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By NASA
Hubble Space Telescope Home NASA’s Hubble Finds… Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 5 Min Read NASA’s Hubble Finds Sizzling Details About Young Star FU Orionis
An artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. Credits:
NASA-JPL, Caltech In 1936, astronomers saw a puzzling event in the constellation Orion: the young star FU Orionis (FU Ori) became a hundred times brighter in a matter of months. At its peak, FU Ori was intrinsically 100 times brighter than our Sun. Unlike an exploding star though, it has declined in luminosity only languidly since then.
Now, a team of astronomers has wielded NASA’s Hubble Space Telescope‘s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. They find that the inner disk touching the star is extraordinarily hot — which challenges conventional wisdom.
The observations were made with the telescope’s COS (Cosmic Origins Spectrograph) and STIS (Space Telescope Imaging Spectrograph) instruments. The data includes the first far-ultraviolet and new near-ultraviolet spectra of FU Ori.
“We were hoping to validate the hottest part of the accretion disk model, to determine its maximum temperature, by measuring closer to the inner edge of the accretion disk than ever before,” said Lynne Hillenbrand of Caltech in Pasadena, California, and a co-author of the paper. “I think there was some hope that we would see something extra, like the interface between the star and its disk, but we were certainly not expecting it. The fact we saw so much extra — it was much brighter in the ultraviolet than we predicted — that was the big surprise.”
A Better Understanding of Stellar Accretion
Originally deemed to be a unique case among stars, FU Ori exemplifies a class of young, eruptive stars that undergo dramatic changes in brightness. These objects are a subset of classical T Tauri stars, which are newly forming stars that are building up by accreting material from their disk and the surrounding nebula. In classical T Tauri stars, the disk does not touch the star directly because it is restricted by the outward pressure of the star’s magnetic field.
The accretion disks around FU Ori objects, however, are susceptible to instabilities due to their enormous mass relative to the central star, interactions with a binary companion, or infalling material. Such instability means the mass accretion rate can change dramatically. The increased pace disrupts the delicate balance between the stellar magnetic field and the inner edge of the disk, leading to material moving closer in and eventually touching the star’s surface.
This is an artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. A team of astronomers has used the Hubble Space Telescope’s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. They found that the inner disk, touching the star, is much hotter than expected—16,000 kelvins—nearly three times our Sun’s surface temperature. That sizzling temperature is nearly twice as hot as previously believed. NASA-JPL, Caltech
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The enhanced infall rate and proximity of the accretion disk to the star make FU Ori objects much brighter than a typical T Tauri star. In fact, during an outburst, the star itself is outshined by the disk. Furthermore, the disk material is orbiting rapidly as it approaches the star, much faster than the rotation rate of the stellar surface. This means that there should be a region where the disk impacts the star and the material slows down and heats up significantly.
“The Hubble data indicates a much hotter impact region than models have previously predicted,” said Adolfo Carvalho of Caltech and lead author of the study. “In FU Ori, the temperature is 16,000 kelvins [nearly three times our Sun’s surface temperature]. That sizzling temperature is almost twice the amount prior models have calculated. It challenges and encourages us to think of how such a jump in temperature can be explained.”
To address the significant difference in temperature between past models and the recent Hubble observations, the team offers a revised interpretation of the geometry within FU Ori’s inner region: The accretion disk’s material approaches the star and once it reaches the stellar surface, a hot shock is produced, which emits a lot of ultraviolet light.
Planet Survival Around FU Ori
Understanding the mechanisms of FU Ori’s rapid accretion process relates more broadly to ideas of planet formation and survival.
“Our revised model based on the Hubble data is not strictly bad news for planet evolution, it’s sort of a mixed bag,” explained Carvalho. “If the planet is far out in the disk as it’s forming, outbursts from an FU Ori object should influence what kind of chemicals the planet will ultimately inherit. But if a forming planet is very close to the star, then it’s a slightly different story. Within a couple outbursts, any planets that are forming very close to the star can rapidly move inward and eventually merge with it. You could lose, or at least completely fry, rocky planets forming close to such a star.”
Additional work with the Hubble UV observations is in progress. The team is carefully analyzing the various spectral emission lines from multiple elements present in the COS spectrum. This should provide further clues on FU Ori’s environment, such as the kinematics of inflowing and outflowing gas within the inner region.
“A lot of these young stars are spectroscopically very rich at far ultraviolet wavelengths,” reflected Hillenbrand. “A combination of Hubble, its size and wavelength coverage, as well as FU Ori’s fortunate circumstances, let us see further down into the engine of this fascinating star-type than ever before.”
