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NASA Selects Proposals to Study Stellar Explosions, Galaxies, Stars
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By Space Force
In partnership with the Air Force Research Laboratory, the United States Space Force is currently accepting proposals for USSF University Consortium/Space Strategic Technology Institute 4, focused on Advanced Remote Sensing.
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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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Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Exploring the Birth of Stars
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Hubble Focus: The Lives of Stars
This e-book highlights the mission’s recent discoveries and observations related to the birth, evolution, and death of stars.
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By NASA
On Nov. 6, 2024, NASA Night brought cosmic excitement to the Toyota Center, where Johnson Space Center employees joined 16,208 fans who interacted with NASA as they watched the Houston Rockets claim victory over the San Antonio Spurs.
Energy soared as International Space Station Program Manager Dana Weigel stepped up to take the first shot.
International Space Station Program Manager Dana Weigel takes the first shot on Nov. 6, 2024, as the Houston Rockets go up against the San Antonio Spurs at Toyota Center.NASA/Helen Arase Vargas The ceremonial first shot also gave back to the community, with Rockets owner Tilman Fertitta donating $1,000 to the Clutch City Foundation to support underserved youth through education, sports, and disaster relief.
Throughout the game, Johnson employees kept the crowd engaged with NASA trivia, creating a “launch countdown” energy that had fans cheering. The arena lit up as Adam Savage narrated a video showcasing the International Space Station’s groundbreaking contributions to science. From unlocking discoveries impossible on Earth to testing critical technologies for our return to the Moon, the orbiting laboratory plays a vital role in advancing medical and social breakthroughs that enhance life on our planet.
The Artemis II crew also appeared on the jumbotron, reminding everyone of NASA’s mission to establish a long-term presence on the Moon for scientific discovery, economic benefits, and to inspire a new generation of explorers.
Dana Weigel, center, shows off a Rockets jersey on the court with Rockets mascot Clutch, left, and NASA mascot Cosmo.NASA/Helen Arase Vargas In the Sky Court area of the stadium concourse, Johnson volunteers held “mission control” with an interactive exhibit that drew fans in like a gravitational pull. From exploring a Space Launch System model and handling a spacesuit helmet and glove to touching a 3.4-billion-year-old Moon rock collected during Apollo 17, NASA’s booth offered attendees a glimpse into space exploration.
Visitors had the chance to ask questions and bring home mission pins, stickers, and hands-on activities, provided by the International Space Station Program and the Artemis campaign. Seventy-five “Lucky Row” fans also received bags filled with NASA outreach materials, courtesy of the Johnson Public Engagement team.
NASA’s Johnson Space Center volunteers connect with fans at the game through an interactive exhibit.NASA The Orion Flight Simulator, with its realistic switches and displays, provided an immersive experience that allowed fans to dock the Orion spacecraft to humanity’s first lunar space station, Gateway.
More than 600 fans eagerly lined up to experience NASA’s mobile exhibit trailer in the Toyota Center parking lot—drawing lines as long as those at the box office.
Fans engage with the Orion Flight Simulator at NASA’s booth. NASA/Helen Arase Vargas Fans also tested their skills with a crew assembly activity focused on science, technology, engineering, and mathematics, simulating the challenges astronauts face in orbit. NASA’s inflatable mascot, Cosmo, joined the action on the court, posing for photos and adding galactic fun to events like the T-shirt giveaway.
The Houston Rockets mascot Clutch and NASA mascot Cosmo team up on the court at Toyota Center in Houston.NASA/Helen Arase Vargas NASA’s presence brought together the excitement of sports with the wonder of space exploration, inspiring fans to keep shooting for the stars.
View more images from the event below.
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By NASA
5 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
A prototype of a robot designed to explore subsurface oceans of icy moons is reflected in the water’s surface during a pool test at Caltech in September. Conducted by NASA’s Jet Propulsion Laboratory, the testing showed the feasibility of a mission concept for a swarm of mini swimming robots.NASA/JPL-Caltech In a competition swimming pool, engineers tested prototypes for a futuristic mission concept: a swarm of underwater robots that could look for signs of life on ocean worlds.
When NASA’s Europa Clipper reaches its destination in 2030, the spacecraft will prepare to aim an array of powerful science instruments toward Jupiter’s moon Europa during 49 flybys, looking for signs that the ocean beneath the moon’s icy crust could sustain life. While the spacecraft, which launched Oct. 14, carries the most advanced science hardware NASA has ever sent to the outer solar system, teams are already developing the next generation of robotic concepts that could potentially plunge into the watery depths of Europa and other ocean worlds, taking the science even further.
This is where an ocean-exploration mission concept called SWIM comes in. Short for Sensing With Independent Micro-swimmers, the project envisions a swarm of dozens of self-propelled, cellphone-size swimming robots that, once delivered to a subsurface ocean by an ice-melting cryobot, would zoom off, looking for chemical and temperature signals that could indicate life.
