Category: 7. Science

Georgia State University’s Center for High Angular Resolution Astronomy (CHARA), a six-telescope interferometer, excels at studying stars. It’s been observing them for 20 years and has contributed to 276 published papers. The University is celebrating its achievements so far, and underscoring how Georgia State evolved from an institution not known for research to one that’s now considered a large research university.

GSU scientist Hal McAlister was the lead author for one of the first papers published based on CHARA data, and is now a Regents’ Professor Emeritus of Astronomy at GSU. That paper was focused on the star Regulus, part of the Leo constellation and one of the brightest stars in the sky. “These first results from the CHARA Array provide the first interferometric measurement of gravity darkening in a rapidly rotating star and represent the first detection of gravity darkening in a star that is not a member of an eclipsing binary system,” that paper state.

Since then, CHARA has contributed to astrophysics in many ways. It’s measured the sizes of stars across a wide range of masses and evolutionary stages, and when combined with data from Gaia and Hipparcos, have let scientists study stellar evolution models more deeply and thoroughly. It’s revealed the oblate shapes of rapidly-rotating stars and imaged features on their surface. It’s resolved circumstellar disks around Be stars, made of material ejected from the stars themselves.

“It’s been a joy to witness CHARA grow to even greater heights thanks to the dedication of so many over the years,” McAlister said.

Theo ten Brummelaar was the lead author of the second paper published based on CHARA. It explained how the array worked and outlined how GSU planned to upgrade the array in the future. ten Brummelaar was director of the CHARA Array until his retirement in 2022.

“At the time, Georgia State University wasn’t the large research university it is now, and very few people thought we’d get the funding, let alone be successful at building the CHARA Array,” ten Brummelaar said of the early days of the project. “We were a very small team of people with little history of designing and building large instruments like this. Nevertheless, we had a great deal of support, both financial and moral, from the university, and now CHARA and GSU are leaders in the field of ground-based optical interferometry and the astrophysics it enables.”

In our current age of exoplanet discovery, the nature of the stars they orbit is critically important to understanding the planets themselves. “Without understanding stars, we’ll never understand planets,” ten Brummelaar said in an interview.

This figure shows 693 stars. It’s an HR diagram of stars, many of which host exoplanets, that was created using interferometry data from CHARA, as well as data from other sources. It’s a great example of the contribution CHARA has made in its first 20 years. Image Credit: Ashley Elliott 2024.

“We knew in 2005 that the array would open a new window on the universe,” said current CHARA Director Douglas Gies. “But it is astonishing how much the array has revealed to us about the stars and their lives.”

CHARA also excels at measuring rapidly-rotating stars. They push the boundaries of stellar physics, and anything that pushes Nature’s boundaries can tell scientists a lot. Rapid rotators are known for gravity darkening.

These are some of the rapidly-rotating stars studied by CHARA. The rapid rotation deforms the stars into oblate shapes. That means the equators are further from the cores, and are cooler as a result. This is called gravity darkening, since the equators have less gravity than the poles. Image Credit: CHARA Array/John Monnier

CHARA has also contributed to our understanding of Nova explosions. These occur in tight binaries where one star is a white dwarf. The white dwarf draws hydrogen away from its companion, where it builds up as a layer on the outside of the white dwarf. Eventually, the hydrogen explodes as a Nova, which is bright at first then slowly fades over months. CHARA has imaged the expanding fireballs that form immediately after the explosion. CHARA observations produced the first images of a Nova during the early fireball stage and revealed how the structure of the ejected material evolves as the gas expands and cools.

This research figure shows how the CHARA array was able to measure the expansion of a Nova fireball from Nova Delphinus 2013 (V339 Del). CHARA was able to show that there’s more complexity in these events than thought. By measuring the expansion rate accurately, CHARA showed that a bipolar structure forms as early as the second day and indicates that the fireball is clumpy. Image Credit: Schaefer et al. 2014, Nature, 515, 243

CHARA observing time is in high demand, and in 2024, the National Science Foundation granted CHARA $3.5 million to allow more researchers to access the array.

“The National Science Foundation award is the key to open the array to the best ideas about new avenues for research,” said Chara Director Gies. “There will be remarkable new results coming soon about stars, planets and distant active galaxies.”

CHARA has seen several upgrades in recent years. New instruments and cameras have increased its power considerably. In 2024, a seventh mobile telescope was added to the array. This is a key upgrade, since the other six are in fixed positions, and will help the array image the surfaces of even larger stars. It will increase the array’s baseline from 330 meters to 550 meters. The seventh telescope is also a test case for further future development of the array.

