NASA’s Hubble sees white dwarf eating piece of Pluto-like object
In our nearby stellar neighborhood, a burned-out star is snacking on a fragment of a Pluto-like object. With its unique ultraviolet capability, only NASA’s Hubble Space Telescope could identify that this meal is taking place.
image:
This artist's concept shows a white dwarf surrounded by a large debris disk. Debris from pieces of a captured, Pluto-like object is falling onto the white dwarf.
view moreCredit: Artwork: NASA, Tim Pyle (NASA/JPL-Caltech)
In our nearby stellar neighborhood, a burned-out star is snacking on a fragment of a Pluto-like object. With its unique ultraviolet capability, only NASA’s Hubble Space Telescope could identify that this meal is taking place.
The stellar remnant is a white dwarf about half the mass of our Sun, but that is densely packed into a body about the size of Earth. Scientists think the dwarf’s immense gravity pulled in and tore apart an icy Pluto analog from the system’s own version of the Kuiper Belt, an icy ring of debris that encircles our solar system. The findings were reported on September 18 in the Monthly Notices of the Royal Astronomical Society.
The researchers were able to determine this carnage by analyzing the chemical composition of the doomed object as its pieces fell onto the white dwarf. In particular, they detected “volatiles” — substances with low boiling points — including carbon, sulphur, nitrogen, and a high oxygen content that suggests the strong presence of water.
“We were surprised,” said Snehalata Sahu of the University of Warwick in the United Kingdom. Sahu led the data analysis of a Hubble survey of white dwarfs. “We did not expect to find water or other icy content. This is because the comets and Kuiper Belt-like objects are thrown out of their planetary systems early, as their stars evolve into white dwarfs. But here, we are detecting this very volatile-rich material. This is surprising for astronomers studying white dwarfs as well as exoplanets, planets outside our solar system."
Only with Hubble
Using Hubble’s Cosmic Origins Spectrograph, the team found that the fragments were composed of 64 percent water ice. The fact that they detected so much ice meant that the pieces were part of a very massive object that formed far out in the star system’s icy Kuiper Belt analog. Using Hubble data, scientists calculated that the object was bigger than typical comets and may be a fragment of an exo-Pluto.
They also detected a large fraction of nitrogen – the highest ever detected in white dwarf debris systems. “We know that Pluto's surface is covered with nitrogen ices,” said Sahu. “We think that the white dwarf accreted fragments of the crust and mantle of a dwarf planet.”
Accretion of these volatile-rich objects by white dwarfs is very difficult to detect in visible light. These volatile elements can only be detected with Hubble’s unique ultraviolet light sensitivity. In optical light, the white dwarf would appear ordinary.
About 260 light-years away, the white dwarf is a relatively close cosmic neighbor. In the past, when it was a Sun-like star, it would have been expected to host planets and an analog to our Kuiper Belt.
Like seeing our Sun in future
Billions of years from now, when our Sun burns out and collapses to a white dwarf, Kuiper Belt objects will be pulled in by the stellar remnant’s immense gravity. “These planetesimals will then be disrupted and accreted,” said Sahu. “If an alien observer looks into our solar system in the far future, they might see the same kind of remains we see today around this white dwarf.”
The team hopes to use NASA’s James Webb Space Telescope to detect molecular features of volatiles such as water vapor and carbonates by observing this white dwarf in infrared light. By further studying white dwarfs, scientists can better understand the frequency and composition of these volatile-rich accretion events.
Sahu is also following the recent discovery of the interstellar comet 3I/ATLAS. She is eager to learn its chemical composition, especially its fraction of water. “These types of studies will help us learn more about planet formation. They can also help us understand how water is delivered to rocky planets,” said Sahu.
Boris Gänsicke, of the University of Warwick and a visitor at Spain’s Instituto de Astrofisica de Canarias, was the principal investigator of the Hubble program that led to this discovery. “We observed over 500 white dwarfs with Hubble. We’ve already learned so much about the building blocks and fragments of planets, but I’ve been absolutely thrilled that we now identified a system that resembles the objects in the frigid outer edges of our solar system,” said Gänsicke. “Measuring the composition of an exo-Pluto is an important contribution toward our understanding of the formation and evolution of these bodies.”
The Hubble Space Telescope has been operating for more than 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, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
To learn more about Hubble, visit: https://science.nasa.gov/hubble
Journal
Monthly Notices of the Royal Astronomical Society
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Discovery of an icy and nitrogen-rich extrasolar planetesimal
Article Publication Date
18-Sep-2025
Naval Research Laboratory robotic servicing payload clears thermal vacuum lab test, readies for space
Naval Research Laboratory
image:
The Robotic Servicing of Geosynchronous Satellites (RSGS) payload integrated with the Northrop Grumman Mission Robotics Vehicle (MRV) spacecraft bus moves into the cryogenic thermal vacuum chamber for testing at the U.S. Naval Research Laboratory’s (NRL) Naval Center for Space Technology (NCST) in Washington, D.C., July 24, 2025. NRL NCST, with funding support from the Defense Advanced Research Projects Agency (DARPA), is conducting final space-readiness testing on RSGS, a robotic payload designed to extend and upgrade satellites already in orbit.
view moreCredit: U.S. Navy photo by Sarah Peterson
WASHINGTON, D.C. – The U.S. Naval Research Laboratory (NRL), in partnership with and with funding support from the Defense Advanced Research Projects Agency (DARPA) and Northrop Grumman’s SpaceLogistics, has reached a historic milestone in satellite servicing technology, completing on Sept. 5 a critical round of space-readiness testing on a robotic spacecraft designed to extend and upgrade satellites already in orbit.
