by neurodegenerative disease.”
On Earth, the team used stem cells to create organoids consisting of either cortical or dopaminergic neurons, which are the neuronal populations impacted in multiple sclerosis and Parkinson’s disease—diseases that Loring has studied for decades. Some organoids also included microglia, a type of immune cell that is resident within the brain, to examine the impact of microgravity on inflammation.
Organoids are usually grown in a nutrient-rich liquid medium that must be changed regularly to ensure that the cells have adequate nutrition, and to remove waste products. To avoid the need for lab work on the ISS, the team pioneered a method for growing smaller-than-usual organoids in cryovials—small, airtight vials that were originally designed for deep freezing.
The organoids were prepared in labs at the Kennedy Space Station and traveled to the ISS in a miniature incubator. After a month in orbit, they returned to Earth, where the team showed that they were healthy and intact.
To examine how the space environment impacts cellular functions, the team compared the cells’ RNA expression patterns—a measure of gene activity—to identical “ground control” organoids that had remained on Earth. Surprisingly, they found that the organoids grown in microgravity had higher levels of genes associated with maturity and lower levels of genes associated with proliferation compared to the ground controls, meaning that the cells exposed to microgravity developed faster and replicated less than those on Earth.
“We discovered that in both types of organoids, the gene expression profile was characteristic of an older stage of development than the ones that were on ground,” says Loring. “In microgravity, they developed faster, but it’s really important to know these were not adult neurons, so this doesn’t tell us anything about aging.”
The team also noted that, contrary to their hypothesis, there was less inflammation and lower expression of stress-related genes in organoids grown in microgravity, but more research is needed to determine why.
Loring speculates that microgravity conditions may more closely mirror the conditions experienced by cells within the brain compared to organoids grown under conventional lab conditions and in the presence of gravity.
“The characteristics of microgravity are probably also at work in people's brains, because there's no convection in microgravity—in other words, things don't move,” says Loring. “I think that in space, these organoids are more like the brain because they're not getting flushed with a whole bunch of culture medium or oxygen. They're very independent; they form something like a brainlet, a microcosm of the brain.”
The paper describes the team’s first space mission, but since then, they have sent four more missions to the ISS. With each one, they’ve replicated the conditions from the first mission and added additional experiments.
“The next thing we plan to do is to study the part of the brain that's most affected by Alzheimer's disease,” says Loring. “We also want to know whether there are differences in the way neurons connect with each other in space. With these kinds of studies, you can't rely on earlier work to predict what the result would be because there is no earlier work. We're on the ground floor, so to speak; in the sky, but on the ground floor.”
This work was supported by funding from the National Stem Cell Foundation.
In addition to Loring, authors of the study, “Effects of microgravity on human iPSC-derived neural organoids on the International Space Station” are Jason Stein of Scripps Research; Davide Marotta, Laraib Ijaz, Lilianne Barbar, Madhura Nijsure, Nicolette Pirjanian, Ilya Kruglikov, Scott A. Noggle, and Valentina Fossati of The New York Stem Cell Foundation Research Institute; Twyman Clements and Jana Stoudemire of Space Tango; and Paula Grisanti of the National Stem Cell Foundation.
About Scripps Research
Scripps Research is an independent, nonprofit biomedical institute ranked one of the most influential in the world for its impact on innovation by Nature Index. We are advancing human health through profound discoveries that address pressing medical concerns around the globe. Our drug discovery and development division, Calibr-Skaggs, works hand-in-hand with scientists across disciplines to bring new medicines to patients as quickly and efficiently as possible, while teams at Scripps Research Translational Institute harness genomics, digital medicine and cutting-edge informatics to understand individual health and render more effective healthcare. Scripps Research also trains the next generation of leading scientists at our Skaggs Graduate School, consistently named among the top 10 US programs for chemistry and biological sciences. Learn more at www.scripps.edu.
Journal
Stem Cells Translational Medicine
Article Title
Effects of microgravity on human iPSC-derived neural organoids on the International Space Station
Astrophysics: Mystery of the ‘missing’ binary stars solved
University of Cologne
An international team of researchers led by PD Dr Florian Peißker has found the first binary star in the immediate vicinity of the supermassive black hole Sgr A* (Sagittarius A star) at the centre of our galaxy. Although it is known that most stars in the universe do not form alone, so far there are only five confirmed binary stars at a greater distance from the black hole. None of the systems are so close. The researchers assume that the binary star system they found, named D9, will merge into a single star in the near future. The discovery was published in Nature Communications under the title ‘A binary system in the S cluster close to the supermassive black hole Sagittarius A*’. The work contributes to a better understanding of the centre of our galaxy and the conditions around the supermassive black hole.
For approximately thirty years it has been possible to observe individual stars in the vicinity of the black hole using infrared telescopy. So far, many of the observations have raised more questions. The central region around the supermassive black hole Sgr A* contains millions of stars and is divided into various sub-regions. A particularly interesting region of this so-called ‘inner parsec’ is the S star cluster, which contains Sgr A*. Due to its high density of stars, there should in theory be many binary stars. However, the five known binary stars are actually located in other, more distant regions, while none have yet been detected in this star cluster.