“CHARA runs the best optical and infrared interferometer in the world and delivers the highest resolution observations possible at these wavelengths,” said Nigel Sharp, a program director in NSF’s Division of Astronomical Sciences. “It is exciting to see that such observations can be delivered routinely and that CHARA’s sought-after capabilities are now available to non-experts in the research community.”

July 23 (UPI) — Planned moon and Mars missions require timely communications and navigation systems, which is prompting NASA officials to request ideas via proposals from U.S. firms.

NASA on July 7 issued a request for proposals for a “high-bandwidth, high-reliability communications infrastructure” between the surfaces of the moon and Mars and respective Earth-based communications centers.

“These partnerships foster important advancements in communications and navigation,” said Greg Heckler, deputy program manager for NASA’s Space Communications and Navigation program.

“It allows our astronauts, our rovers, our spacecraft – all NASA missions – to expand humanity’s exploration of the moon, Mars and beyond,” Heckler said.

The communications and navigation infrastructure would support a marketplace for ongoing science, exploration and economic development in space by NASA and private aerospace firms.

More than 100 NASA and private space missions rely on the NASA SCAN program’s Near Space and Deep Space networks, according to the space agency.

Such missions support astronauts on the International Space Station, future Artemis moon missions, Earth weather monitoring, lunar exploration and researching the solar system and beyond.

NASA is accepting submissions through 5 p.m. EDT on Aug. 13.

The space agency in December awarded contracts for the Near Space Network to Intuit Machines of Houston; Norway’s Kongsberg Satellite Services; SSC Space U.S. Inc. of Horsham, Pa.; and Viasat Inc. of Duluth, Ga.

Such initiatives are intended to enable manned missions to Mars and support a moon-based habitat and lunar surface cargo lander.

NASA also approved contracts with nine companies that paid each between $200,000 and $300,000 to conduct tests in support of future Mars missions.

The tests involve commercial and exploration missions that are part of NASA’s Mars Exploration Program, which is slated to send missions to Mars over the next two decades.

First published in 1865 as a caterpillar, nearly fifty years before the discovery of Canada’s Burgess Shale, Palaeocampa anthrax shuffled between classifications — worm, millipede, and marine polychaete — until 130 years later, when University of Michigan paleontologist Richard Knecht and his colleagues realized its true identity: Palaeocampa anthrax most likely inhabited a freshwater environment, contesting the view that Paleozoic lobopodians were exclusively marine.

Lobopodians are extinct, soft-bodied creatures that bridge the evolutionary gap between a primitive worm-like ancestor and modern arthropods like insects and crustaceans.

Known mostly from Cambrian marine deposits such as the Burgess Shale, they include iconic fossils like Hallucigenia and Aysheaia pedunculata discovered in 1911, and were thought to be exclusively marine — until now.

“Lobopodians were likely a common sight on Paleozoic sea beds, but apart from microscopic tardigrades and terrestrial velvet worms, we thought they were confined to the ocean,” Dr. Knecht said.

In new research, Dr. Knecht and co-authors analyzed 43 specimens of Palaeocampa anthrax from two Carboniferous Lagerstätten — Mazon Creek in the United States and Montceau-les-Mines in France — using advanced imaging, including backscatter scanning electron microscopy (SEM) and energy-dispersive spectroscopy.

They revealed exquisite anatomical features — most notably, nearly 1,000 bristle-like spines covering the body.

Using Fourier-transform infrared spectroscopy (FTIR), they also detectedchemical residues at the spine tips — suggesting the spines secreted toxins to deter predators in its swampy habitat.

“What amazed me is that fragments of biomacromolecules could be exceptionally preserved or altered to geomacromolecules in fossils,” said Columbia University paleontologist Nanfang Yu.

“I’m thrilled this technique possessed the sensitivity and specificity to differentiate fossilized remains from the rocky substrate.”

Palaeocampa anthrax from Mazon Creek Lagerstätte. Image credit: Knecht et al., doi: 10.1038/s42003-025-08483-0.

According to the team, Palaeocampa anthrax’s closest relative is Hadranax, a Cambrian lobopodian from Greenland, nearly 200 million years older.