The testing, known as thermal vacuum (TVAC), confirmed the Robotic Servicing of Geosynchronous Satellites (RSGS) payload integrated with the Northrop Grumman SpaceLogistics Mission Robotic Vehicle (MRV) spacecraft bus can withstand the punishing heat, cold, and vacuum conditions of space. With the test complete, the system will be sent back to Northrop Grumman for final checks before shipment to the launch site.
“This is more than a successful test, we are nearing the culmination of decades of work and partnership that began as a vision for on-orbit servicing and it’s exciting to be so close to this technology being space-qualified and ready for flight,” said Bernard Kelm, acting director of the Naval Center for Space Technology. “The partnership between NRL’s spacecraft engineering expertise, DARPA’s vision, and Northrop Grumman’s commercial space operations expertise have built a system that will transform how we think about satellite operations in geosynchronous orbit.”
From idea to spaceflight hardware
The RSGS program is the result of over 20 years of research and development at NRL, aimed at creating robotic systems capable of repairing and upgrading satellites in geosynchronous orbit, roughly 22,000 miles above Earth. As a public private partnership between DARPA and Northrop Grumman’s SpaceLogistics the NRL-developed robotic servicing payload is designed to enable close inspections, orbital adjustments, hardware upgrades, and even in-orbit repairs.
“The completion of spacecraft thermal vacuum testing marks the most critical milestone of recognizing the NRL-developed payload and MRV are capable of working together as a system,” said Dr. Bruce Danly, NRL director of research. “This capability has the potential to extend satellite lifespans, reduce costs, and further enable entirely new types of missions.”
A new era of space resilience
Until now, satellites have been built with costly backup systems because they could not be repaired or upgraded once launched. RSGS changes that equation.
“This program has always been about more than hardware, it’s about the collaboration and dedication of an extraordinary team,” said Jim Barnds, NRL RSGS program manager. “NRL not only engineered the robotic payload and its components but also shaped the mission design, flight operations, and detailed modeling and simulation that make this capability viable for both government and commercial operations.”
“As the payload heads toward launch, we’re proud to see years of effort turn into a capability where the spacecraft and payload will enable over a decade of servicing opportunities”, Barnds said. “This is going to change the way the world approaches space operations,” he added.
NRL scientists and engineers spent years maturing the technology and working on the engineering design for this mission. RSGS is designed with Department of Defense reliability standards, including redundant robotic arms, avionics, and mission tools. The system carries a sophisticated Rendezvous and Proximity Operations suite with multiple cameras, sensors, and infrared imaging to allow safe approach and servicing to client satellites. Two robotic arms, equipped with lights, cameras, and tool changers, will execute capture, inspection, and upgrade tasks using specialized tools with the capability of adding new tools after launch if needed. By enabling routine service, it promises longer lifespans, lower costs, and new opportunities for innovation in space infrastructure.
Looking ahead to launch
Following completion of TVAC at NRL, the spacecraft will undergo final integrated systems testing this Fall at Northrop Grumman’s facility in Dulles, Virginia.
Once in orbit, the MRV and payload will enter checkout before beginning proximity operations, rendezvous, and client servicing demonstrations. Tasks will range from anomaly resolution and orbit modification to upgrades and inspections, proving the ability to extend and enhance satellite service life.
With launch preparations starting soon, RSGS is poised to demonstrate its robotic capabilities in orbit for the first time, marking the beginning of a new era in resilient space operations.
About the U.S. Naval Research Laboratory
NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL, located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.
For more information, contact NRL Corporate Communications at (202) 480-3746 or nrlpao@us.navy.mil.
The Robotic Servicing of Geosynchronous Satellites (RSGS) payload integrated with the Northrop Grumman Mission Robotics Vehicle (MRV) spacecraft bus sits in the cryogenic thermal vacuum chamber for testing at the U.S. Naval Research Laboratory’s (NRL) Naval Center for Space Technology (NCST) in Washington, D.C., July 28, 2025. NRL NCST, with funding support from the Defense Advanced Research Projects Agency (DARPA), is conducting final space-readiness testing on RSGS, a robotic payload designed to extend and upgrade satellites already in orbit.
Credit
U.S. Navy photo by Sarah Peterson
Galaxies reveal hidden maps of dark matter in the early universe
Rutgers researchers uncover “fingerprints” that show how these cosmic systems expand and evolve
Rutgers University
image:
Schematic of the night sky areas are outlined with contour lines, similar to elevation lines on a hiking map, revealing the “fingerprints” of dark matter.
view moreCredit: Eric Gawiser, Dani Herrera/Rutgers University
A Rutgers-led team of scientists has uncovered evidence of how galaxies expand by tracing the invisible scaffolding of the universe created by a mysterious substance known as dark matter.
In a newly published study in Astrophysical Journal Letters, researchers used what they said are the largest-ever samples of special galaxies called Lyman-alpha emitters to study how galaxies clumped together over billions of years. In doing so, they gained an improved understanding of how galaxies relate to the surrounding dark matter and how they evolve over time.