Researchers attributed this to gravitational forces: The stars in the S star cluster move in stable orbits around the black hole, similar to the Earth orbiting the Sun. However, the conditions there are much more extreme, as Sgr A* is four million times heavier than our sun. The stars therefore can reach speeds of several thousand kilometres per second, making it an unfavourable environment for the formation of binary star systems.
The researchers discovered D9 by taking a different approach to observing certain dust sources in the S star cluster. Normally, several individual observations over the course of a year are superimposed and added together to amplify the signal of the objects. “Nobody has looked closely at individual observations of the dust sources each night,” said Florian Peißker from the University of Cologne’s Institute of Astrophysics. “That was the crux of our study: investigating and analysing every single night. The data from the recordings is noisier, but still good enough. This is how we identified the binary star.”
The discovery of D9 now opens up the possibility for researchers to investigate the processes of star formation in more detail, as the system is very likely to merge in the coming decades to millennia and thus form a new, slightly heavier star. This would solve another mystery. Because the stars in the S star cluster close to the supermassive black hole are younger than any star cluster theory has predicted. The presence of the binary star system could therefore provide new clues as to how the stars form around the central black hole. The researchers assume that some of the young stars formed from binary star systems that had previously migrated from the area of the ‘inner parsec’ to the supermassive black hole.
Co-author Dr Michael Zajaček from Masaryk University in Brno, Czech Republic, said: “Until now, it was a mystery how such young stars could form so close to Sgr A*, which in principle should prevent any gravitational collapse that is necessary for star formation. The discovery of this binary star system will significantly expand our knowledge regarding star formation.” Dr Emma Bordier, co-author and postdoc in the Collaborative Research Centre 1601 ‘Habitats of Massive Stars across Cosmic Time’ at the University of Cologne, added: “Different generations of Very Large Telescope instruments were used for these observations. The new findings clearly demonstrate how the combination of archival data and recent observations can complement each other to enable innovative studies and lead to exciting discoveries.”
Journal
Nature Communications
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
A binary system in the S cluster close to the supermassive black hole Sagittarius A*
Article Publication Date
17-Dec-2024
SwRI awarded $26 million to develop NOAA magnetometers
SW-MAG data will help NOAA predict, mitigate the effects of space weather
Southwest Research Institute
image:
Southwest Research Institute is developing magnetometers for NOAA’s Space Weather Next (SW Next) program for two missions to be launched in 2029 and 2032. The magnetometers will be based on the SWFO-MAG pictured here to measure the interplanetary magnetic field carried by the solar wind.
SAN ANTONIO — December 17, 2024 —NASA and the National Oceanic and Atmospheric Administration (NOAA) recently awarded Southwest Research Institute a $26 million contract to develop magnetometers for NOAA’s Space Weather Next (SW Next) program for two missions to be launched in 2029 and 2032. The magnetometers will measure the interplanetary magnetic field carried by the solar wind.
“The instruments provide critical data to NOAA’s Space Weather Prediction Center which issues forecasts, warnings and alerts that help mitigate space weather impacts,” said Dr. Roy Torbert, a program director in SwRI’s Earth, Oceans, and Space office at the University of New Hampshire (UNH) in Durham, N.H., and principal investigator of the magnetometer. “Space weather refers to the variable conditions on the Sun and in space that can influence the performance of technology we use on Earth, such as electrical power grids, and disrupt satellite-based communication and navigation systems.”
The magnetometers will be deployed on satellites that will orbit the Sun at approximately 1.5 million kilometers from the Earth at a point known as Lagrange 1, or L1. Gravitational forces from the Sun and the Earth hold objects at L1 in a stable position and offer an uninterrupted view of the Sun. The instrument will make local measurements of the magnetic field conveyed by the solar wind as it blows towards the Earth.
“The instrument, known as SW-MAG, provides key data about the solar wind as it approaches Earth,” Torbert said. “The data will be available to the science community but are targeted to the Space Weather Prediction Center.”
SwRI will work with UNH to design, develop, fabricate, integrate, calibrate and evaluate the magnetometer instrument. The team will also support launch and on-orbit check-out of the instrument, supply and maintain the instrument’s ground support equipment, and support NOAA’s mission operations center as needed. SW-MAG includes two three-axis magnetometers and associated electronics to measure the vector interplanetary magnetic field.
“The solar wind magnetic field controls the processes that transfer energy and particles into the Earth’s magnetosphere and often initiates geomagnetic storms,” Torbert said. “These disturbances can create spectacular auroras but can also shut down electrical power grids and disrupt satellite-based communication and navigation systems.”
NASA is planning to launch the SW-NEXT as a follow-up to the SWFO-L1 mission, which also will have an SwRI-developed magnetometer in its payload, in 2025 as a rideshare with the Interstellar Mapping and Acceleration Probe (IMAP) vehicle. SwRI also plays a role in that mission, managing the payload and payload systems engineering for IMAP, which will sample, analyze and map particles streaming to Earth from the edge of interstellar space.
NASA and NOAA oversee the development, launch, testing, and operation of all the satellites in the Lagrange 1 Series project. NOAA is the program owner providing the requirements and funding along with managing the program, operations, data products, and dissemination to users. NASA and its collaborators will develop and build the instruments and spacecraft and provide launch services on behalf of NOAA. SwRI will work with NASA’s Goddard Space Flight Center and Kennedy Space Center to develop the magnetometers.
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