Both had ten pairs of legs, no claws and were blind; but while Hadranax was unarmored and navigated the deep sea using elongated frontal appendages, Palaeocampa anthrax, at just 4 cm long, bore a dense coat of spines — arranged above each pair of legs, giving it a fuzzy caterpillar-like appearance — and inhabited freshwater, possibly amphibious, environments.

The discovery also resolves the mystery of France’s Montceau-les-Mines fossil site, once considered as marine.

“Mazon Creek is a mix of terrestrial, freshwater, and marine animals,” Dr. Knecht explained.

“But, Montceau-les-Mines, where half of the specimens come from, was hundreds of km inland, with no ocean present.”

“Its reclassification confirms the site’s nonmarine setting, offering a rare glimpse into ancient freshwater ecosystems.”

This discovery broadens our understanding of lobopodian diversity and raises new evolutionary questions: How many others made the leap from marine to freshwater and could more be hiding, misidentified, in museum drawers?

“The conditions required to fossilize soft-bodied creatures like lobopodians are rare,” Dr. Knecht noted.

“Most of our insights come from Cambrian Lagerstätten, but the Carboniferous period — when Palaeocampa anthrax lived — offers far fewer such windows, making every new find incredibly valuable.”

The results appear in the journal Communications Biology.

_____

R.J. Knecht et al. 2025. Palaeocampa anthrax, an armored freshwater lobopodian with chemical defenses from the Carboniferous. Commun Biol 8, 1080; doi: 10.1038/s42003-025-08483-0

A century-old hypothesis that Betelgeuse, the 10th brightest star in our night sky, is orbited by a very close companion star was proved true by a team of astrophysicists led by a scientist at NASA’s Ames Research Center in California’s Silicon Valley.

The research published in The Astrophysical Journal Letters in the paper “Probable Direct Imaging Discovery of the Stellar Companion to Betelgeuse.”

Fluctuations in the brightness and measured velocity of Betelgeuse, the closest red supergiant star to Earth, had long presented clues that it may have a partner, but the bigger star’s intense glow made direct observations of any fainter neighbors nearly impossible.

Two recent studies by other teams of astronomers reignited the companion star hypothesis by using more than 100 years of Betelgeuse observations to provide predictions of the companion’s location and brightness.

If the smaller star did exist, the location predictions suggested that scientists had a window of just a few months to observe the companion star at its widest separation from Betelgeuse, as it orbited near the visible edge of the supergiant. After that, they would have to wait another three years for it to orbit to the other side and again leave the overpowering glow of its larger companion.

Searches for the companion were initially made using space-based telescopes, because observing through Earth’s atmosphere can blur images of astronomical objects. But these efforts did not detect the companion.

Steve Howell, a senior research scientist at Ames, recognized the ground-based Gemini North telescope in Hawai’i, one of the largest in the world, paired with a special, high-resolution camera built by NASA, had the potential to directly observe the close companion to Betelgeuse, despite the atmospheric blurring.

Officially called the ‘Alopeke speckle instrument, the advanced imaging camera let them obtain many thousands of short exposures to measure the atmospheric interference in their data and remove it with detailed image processing, providing an image of Betelgeuse and its companion.

Howell’s team detected the very faint companion star right where it was predicted to be, orbiting very close to the outer edge of Betelgeuse.

“I hope our discovery excites other astrophysicists about the robust power of ground-based telescopes and speckle imagers – a key to opening new observational windows,” said Howell. “This can help unlock the great mysteries in our universe.”

To start, this discovery of a close companion to Betelgeuse may explain why other similar red supergiant stars undergo periodic changes in their brightness on the scale of many years.

Howell plans to continue observations of Betelgeuse’s stellar companion to better understand its nature. The companion star will again return to its greatest separation from Betelgeuse in November 2027, a time when it will be easiest to detect.

Having found the long-anticipated companion star, Howell turned to giving it a name. The traditional star name “Betelgeuse” derives from Arabic, meaning “the hand of al-Jawza’,” a female figure in old Arabian legend. Fittingly, Howell’s team named the orbiting companion “Siwarha,” meaning “her bracelet.”

The NASA–National Science Foundation Exoplanet Observational Research Program (NN-EXPLORE) is a joint initiative to advance U.S. exoplanet science by providing the community with access to cutting-edge, ground-based observational facilities. Managed by NASA’s Exoplanet Exploration Program, NN-EXPLORE supports and enhances the scientific return of space missions such as Kepler, TESS (Transiting Exoplanet Survey Satellite), Hubble Space Telescope, and James Webb Space Telescope by enabling essential follow-up observations from the ground—creating strong synergies between space-based discoveries and ground-based characterization. NASA’s Exoplanet Exploration Program is located at the agency’s Jet Propulsion Laboratory.