“Analyzing these fingerprints gives us insight into the mass of dark matter surrounding the galaxies,” said Eric Gawiser, a Distinguished Professor with the Department of Physics and Astronomy in the Rutgers School of Arts and Sciences and an author of the study. “The dark matter masses revealed by this study are consistent with the idea that Lyman-alpha emitting galaxies evolved into present-day galaxies like our own Milky Way.”
The analysis, which assessed wide-field images across three different eras of the universe’s history shortly after the Big Bang, revealed distinct patterns, akin to cosmic fingerprints. These patterns point to where dark matter is most concentrated, the researchers said.
Dark matter, a mysterious substance that doesn’t emit light or energy, cannot be seen, but makes up most of the matter in the universe, according to scientists. They know dark matter exists because its gravity affects how galaxies move and how these vast cosmic systems are arranged in space.
The study, led by Rutgers doctoral student Dani Herrera, used data from the ODIN (One-hundred-square-degree DECam Imaging in Narrowbands) survey, which is a large astronomical project designed to analyze more than 100,000 Lyman-alpha emitting galaxies.
The researchers focused on data taken from a region of the sky known as the Cosmic Evolution Survey Deep Field (COSMOS), in one of the largest deep-sky surveys ever conducted. Looking deep into space and into the distant past, they viewed three time periods, some 2.8 billion, 2.1 billion and 1.4 billion years after the Big Bang. During these periods, Lyman-alpha emitter galaxies were young and actively forming stars, making them ideal markers for study. They also contain hydrogen gas that emits a special glow, which allows scientists to discover large numbers of them in the distant universe.
“We wanted to find the dark matter whose gravity drives galaxies to merge and grow,” Herrera said. “Understanding where it is and how it has evolved helps us understand how the universe itself has evolved.”
Dark matter plays a crucial role in galaxy formation by acting as a gravitational “glue” that helps pull gas together to form galaxies, Herrera said. Its invisible mass creates deep wells in space where galaxies can grow, merge and evolve, forming the large-scale structure of the universe.
“We used the clumpiness of these galaxies to identify where the dark matter was densest,” Gawiser said. “Visualizing that with a contour map, much the way that a hiking map shows elevations, lets us observe the ‘fingerprints’ of dark matter in the distant universe.”
One result stood out. Three percent to 7% of the dense regions of dark matter capable of hosting galaxies contain Lyman-alpha emitting galaxies, they found. This means that Lyman-alpha emitting galaxies represent a small percentage of the galaxies forming where the dark matter is densest. The low percentage hints that the galaxies were observed during a short-lived phase, glowing in Lyman-alpha light for tens to hundreds of millions of years.
To uncover these results, the researchers used a technique called clustering which measures how galaxies are grouped compared with random distributions. They calculated the angular correlation function, a method of counting pairs of galaxies.
This research, the scientists said, not only deepens understanding of galaxy evolution but also helps scientists refine models of the universe’s structure. As the ODIN survey continues, future studies will expand to more galaxies, offering a more complete view of the cosmic web, they said.
“While invisible to our telescopes, dark matter shapes the universe through interactions with visible material,” Gawiser said. “While some try to understand what it is, others like this research team try to understand where it is and what that implies about the evolution of the universe.”
Journal
The Astrophysical Journal Letters
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
ODIN: Clustering Analysis of 14,000 Lyα-emitting Galaxies at z = 2.4, 3.1, and 4.5
Water flowed on ancient asteroid
Liquid water on asteroids reshapes our understanding of the early solar system
image:
Diagram to show how the researchers think the evolution of Ryugu played out over at least a billion years. ©2025 Iizuka et al. CC-BY-ND
view moreCredit: ©2025 Iizuka et al. CC-BY-ND
A team of researchers, including those at the University of Tokyo, discovered that liquid water once flowed on the asteroid that spawned near-Earth asteroid Ryugu more than a billion years after it first formed. The finding, based on tiny rock fragments returned by the Hayabusa2 spacecraft of the Japan Aerospace Exploration Agency (JAXA), overturns long-held assumptions that water activity on asteroids only occurred in the earliest moments of solar system history. This could impact models which include the formation of the Earth.
We have a relatively good understanding of how the solar system formed, but of course there are many gaps. One such gap in our knowledge is how Earth came to possess so much water. It’s long been known that so-called carbonaceous asteroids like Ryugu formed from ice and dust in the outer solar system supplied water to Earth. Ryugu was famously visited by the Hayabusa2 spacecraft in 2018, the first visit of its kind, where not only were in-situ data collected, but small samples of material were brought back to Earth too. And it’s thanks to this endeavor that researchers can help fill in some missing details in the picture of our creation.
“We found that Ryugu preserved a pristine record of water activity, evidence that fluids moved through its rocks far later than we expected,” said Associate Professor Tsuyoshi Iizuka from the Department of Earth and Planetary Science at the University of Tokyo. “This changes how we think about the long-term fate of water in asteroids. The water hung around for a long time and was not exhausted so quickly as thought.”
The heart of the discovery comes from the analysis of isotopes of lutetium (Lu) and hafnium (Hf), whose radioactive decay from 176Lu to 176Hf can serve as a sort of clock for measuring geological processes. Their presence in certain quantities in the samples studied was expected to relate to the age of the asteroid in a fairly predictable way. But the ratio of 176Hf to 176Lu was far higher than anticipated. This strongly implied to the researchers that a fluid was essentially washing out the lutetium from the rocks containing it.