These findings have been published in The Astrophysical Journal Letters.
The observations were taken as part of General Observer program 17176.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, 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.
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Media Contacts:
Claire Andreoli (claire.andreoli@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Abigail Major, Ray Villard
Space Telescope Science Institute, Baltimore, MD
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Last Updated Nov 21, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
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Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
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By NASA
5 Min Read Making Mars’ Moons: Supercomputers Offer ‘Disruptive’ New Explanation
A NASA study using a series of supercomputer simulations reveals a potential new solution to a longstanding Martian mystery: How did Mars get its moons? The first step, the findings say, may have involved the destruction of an asteroid.
The research team, led by Jacob Kegerreis, a postdoctoral research scientist at NASA’s Ames Research Center in California’s Silicon Valley, found that an asteroid passing near Mars could have been disrupted – a nice way of saying “ripped apart” – by the Red Planet’s strong gravitational pull.
The team’s simulations show the resulting rocky fragments being strewn into a variety of orbits around Mars. More than half the fragments would have escaped the Mars system, but others would’ve stayed in orbit. Tugged by the gravity of both Mars and the Sun, in the simulations some of the remaining asteroid pieces are set on paths to collide with one another, every encounter further grinding them down and spreading more debris.
Many collisions later, smaller chunks and debris from the former asteroid could have settled into a disk encircling the planet. Over time, some of this material is likely to have clumped together, possibly forming Mars’ two small moons, Phobos and Deimos.
To assess whether this was a realistic chain of events, the research team explored hundreds of different close encounter simulations, varying the asteroid’s size, spin, speed, and distance at its closest approach to the planet. The team used their high-performance, open-source computing code, called SWIFT, and the advanced computing systems at Durham University in the United Kingdom to study in detail both the initial disruption and, using another code, the subsequent orbits of the debris.
In a paper published Nov. 20 in the journal Icarus, the researchers report that, in many of the scenarios, enough asteroid fragments survive and collide in orbit to serve as raw material to form the moons.
“It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s,” said Kegerreis. “Furthermore, this new model makes different predictions about the moons’ properties that can be tested against the standard ideas for this key event in Mars’ history.”
Two hypotheses for the formation of the Martian moons have led the pack. One proposes that passing asteroids were captured whole by Mars’ gravity, which could explain the moons’ somewhat asteroid-like appearance. The other says that a giant impact on the planet blasted out enough material – a mix of Mars and impactor debris – to form a disk and, ultimately, the moons. Scientists believe a similar process formed Earth’s Moon.
The latter explanation better accounts for the paths the moons travel today – in near-circular orbits that closely align with Mars’ equator. However, a giant impact ejects material into a disk that, mostly, stays close to the planet. And Mars’ moons, especially Deimos, sit quite far away from the planet and probably formed out there, too.
“Our idea allows for a more efficient distribution of moon-making material to the outer regions of the disk,” said Jack Lissauer, a research scientist at Ames and co-author on the paper. “That means a much smaller ‘parent’ asteroid could still deliver enough material to send the moons’ building blocks to the right place.”
It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s.
Jacob Kegerreis
Postdoctoral research scientist at NASA’s Ames Research Center
Testing different ideas for the formation of Mars’ moons is the primary goal of the upcoming Martian Moons eXploration (MMX) sample return mission led by JAXA (Japan Aerospace Exploration Agency). The spacecraft will survey both moons to determine their origin and collect samples of Phobos to bring to Earth for study. A NASA instrument on board, called MEGANE – short for Mars-moon Exploration with GAmma rays and Neutrons – will identify the chemical elements Phobos is made of and help select sites for the sample collection. Some of the samples will be collected by a pneumatic sampler also provided by NASA as a technology demonstration contribution to the mission. Understanding what the moons are made of is one clue that could help distinguish between the moons having an asteroid origin or a planet-plus-impactor source.
Before scientists can get their hands on a piece of Phobos to analyze, Kegerreis and his team will pick up where they left off demonstrating the formation of a disk that has enough material to make Phobos and Deimos.
“Next, we hope to build on this proof-of-concept project to simulate and study in greater detail the full timeline of formation,” said Vincent Eke, associate professor at the Institute for Computational Cosmology at Durham University and a co-author on the paper. “This will allow us to examine the structure of the disk itself and make more detailed predictions for what the MMX mission could find.”