To learn more about NN-EXPLORE, visit:

https://exoplanets.nasa.gov/exep/NNExplore/overview

An international team of scientists have provided an unprecedented tally of elemental sulfur spread between the stars using data from the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft.

Astronomers used X-rays from two binary star systems to detect sulfur in the interstellar medium, the gas and dust found in the space between stars. It’s the first direct measurement of both sulfur’s gas and solid phases, a unique capability of X-ray spectroscopy, XRISM’s (pronounced “crism”) primary method of studying the cosmos.

“Sulfur is important for how cells function in our bodies here on Earth, but we still have a lot of questions about where it’s found out in the universe,” said Lía Corrales, an assistant professor of astronomy at the University of Michigan in Ann Arbor. “Sulfur can easily change from a gas to a solid and back again. The XRISM spacecraft provides the resolution and sensitivity we need to find it in both forms and learn more about where it might be hiding.”

A paper about these results, led by Corrales, published June 27 in the Publications of the Astronomical Society of Japan.

Using ultraviolet light, researchers have found gaseous sulfur in the space between stars. In denser parts of the interstellar medium, such as the molecular clouds where stars and planets are born, this form of sulfur quickly disappears.

Scientists assume the sulfur condenses into a solid, either by combining with ice or mixing with other elements.

When a doctor performs an X-ray here on Earth, they place the patient between an X-ray source and a detector. Bone and tissue absorb different amounts of the light as it travels through the patient’s body, creating contrast in the detector.

To study sulfur, Corrales and her team did something similar.

They picked a portion of the interstellar medium with the right density — not so thin that all the X-rays would pass through unchanged, but also not so dense that they would all be absorbed.

Then the team selected a bright X-ray source behind that section of the medium, a binary star system called GX 340+0 located over 35,000 light-years away in the southern constellation Scorpius.

Using the Resolve instrument on XRISM, the scientists were able to measure the energy of GX 340+0’s X-rays and determined that sulfur was present not only as a gas, but also as a solid, possibly mixed with iron.

“Chemistry in environments like the interstellar medium is very different from anything we can do on Earth, but we modeled sulfur combined with iron, and it seems to match what we’re seeing with XRISM,” said co-author Elisa Costantini, a senior astronomer at the Space Research Organization Netherlands and the University of Amsterdam. “Our lab has created models for different elements to compare with astronomical data for years. The campaign is ongoing, and soon we’ll have new sulfur measurements to compare with the XRISM data to learn even more.”

Iron-sulfur compounds are often found in meteorites, so scientists have long thought they might be one way sulfur solidifies out of molecular clouds to travel through the universe.

Astronomers used X-rays from two binary star systems to detect sulfur in the interstellar medium, the gas and dust found in the space between stars. It’s the first direct measurement of both sulfur’s gas and solid phases, a unique capability of X-ray spectroscopy, XRISM’s (pronounced “crism”) primary method of studying the cosmos. — NASA

In their paper, Corrales and her team propose a few compounds that would match XRISM’s observations — pyrrhotite, troilite, and pyrite, which is sometimes called fool’s gold.

The researchers were also able to use measurements from a second X-ray binary called 4U 1630-472 that helped confirm their findings.

“NASA’s Chandra X-ray Observatory has previously studied sulfur, but XRISM’s measurements are the most detailed yet,” said Brian Williams, the XRISM project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since GX 340+0 is on the other side of the galaxy from us, XRISM’s X-ray observations are a unique probe of sulfur in a large section of the Milky Way. There’s still so much to learn about the galaxy we call home.”

XRISM is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). NASA and JAXA developed Resolve, the mission’s microcalorimeter spectrometer.

XRISM insights for interstellar sulfur, Publications of the Astronomical Society of Japan

Astrobiology, Astrochemistry, interstellar,

Researchers have identified a key neural switch that controls whether animals instinctively flee from a threat or freeze in place. By comparing two closely related deer-mouse species, they found that this switch is calibrated by evolution to match the animal’s habitat. This neural circuit is hypersensitive in mice living in densely vegetated environments, causing instant escape, but less responsive in their open-field cousins, who are more likely to freeze. In doing so, the research team uncovered an important way in which evolution fine-tunes the brain for survival.