“We thought that Ryugu’s chemical record would resemble certain meteorites already studied on Earth,” said Iizuka. “But the results were completely different. This meant we had to carefully rule out other possible explanations and eventually concluded that the Lu-Hf system was disturbed by late fluid flow. The most likely trigger was an impact on a larger asteroid parent of Ryugu, which fractured the rock and melted buried ice, allowing liquid water to percolate through the body. It was a genuine surprise! This impact event may be also responsible for the disruption of the parent body to form Ryugu.”
One of the most important implications is that carbon-rich asteroids may have contained and delivered much more water to Earth than previously thought. It seems Ryugu’s parent body retained ice for over a billion years, meaning similar bodies striking a young Earth could have carried an estimated two to three times more water than standard models account for, significantly affecting our planet’s early oceans and atmosphere.
“The idea that Ryugu-like objects held on to ice for so long is remarkable,” said Iizuka. “It suggests that the building blocks of Earth were far wetter than we imagined. This forces us to rethink the starting conditions for our planet’s water system. Though it’s too early to say for sure, my team and others might build on this research to clarify things, including how and when our Earth became habitable.”
Hayabusa2 only brought back a few grams of material. With many researchers wanting to run tests on it, each experiment could only use a few tens of milligrams, fractions of a grain of rice. To maximize the information gained, the team developed sophisticated methods for separating elements and analyzing isotopes with extraordinary precision, realizing the full potential of current geochemical analytical techniques.
“Our small sample size was a huge challenge,” recalled Iizuka. “We had to design new chemistry methods that minimized elemental loss while still isolating multiple elements from the same fragment. Without this, we could never have detected such subtle signs of late fluid activity.”
The researchers also plan to study phosphate veins within Ryugu samples to pin down more precise ages of the late fluid flow. They will also compare their results with NASA’s samples collected from asteroid Bennu by the OSIRIS-REx spacecraft, to test whether similar water activity might have happened there too, or whether it was unique to Ryugu. Eventually, Iizuka and colleagues hope to trace how water was stored, mobilized and finally delivered to Earth, a story that continues to shape our understanding of planetary habitability.
###
Journal: Tsuyoshi Iizuka, Takazo Shibuya, Takehito Hayakawa, Tetsuya Yokoyama, Ikshu Gautam, Makiko K. Haba, Kengo T. M. Ito, Yuki Hibiya, Akira Yamaguchi, Yoshinari Abe, Jérôme Aléon, Conel M. O’D. Alexander, Sachiko Amari, Yuri Amelin, Ken-ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W. Carlson, Marc Chaussidon, Byeon-Gak Choi, Nicolas Dauphas, Andrew M. Davis, Tommaso Di Rocco, Wataru Fujiya, Ryota Fukai, Hiroshi Hidaka, Hisashi Homma, Gary R. Huss, Trevor R. Ireland, Akira Ishikawa, Shoichi Itoh, Noriyuki Kawasaki, Noriko T. Kita, Koki Kitajima, Thorsten Kleine, Shintaro Komatani, Alexander N. Krot, Ming-Chang Liu, Yuki Masuda, Kazuko Motomura, Frédéric Moynier, Kazuhide Nagashima, Izumi Nakai, Ann Nguyen, Larry Nittler, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, Sara Russell, Naoya Sakamoto, Maria Schönbächler, Lauren Tafla, Haolan Tang, Kentaro Terada, Yasuko Terada, Tomohiro Usui, Sohei Wada, Meenakshi Wadhwa, Richard J. Walker, Katsuyuki Yamashita, Qing-Zhu Yin, Shigekazu Yoneda, Hiroharu Yui, Ai-Cheng Zhang, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tatsuaki Okada, Toru Yada, Kasumi Yogata, Satoru Nakazawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Sei-ichiro Watanabe, Makoto Yoshikawa, Shogo Tachibana, Hisayoshi Yurimoto, “Late fluid flow in a primitive asteroid revealed by Lu–Hf isotopes in Ryugu”, Nature, https://doi.org/10.1038/s41586-025-09483-0
Funding: This work was supported by Japan Society for the Promotion of Science KAKENHI grants (21KK0057, 22H00170).
Useful links:
Graduate School of Science - https://www.s.u-tokyo.ac.jp/en/
Department of Earth and Planetary Science - https://www.eps.s.u-tokyo.ac.jp/en/
Ryugu is named after a magical underwater palace in a Japanese folktale — appropriately enough it seems to be a palace for water in the real world too. ©2025 Jaxa, UTokyo & collaborators CC-BY-ND
Credit
©2025 Jaxa, UTokyo & collaborators CC-BY-ND
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 5,000 international students. Find out more at www.u-tokyo.ac.jp/en/ or follow us on X (formerly Twitter) at @UTokyo_News_en.
Journal
Nature
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Late fluid flow in a primitive asteroid revealed by Lu–Hf isotopes in Ryugu
Article Publication Date
18-Sep-2025
Gemini data critical to revealing that Hayabusa2 target is tinier and faster than thought
Gemini South paves the way for characterizing small asteroids from the ground with new data on spacecraft Hayabusa2’s asteroid target, 1998 KY26
Association of Universities for Research in Astronomy (AURA)
image:
The tiny asteroid 1998 KY26 (center) is observed here by 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.