For Kegerreis, this work is exciting because it also expands our understanding of how moons might be born – even if it turns out that Mars’ own formed by a different route. The simulations offer a fascinating exploration, he says, of the possible outcomes of encounters between objects like asteroids and planets. These events were common in the early solar system, and simulations could help researchers reconstruct the story of how our cosmic backyard evolved.
This research is a collaborative effort between Ames and Durham University, supported by the Institute for Computational Cosmology’s Planetary Giant Impact Research group. The simulations used were run using the open-source SWIFT code, carried out on the DiRAC (Distributed Research Utilizing Advanced Computing) Memory Intensive service (“COSMA”), hosted by Durham University on behalf of the DiRAC High-Performance Computing facility.
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Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.
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Last Updated Nov 20, 2024 Related Terms
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Zoom into Solar Orbiter's four new Sun images, assembled from high-resolution observations by the spacecraft's PHI and EUI instruments made on 22 March 2023. The PHI images are the highest-resolution full views of the Sun's visible surface to date, including maps of the Sun's messy magnetic field and movement on the surface. These can be compared to the new EUI image, which reveals the Sun's glowing outer atmosphere, or corona.
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Abigail Reigner, a systems engineer at NASA’s Glenn Research Center in Cleveland, supports the agency’s research in electrified aircraft propulsion to enable more sustainable air travel. Behind her is a 25% scale model of NASA’s SUbsonic Single Aft eNgine (SUSAN) Electrofan aircraft concept used to test and demonstrate hybrid electric propulsion systems for emission reductions and performance boosts in future commercial aircraft.
Credit: NASA/Sara Lowthian-Hanna Growing up outside of Philadelphia, Abigail Reigner spent most of her childhood miles away from where her family called home, and where there was little trace of her Native American tribe and culture.
Belonging to the Comanche Nation that resides in Lawton, Oklahoma, Reigner’s parents made every effort to keep her connected to her Indigenous heritage and part of a community that would later play a key role in her professional journey.
“My parents were really adamant on making sure my brother and I were still involved in the Native American traditions."
Abigail Reigner
“My parents were really adamant on making sure my brother and I were still involved in the Native American traditions,” Reigner said. “We would go down to Oklahoma often in the summertime, spending time with family and staying immersed in our culture.”
Both her parents come from a teaching background, so Reigner was surrounded by hands-on learning experiences early in life. As a school teacher, her mother would participate in local outreach events each year, talking and interacting with students. Her father, a middle school technology education teacher, taught Reigner how to use computer-aided design (CAD) and helped introduce her to the world of engineering at a young age.
These unique experiences helped spark Reigner’s curiosity for learning about science, technology, engineering, and math (STEM) and connecting with others in her community who shared these interests. Reigner says she never takes her upbringing for granted.
“I feel pretty lucky to have grown up with so many educational opportunities, and I try to use them as a way to give back to my community,” Reigner said.
After participating in various engineering and robotics classes in high school and realizing a career in STEM was the right fit for her, Reigner went on to attend the Rochester Institute of Technology in New York where she earned bachelor’s and master’s degrees in mechanical engineering.
During her time there, she joined the American Indian Science and Engineering Society (AISES) where she got the unique opportunity to connect with other Indigenous students and mentors in STEM fields and gain leadership experience on projects that eventually set her up for internship opportunities at NASA.
“The opportunities I got through AISES led me to get an internship at NASA’s Jet Propulsion Laboratory during the summer of 2021, and then an eight-month co-op the following year working in the center’s materials science division,” Reigner said.
Through AISES, Reigner also met Joseph Connolly, an aerospace engineer at NASA’s Glenn Research Center in Cleveland who was looking to recruit Indigenous students for full-time positions in the agency. Upon graduating from college, Reigner joined NASA Glenn as an engineer in the summer of 2024.
Abigail Reigner (top far left) and Joseph Connolly (middle far right) pose with NASA employees while staffing a booth at an American Indian Science and Engineering Society (AISES) conference to help recruit Indigenous students to the agency. Credit: Abigail Reigner Today, Reigner works as a systems engineer supporting NASA Glenn’s efforts to test and demonstrate electrified aircraft propulsion technologies for future commercial aircraft as part of the agency’s mission to make air travel more sustainable.
One of the projects she works on is NASA’s Electrified Powertrain Flight Demonstration (EPFD), where she supports risk-reduction testing that enables the project to explore the feasibility of hybrid electric propulsion in reducing emissions and improving efficiency in future aircraft.
“It’s always good to know that you’re doing something that is furthering the benefit of humanity,” Reigner said. “Seeing that unity across NASA centers and knowing that you are a part of something that is accelerating technology for the future is very cool.”