Flee or freeze?

In nature, survival hinges on making the right split-second choice when danger strikes, and the brain’s defensive circuits are built for exactly that task. Yet what counts as the “right” response depends on the landscape: in cluttered woods, swift flight into the underbrush can save your life; on exposed grassland, motionless hiding buys time. How does evolution solve this puzzle? 

In a new study published in Nature, an international research team from Belgium and the USA has uncovered an elegant mechanism that, by tweaking the sensitivity of a danger-response hub in the brain, tailors behavior to each environment without redesigning the whole system.

Forest mice vs open-field mice

When a shadow of a potential predator looms overhead, forest mice (Peromyscus maniculatus) dash for cover, while their open-field cousins (Peromyscus polionotus) freeze in place. The researchers set out to pinpoint the brain switch that sets those opposite instincts.

To precisely measure escape behavior, we presented both types of mice with stimuli that resembled an aerial predator in a controlled environment. We found that open-field mice required roughly twice the stimulus intensity to trigger escape compared with their forest relatives, indicating a substantial difference in how they processed the threat stimulus.”

Felix Baier, co-first author and part of the research team at Harvard

A switch in the brain

Using cutting-edge neural recordings with Neuropixels probes and manipulation techniques, the researchers traced these behavioral differences to a central command hub for escape actions: the dorsal periaqueductal gray (dPAG), a group of neurons deep in the brain. “We were surprised to find that evolution acted in a central brain region, downstream of peripheral sensory perception, because for evolution to change a behavior, it has often been thought that the easiest and most efficient way would be to just change the sensory inputs,” says Baier.

Both species perceive the looming threat identically as evidenced by comparable responses along the circuit from the eye to the dPAG when the animals saw the stimulus without reacting to it. However, the activation of the dPAG differed significantly in the case where the mice escaped from the threat.

“Our monitoring of neural activity revealed a stark contrast: in forest deer mice, escaping from a potential threat in the sky is enabled by an instant ‘run’ command in the dPAG, whereas the dPAG of its open field cousin does not send any such commands. This divergence can be understood as an evolutionary repurposing of neural circuits to finetune survival response,” says Katja Reinhard, who is the other co-first author and a former postdoc at NERF (part of imec, KU Leuven and VIB), now leading her own group at SISSA, Italy.

Further, by using advanced methods that let scientists activate or silence specific brain regions, the team demonstrated a causal connection. Artificially stimulating dPAG neurons in forest mice made them escape even in the absence of a threat. Conversely, using chemical methods to dampen dPAG activity raised their escape threshold, making their behavior more like that of their cousins. 

Built-in flexibility

The study not only sheds light on how instinctive behaviors like freezing or fleeing are controlled but also underscores the flexibility of the brain’s internal architecture, explain lead authors Prof. Karl Farrow (imec, KU Leuven, VIB) and Prof. Hopi Hoekstra (Harvard).

Farrow: “By comparing these two related species we uncovered a switch that balances freeze versus flight, showing how natural selection fine-tunes behavior without rewiring the senses.”

Hoekstra: “Our new discovery illustrates a fundamental evolutionary principle: natural selection often tweaks existing neural circuits rather than constructing entirely new pathways.”

A new Chinese freighter spacecraft arrived at the Tiangong space station last week, packed with supplies.

Tianzhou 9 launched July 14 atop a Long March 7 rocket at 5:34 p.m. EDT (2134 GMT; 5:34 a.m. on July 15 China Standard Time), sending the spacecraft into orbit. Just over three hours later, at 8:52 p.m. EDT (0052 GMT; 8:52 p.m. China Standard Time on July 15), Tianzhou 9 docked at the rear docking port of the Tiangong space station’s Tianhe core module, according to China’s human spaceflight agency, CMSA.

The Extraterrestrial Materials Analysis Group (ExMAG) meeting is scheduled for September 15–19, 2025, at the Lunar and Planetary Institute (LPI) in Houston, Texas.

The Second ExMAG/MEPAG Joint Workshop: Connecting Community Scientific Hypotheses to Mars Sample Science, which was scheduled for September 18–19, 2025, has been merged into this ExMAG meeting.

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Travel and participation support for student and early-career attendees is available. Visit the ExMAG meeting website for eligibility requirements and the online application form.

Application deadline: August 8, 2025

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https://www.lpi.usra.edu/exmag/meetings/exmagmay2025

Astrobiology, Astrochemistry, Astrogeology,