The observations have revealed that 1998 KY26 is just 11 meters wide, almost three times smaller than previously thought, and is spinning once every 5 minutes, which is almost two times faster than expected.
This image is composed of exposures taken through four filters. As exposures are taken, the asteroid remains fixed in the center of the telescope’s field of view. However, the positions of the background stars change relative to the asteroid, causing them to appear as colorful streaks in the final image.
view moreCredit: International Gemini Observatory/NOIRLab/NSF/AURA/T. Santana-Ros
Astronomers using observatories around the world, including the Gemini South telescope, the SOAR telescope and the Víctor M. Blanco 4-meter Telescope funded in part by the U.S. National Science Foundation and operated by NSF NOIRLab, have found that the asteroid 1998 KY26 is almost three times smaller and spinning much faster than previously thought. The asteroid is the 2031 target for Japan’s Hayabusa2 extended mission, and the new observations offer key information for the mission’s operations.
“We found that the reality of the object is completely different from what it was previously described as,” says astronomer Toni Santana-Ros, a researcher from the University of Alicante, Spain. The new observations, combined with previous radar data, have revealed that the asteroid, 1998 KY26, is just 11 meters wide. It is also spinning about twice as fast as previously thought: “One day on this asteroid lasts only five minutes!" he says. Previous data indicated that the asteroid was around 30 meters in diameter and completed a rotation in approximately 10 minutes. The smaller size and faster rotation will make the spacecraft’s touchdown maneuver more difficult to perform than anticipated.
1998 KY26 is set to be the final target asteroid for the Japanese Aerospace eXploration Agency (JAXA)’s Hayabusa2 spacecraft. In its original mission, Hayabusa2 explored the 900-meter-diameter asteroid 162173 Ryugu in 2018, returning asteroid samples to Earth in 2020. With fuel remaining, the spacecraft was sent on an extended mission until 2031, when it’s set to encounter 1998 KY26, aiming to learn more about the smallest asteroids. This will be the first time a space mission encounters a tiny asteroid — all previous missions visited asteroids with diameters in the hundreds or even thousands of meters.
Santana-Ros and his team observed 1998 KY26 from the ground [1] to support the preparation of the mission. Because the asteroid is very small and, hence, very faint, studying it required waiting for a close encounter with Earth and the use of large telescopes, like Gemini South, SOAR, the NSF Víctor M. Blanco Telescope and European Southern Observatory's Very Large Telescope. Gemini was the only telescope observing the object through multiple filters, which proved crucial for its characterization. Gemini South is one half of the International Gemini Observatory, funded in part by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab.
The observations revealed that the asteroid has a bright surface and likely consists of a solid chunk of rock, which may have originated from a piece of a planet or another asteroid. However, the team could not completely rule out the possibility that the asteroid is composed of rubble piles loosely sticking together. “We have never seen a ten-meter-sized asteroid in situ, so we don't really know what to expect and how it will look,” says Santana-Ros, who is also affiliated with the University of Barcelona.
“The amazing story here is that the size of the asteroid is comparable to the size of the spacecraft that is going to visit it! And we were able to characterize such a small object using our telescopes, which means that we can do it for other objects in the future,” says Santana-Ros. “Our methods could have an impact on the plans for future near-Earth asteroid exploration or even asteroid mining.”
Notes
[1] The telescopes include Gemini South with the Gemini Multi-Object Spectrograph (GMOS), Southern Astrophysical Research (SOAR) Telescope, the NSF Víctor M. Blanco Telescope with the Dark Energy Camera (DECam), European Southern Observatory's Very Large Telescope (VLT) with FOcal Reducer and low dispersion Spectrograph 2 (FORS2), and Gran Telescopio CANARIAS (GTC) with the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) instrument.
More information
This research was presented in a paper titled “Hayabusa2 extended mission target asteroid 1998 KY26 is smaller and rotating faster than previously known” to appear in Nature Communications (doi: 10.1038/s41467-025-63697-4).
The team is composed of T. Santana-Ros (Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal, Universidad de Alicante, and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona (IEEC-UB), Spain), P. Bartczak (Instituto Universitario de Física Aplicada a las Ciencias y a las Tecnologías, Universidad de Alicante, Spain and Astronomical Observatory Institute, Faculty of Physics and Astronomy, A. Mickiewicz University, Poland [AOI AMU]), K. Muinonen (Department of Physics, University of Helsinki, Finland [Physics UH]), A. Rożek (Institute for Astronomy, University of Edinburgh, Royal Observatory Edinburgh, UK [IfA UoE]), T. Müller (Max-Planck-Institut für extraterrestrische Physik, Germany), M. Hirabayashi (Georgia Institute of Technology, United States), D. Farnocchia (Jet Propulsion Laboratory, California Institute of Technology, USA [JPL]), D. Oszkiewicz (AOI AMU), M. Micheli (ESA ESRIN / PDO / NEO Coordination Centre, Italy), R. E. Cannon (IfA UoE), M. Brozovic (JPL), O. Hainaut (European Southern Observatory, Germany), A. K. Virkki [Physics UH], L. A. M. Benner (JPL), A. Cabrera-Lavers (GRANTECAN and Instituto de Astrofísica de Canarias, Spain), C. E. Martínez-Vázquez (International Gemini Observatory/NSF NOIRLab, USA), K. Vivas (Cerro Tololo Inter-American Observatory/NSF NOIRLab, Chile).