“I really feel like the reason I am here at NASA is because of the success of not just the Native American support group here at Glenn, but also Natives across the agency.”
Abigail Reigner
The growing community of Native Americans at NASA Glenn has fostered several initiatives over the years that have helped recruit, inspire, and retain Indigenous employees.
Leveraging some of the agency’s diversity programs that provide educational STEM opportunities for underrepresented communities, the Native Americans at NASA group has encouraged more students with Indigenous backgrounds to get involved in technical projects while developing the skills needed to excel in STEM fields.
“The Native American support group at NASA has been around since the mid-to-late 1980s and was actually one of the first Native American employee resources groups at the agency,” Connolly said. “Through this, we’ve been able to connect a number of Native employees with senior leaders across NASA and establish more agencywide recruitment efforts and initiatives for Native Americans.”
These initiatives range from support through NASA’s Minority University Research and Education Project (MUREP) to help recruit more Indigenous students, to encouraging participation in hands-on learning experiences through projects such as NASA’s University Leadership Initiative (ULI) and the agency’s involvement in the First Nations Launch competition, which helps provide students with opportunities to conduct research while developing engineering and team-building skills.
The efforts of the Native American community at NASA Glenn and across the agency have been successful in not only creating a direct pipeline for Indigenous students into the NASA workforce, but also allowing them to feel seen and represented in the agency, says Connolly.
For Reigner, having this community and resource group at NASA to help guide and support her through her journey has been crucial to her success and important for the future of diversity within the agency.
“I really feel like the reason I am here at NASA is because of the success of not just the Native American support group here at Glenn, but also Natives across the agency,” Reigner said. Without their support and initiatives to recruit and retain students, I wouldn’t be here today.”
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By NASA
Clayton P. Turner, associate administrator for Space Technology Mission DirectorateCredit: NASA Clayton P. Turner will serve as the associate administrator of the Space Technology Mission Directorate (STMD) at the agency’s headquarters in Washington, NASA Administrator Bill Nelson announced Monday. His appointment is effective immediately.
Turner has served as the acting associate administrator of STMD since July. In this role, Turner will continue to oversee executive leadership, strategic planning, and overall management of all technology maturation and demonstration programs executed from the directorate enabling critical space focused technologies that deliver today and help create tomorrow.
“Under Turner’s skilled and steady hand, the Space Technology Mission Directorate will continue to do what it does best: help NASA push the boundaries of what’s possible and drive American leadership in space,” said NASA Administrator Bill Nelson. “I look forward to what STMD will achieve under Turner’s direction.”
As NASA embarks on the next era of space exploration, STMD leverages partnerships to advance technologies and test new capabilities helping the agency develop a sustainable presence on the Moon and beyond. As associate administrator of STMD, Turner will plan, coordinate, and evaluate the mission directorate’s full range of programs and activities, including budget formulation and execution, as well as represent the programs to officials within and outside the agency.
Previously, Turner served as NASA Langley Research Center Director since September 2019 and has been with the agency for more than 30 years. He has held several roles at NASA Langley, including engineering director, associate center director, and deputy center director. Throughout his NASA career, he has worked on many projects for the agency, including: the Earth Science Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation Project; the materials technology development Gas Permeable Polymer Materials Project; the Space Shuttle Program’s Return to Flight work; the flight test of the Ares 1-X rocket; the flight test of the Orion Launch Abort System; and the entry, descent, and landing segment of the Mars Science Laboratory.
In recognition of his commitment to the agency and engineering, Turner has received many prestigious awards, such as the NASA Distinguished Service Medal, the NASA Outstanding Leadership Medal, the NASA Exceptional Engineering Achievement Medal. He is also an Associate Fellow of the American Institute of Aeronautics and Astronautics (AIAA) and a Board of Trustees member of his alma mater, Rochester Institute of Technology.
NASA Glenn Research Center Deputy Director, Dawn Schaible, became acting Langley Center Director in July and will continue to serve in this role. At NASA Langley, Schaible leads a skilled group of more than 3,000 civil servant and contractor scientists, researchers, engineers, and support staff, who work to advance aviation, expand understanding of Earth’s atmosphere, and develop technology for space exploration.
For more about Turner’s experience, visit his full biography online at:
https://go.nasa.gov/48UmkmS
-end-
Meira Bernstein / Jasmine Hopkins
Headquarters, Washington
202-358-1600
meira.b.bernstein@nasa.gov / jasmine.s.hopkins@nasa.gov
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Last Updated Nov 18, 2024 LocationNASA Headquarters Related Terms
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