NSF NOIRLab, the U.S. National Science Foundation center for ground-based optical-infrared astronomy, operates the International Gemini Observatory (a facility of NSF, NRC–Canada, ANID–Chile, MCTIC–Brazil, MINCyT–Argentina, and KASI–Republic of Korea), NSF Kitt Peak National Observatory (KPNO), NSF Cerro Tololo Inter-American Observatory (CTIO), the Community Science and Data Center (CSDC), and NSF–DOE Vera C. Rubin Observatory (in cooperation with DOE’s SLAC National Accelerator Laboratory). It is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with NSF and is headquartered in Tucson, Arizona.
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.
Links
- Read the paper: https://www.nature.com/articles/s41467-025-63697-4
- ESO press release
- Check out other NOIRLab Science Releases
An artist's impression of Japan’s Hayabusa2 space mission touching down on the surface of the asteroid 1998 KY26. New observations 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, and ESO’s Very Large Telescope (VLT) have revealed that 1998 KY26 is just 11 meter wide, almost three times smaller than previously thought, and is spinning once every 5 minutes, which is almost two times faster than expected. The image above shows an updated size comparison between the asteroid and spacecraft.
Credit
ESO/M. Kornmesser. Asteroid: T. Santana-Ros et al. Hayabusa2 model: SuperTKG (CC-BY-SA)
Here is an artist’s impression of the size difference between the previous target asteroid for Japan’s Hayabusa2 space mission, 162173 Ryugu, and 1998 KY26. Hayabusa2 collected samples from Ryugu in 2018, returning them to Earth in 2020. After this successful mission, 1998 KY26 was chosen as Hayabusa2’s next target. Now, a new study using 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, and ESO’s Very Large Telescope (VLT) has shown that this asteroid is only 11 m wide, making it a much more difficult asteroid to touch down on than previously thought.
Credit
ESO/M. Kornmesser. Asteroid models: T. Santana-Ros, JAXA/University of Aizu/Kobe University
Journal
Nature Communications
Method of Research
Observational study
Subject of Research
Not applicable
Article Title
Hayabusa2 extended mission target asteroid 1998 KY26 is smaller and rotating faster than previously known
Article Publication Date
18-Sep-2025
By AFP
September 18, 2025
Taiwan needs 150 of its own low Earth orbit (LEO) satellites for "basic communication resilience" in case the subsea telecoms cables connecting the island with the rest of the world are damaged or cut - Copyright AFP Ronan LIETAR
Allison Jackson and Akio Wang
Taiwan’s space chief Wu Jong-shinn says the “clock is ticking” for the democratic island to launch its own satellites to secure internet and phone services during a potential conflict with China.
The island faces the constant threat of an invasion by Beijing, which claims the island is part of its territory and in recent years has intensified military pressure.
Taiwan needs 150 of its own low Earth orbit (LEO) satellites for “basic communication resilience” in case the subsea telecoms cables connecting the island with the rest of the world are damaged or cut, Wu told AFP in an interview.
It currently has none.
“We need to build up our own technology. But as you know… the clock is ticking,” said Wu, director general of Taiwan Space Agency.
“We need to speed up.”
Taiwanese authorities have already seen what happens when subsea cables are disconnected.
In February 2023, two telecoms lines serving Taiwan’s outlying Matsu archipelago were severed, disrupting communications for weeks.
Taiwan plans to launch the first of six LEO satellites 600 kilometres (373 miles) above the planet in 2027 as part of its Beyond 5G LEO Satellite programme.
US officials have previously cited 2027 as a possible timeline for a Chinese invasion of Taiwan.
In the meantime, Taiwan’s Chunghwa Telecom is striking deals with satellite companies around the world to provide back-up telecommunications for the island in case of a war or natural disaster.
Starlink dominates the satellite communications sector, with 8,000 satellites lofted into orbit by Elon Musk’s comparatively cheap, reusable SpaceX rockets.
But Musk’s business ties with China and his previous comments that Taiwan should become part of China have angered the island.
Taiwan instead has signed a multi-million dollar deal with European company Eutelsat, the world’s second-largest operator of LEO satellites.
Eutelsat has more than 600 satellites, following its 2023 merger with British firm OneWeb.
“We’re developing our own technology, but it takes a while, but we can leverage the commercial resources to get us to have this communication resilience,” Wu said.
But Wu said Eutelsat’s satellites were not enough and other providers were needed.
Taiwan has also partnered with US company Astranis and SES of Luxembourg, and is in talks with Amazon’s Kuiper and Canada’s Telesat.
Eutelsat’s satellite system was reportedly used in a Taiwan disaster for the first time in 2024 when a deadly 7.4-magnitude earthquake struck the east coast and knocked out communications.
– ‘We can’t rely on one side’ –
Taiwan is light years behind the the US and Chinese space programmes.
The rival superpowers have ploughed billions of dollars sending people into orbit and launching thousands of satellites.
Taiwan currently has seven meteorological satellites and one optical remote sensing satellite in orbit, and hopes to have “more than 20” by around 2031, Wu said.
It plans to launch a second optical remote sensing satellite in November from the Vandenberg Space Force Base in California on a SpaceX rocket.
Wu said Taiwan would have its own rockets and launch site in the next decade.
When it comes to communication satellites, however, some question the economic sense of countries developing their own networks when commercial options are available.
“If you want this to work, you need a large number of them in low Earth orbit for that continuous coverage,” Brad Tucker, an astrophysicist and cosmologist at the Australian National University, told AFP.
“You have to be committed to this long-term operation but also then you need to maintain it. Starlink works because they are de-orbiting their satellites every three years, putting up a new one.”
But Taiwanese expert Cathy Fang said it would be “dangerous” for Taiwan to rely only on foreign satellite operators for phone and internet signal during a war.
Taiwan has learned lessons from Ukraine where Starlink has been a vital communications tool for Ukrainian forces fighting Moscow’s troops.
Musk has admitted blocking a Ukraine attack on Russian warships by turning off internet access to the system.
“We can’t just rely on one side,” Fang, a policy analyst at the government-backed Research Institute for Democracy, Society and Emerging Technology, told AFP.
“We need to cultivate our industry.”
Could a primordial black hole’s last burst explain a mysteriously energetic neutrino?
If a new proposal by MIT physicists bears out, the recent detection of a record-setting neutrino could be the first evidence of elusive Hawking radiation.
Massachusetts Institute of Technology
The last gasp of a primordial black hole may be the source of the highest-energy “ghost particle” detected to date, a new MIT study proposes.
In a paper appearing today in Physical Review Letters, MIT physicists put forth a strong theoretical case that a recently observed, highly energetic neutrino may have been the product of a primordial black hole exploding outside our solar system.
Neutrinos are sometimes referred to as ghost particles, for their invisible yet pervasive nature: They are the most abundant particle type in the universe, yet they leave barely a trace. Scientists recently identified signs of a neutrino with the highest energy ever recorded, but the source of such an unusually powerful particle has yet to be confirmed.
The MIT researchers propose that the mysterious neutrino may have come from the inevitable explosion of a primordial black hole. Primordial black holes (PBHs) are hypothetical black holes that are microscopic versions of the much more massive black holes that lie at the center of most galaxies. PBHs are theorized to have formed in the first moments following the Big Bang. Some scientists believe that primordial black holes could constitute most or all of the dark matter in the universe today.
Like their more massive counterparts, PBHs should leak energy and shrink over their lifetimes, in a process known as Hawking radiation, which was predicted by the physicist Stephen Hawking. The more a black hole radiates, the hotter it gets and the more high-energy particles it releases. This is a runaway process that should produce an incredibly violent explosion of the most energetic particles just before a black hole evaporates away.
The MIT physicists calculate that, if PBHs make up most of the dark matter in the universe, then a small subpopulation of them would be undergoing their final explosions today throughout the Milky Way galaxy. And, there should be a statistically significant possibility that such an explosion could have occurred relatively close to our solar system. The explosion would have released a burst of high-energy particles, including neutrinos, one of which could have had a good chance of hitting a detector on Earth.
If such a scenario had indeed occurred, the recent detection of the highest-energy neutrino would represent the first observation of Hawking radiation, which has long been assumed, but has never been directly observed from any black hole. What’s more, the event might indicate that primordial black holes exist and that they make up most of dark matter — a mysterious substance that comprises 85 percent of the total matter in the universe, the nature of which remains unknown.
“It turns out there’s this scenario where everything seems to line up, and not only can we show that most of the dark matter [in this scenario] is made of primordial black holes, but we can also produce these high-energy neutrinos from a fluke nearby PBH explosion,” says study lead author Alexandra Klipfel, a graduate student in MIT’s Department of Physics. “It’s something we can now try to look for and confirm with various experiments.”
The study’s other co-author is David Kaiser, professor of physics and the Germeshausen Professor of the History of Science at MIT.
High-energy tension
In February, scientists at the Cubic Kilometer Neutrino Telescope, or KM3NeT, reported the detection of the highest-energy neutrino recorded to date. KM3NeT is a large-scale underwater neutrino detector located at the bottom of the Mediterranean Sea, where the environment is meant to mute the effects of any particles other than neutrinos.
The scientists operating the detector picked up signatures of a passing neutrino with an energy of over 100 peta-electron-volts. One peta-electron volt is equivalent to the energy of 1 quadrillion electron volts.
“This is an incredibly high energy, far beyond anything humans are capable of accelerating particles up to,” Klipfel says. “There’s not much consensus on the origin of such high-energy particles.”
Similarly high-energy neutrinos, though not as high as what KM3NeT observed, have been detected by the IceCube Observatory — a neutrino detector embedded deep in the ice at the South Pole. IceCube has detected about half a dozen such neutrinos, whose unusually high energies have also eluded explanation. Whatever their source, the IceCube observations enable scientists to work out a plausible rate at which neutrinos of those energies typically hit Earth. If this rate were correct, however, it would be extremely unlikely to have seen the ultra-high-energy neutrino that KM3NeT recently detected. The two detectors’ discoveries, then, seemed to be what scientists call “in tension.”
Kaiser and Klipfel, who had been working on a separate project involving primordial black holes, wondered: Could a PBH have produced both the KM3NeT neutrino and the handful of IceCube neutrinos, under conditions in which PBHs comprise most of the dark matter in the galaxy? If they could show a chance existed, it would raise an even more exciting possibility — that both observatories observed not only high-energy neutrinos but also the remnants of Hawking radiation.
“Our best chance”
The first step the scientists took in their theoretical analysis was to calculate how many particles would be emitted by an exploding black hole. All black holes should slowly radiate over time. The larger a black hole, the colder it is, and the lower-energy particles it emits as it slowly evaporates. Thus, any particles that are emitted as Hawking radiation from heavy stellar-mass black holes would be near impossible to detect. By the same token, however, much smaller primordial black holes would be very hot and emit high-energy particles in a process that accelerates the closer the black hole gets to disappearing entirely.
“We don’t have any hope of detecting Hawking radiation from astrophysical black holes,” Klipfel says. “So if we ever want to see it, the smallest primordial black holes are our best chance.”
The researchers calculated the number and energies of particles that a black hole should emit, given its temperature and shrinking mass. In its final nanosecond, they estimate that once a black hole is smaller than an atom, it should emit a final burst of particles, including about 1020 neutrinos, or about a sextillion of the particles, with energies of about 100 peta-electron-volts (around the energy that KM3NeT observed).
They used this result to calculate the number of PBH explosions that would have to occur in a galaxy in order to explain the reported IceCube results. They found that, in our region of the Milky Way galaxy, about 1,000 primordial black holes should be exploding per cubic parsec per year. (A parsec is a unit of distance equal to about 3 light years, which is more than 10 trillion kilometers.)
They then calculated the distance at which one such explosion in the Milky Way could have occurred, such that just a handful of the high-energy neutrinos could have reached Earth and produced the recent KM3NeT event. They find that a PBH would have to explode relatively close to our solar system — at a distance about 2,000 times further than the distance between the Earth and our sun.
The particles emitted from such a nearby explosion would radiate in all directions. However, the team found there is a small, 8 percent chance that an explosion can happen close enough to the solar system, once every 14 years, such that enough ultra-high-energy neutrinos hit the Earth.
“An 8 percent chance is not terribly high, but it’s well within the range for which we should take such chances seriously — all the more so because so far, no other explanation has been found that can account for both the unexplained very-high-energy neutrinos and the even more surprising ultra-high-energy neutrino event,” Kaiser says.
The team’s scenario seems to hold up, at least in theory. To confirm their idea will require many more detections of particles, including neutrinos at “insanely high energies.” Then, scientists can build up better statistics regarding such rare events.
“In that case, we could use all of our combined experience and instrumentation, to try to measure still-hypothetical Hawking radiation,” Kaiser says. “That would provide the first-of-its-kind evidence for one of the pillars of our understanding of black holes — and could account for these otherwise anomalous high-energy neutrino events as well. That’s a very exciting prospect!”
In tandem, other efforts to detect nearby PBHs could further bolster the hypothesis that these unusual objects make up most or all of the dark matter.
This work was supported, in part, by the National Science Foundation, MIT’s Center for Theoretical Physics – A Leinweber Institute, and the U.S. Department of Energy.
###
Written by Jennifer Chu, MIT News
Paper: “Ultra-High-Energy Neutrinos from Primordial Black Holes”
https://journals.aps.org/prl/abstract/10.1103/vnm4-7wdc
Journal
Physical Review Letters
Article Title
“Ultra-High-Energy Neutrinos from Primordial Black Holes”
September 19, 2025
By DoW News
By U.S. Space Command
U.S. Space Command and United Kingdom Space Command conducted their first coordinated satellite maneuver from Sept. 4 to 12, demonstrating the alliance’s readiness to conduct dynamic, responsible and integrated space operations.
The Rendezvous Proximity Operation, delivered under Multinational Force – Operation Olympic Defender, repositioned a U.S. satellite to examine a U.K. satellite and assure our ally of its nominal operation in orbit.
“This operation was a first of its kind for U.K. Space Command and represents a significant increase in operational capability,” said Royal Air Force Maj. Gen. Paul Tedman, U.K. Space Command commander. “Expertly executed with U.S. Space Command, I could not be more pleased or proud of the rapid progress we are making with our allies in Multinational Force – Operation Olympic Defender. We are now, with our allies, conducting advanced orbital operations to protect and defend our shared national and military interests in space.”
The long-standing interoperability between the U.K. and the U.S. extends into space through continuous security cooperation, information sharing and exercises. The U.K. was also among the first nations to join the Spacecom-led coalition alongside the U.S., with the purpose of unifying combined space operations, should they ever be needed in conflict. The coordinated on-orbit maneuver marks the continued progress in maturing the Olympic Defender cooperation framework.
“This coordinated maneuver between two allies validated the interoperability that’s foundational to our collective defense,” said Space Force Lt. Gen. Douglas Schiess, commander of U.S. Space Forces-Space and Spacecom’s Combined Joint Force Space Component Command. “The confirmation of the [Multinational Force]’s combined military might on-orbit delivers a credible deterrent in the increasingly contested space domain.”
Schiess said space is a team sport, and no nation can accomplish all that is required to meet its objectives there alone. Cooperation between the U.S. and the U.K. provides a more comprehensive understanding of the congested and complex space environment, as well as opportunities to maintain readiness for major engagements, and ensures safe and responsible space operations.
“The success of this multidomain operation represents the warfighting advantage realized by employing our capabilities and expertise as one unified team,” said Space Force Gen. Stephen Whiting, commander of Spacecom and Olympic Defender. “Though our opponents may attempt to replicate the value of such cooperation, our partnerships are uniquely defined by not only the mutual goal of deterring aggression but a shared pledge to fight and win shoulder to shoulder, if necessary.”
DoW News publishes news from the US Department of War, previously known as the Defense Department.
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