Dive into underwater robotics testing with NASA’s futuristic SWIM (Sensing With Independent Micro-swimmers) concept for a swarm of miniature robots to explore subsurface oceans on icy worlds, and see a JPL team testing a prototype at a pool at Caltech in Pasadena, California, in September 2024. NASA/JPL-Caltech “People might ask, why is NASA developing an underwater robot for space exploration? It’s because there are places we want to go in the solar system to look for life, and we think life needs water. So we need robots that can explore those environments — autonomously, hundreds of millions of miles from home,” said Ethan Schaler, principal investigator for SWIM at NASA’s Jet Propulsion Laboratory in Southern California.
Under development at JPL, a series of prototypes for the SWIM concept recently braved the waters of a 25-yard (23-meter) competition swimming pool at Caltech in Pasadena for testing. The results were encouraging.
SWIM Practice
The SWIM team’s latest iteration is a 3D-printed plastic prototype that relies on low-cost, commercially made motors and electronics. Pushed along by two propellers, with four flaps for steering, the prototype demonstrated controlled maneuvering, the ability to stay on and correct its course, and a back-and-forth “lawnmower” exploration pattern. It managed all of this autonomously, without the team’s direct intervention. The robot even spelled out “J-P-L.”
Just in case the robot needed rescuing, it was attached to a fishing line, and an engineer toting a fishing rod trotted alongside the pool during each test. Nearby, a colleague reviewed the robot’s actions and sensor data on a laptop. The team completed more than 20 rounds of testing various prototypes at the pool and in a pair of tanks at JPL.
“It’s awesome to build a robot from scratch and see it successfully operate in a relevant environment,” Schaler said. “Underwater robots in general are very hard, and this is just the first in a series of designs we’d have to work through to prepare for a trip to an ocean world. But it’s proof that we can build these robots with the necessary capabilities and begin to understand what challenges they would face on a subsurface mission.”
Swarm Science
A model of the final envisioned SWIM robot, right, sits beside a capsule holding an ocean-composition sensor. The sensor was tested on an Alaskan glacier in July 2023 through a JPL-led project called ORCAA (Ocean Worlds Reconnaissance and Characterization of Astrobiological Analogs). The wedge-shaped prototype used in most of the pool tests was about 16.5 inches (42 centimeters) long, weighing 5 pounds (2.3 kilograms). As conceived for spaceflight, the robots would have dimensions about three times smaller — tiny compared to existing remotely operated and autonomous underwater scientific vehicles. The palm-size swimmers would feature miniaturized, purpose-built parts and employ a novel wireless underwater acoustic communication system for transmitting data and triangulating their positions.
Digital versions of these little robots got their own test, not in a pool but in a computer simulation. In an environment with the same pressure and gravity they would likely encounter on Europa, a virtual swarm of 5-inch-long (12-centimeter-long) robots repeatedly went looking for potential signs of life. The computer simulations helped determine the limits of the robots’ abilities to collect science data in an unknown environment, and they led to the development of algorithms that would enable the swarm to explore more efficiently.
The simulations also helped the team better understand how to maximize science return while accounting for tradeoffs between battery life (up to two hours), the volume of water the swimmers could explore (about 3 million cubic feet, or 86,000 cubic meters), and the number of robots in a single swarm (a dozen, sent in four to five waves).
In addition, a team of collaborators at Georgia Tech in Atlanta fabricated and tested an ocean composition sensor that would enable each robot to simultaneously measure temperature, pressure, acidity or alkalinity, conductivity, and chemical makeup. Just a few millimeters square, the chip is the first to combine all those sensors in one tiny package.
Of course, such an advanced concept would require several more years of work, among other things, to be ready for a possible future flight mission to an icy moon. In the meantime, Schaler imagines SWIM robots potentially being further developed to do science work right here at home: supporting oceanographic research or taking critical measurements underneath polar ice.
More About SWIM
Caltech manages JPL for NASA. JPL’s SWIM project was supported by Phase I and II funding from NASA’s Innovative Advanced Concepts (NIAC) program under the agency’s Space Technology Mission Directorate. The program nurtures visionary ideas for space exploration and aerospace by funding early-stage studies to evaluate technologies that could transform future NASA missions. Researchers across U.S. government, industry, and academia can submit proposals.
How the SWIM concept was developed Learn about underwater robots for Antarctic climate science See NASA’s network of ready-to-roll mini-Moon rovers News Media Contact
Melissa Pamer
Jet Propulsion Laboratory, Pasadena, Calif.
626-314-4928
melissa.pamer@jpl.nasa.gov
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Last Updated Nov 20, 2024 Related Terms
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By NASA
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NASA’s Swift Reaches 20th Anniversary in Improved Pointing Mode
After two decades in space, NASA’s Neil Gehrels Swift Observatory is performing better than ever thanks to a new operational strategy implemented earlier this year. The spacecraft has made great scientific strides in the years since scientists dreamed up a new way to explore gamma-ray bursts, the most powerful explosions in the universe.
“The idea for Swift was born during a meeting in a hotel basement in Estes Park, Colorado, in the middle of a conference,” said John Nousek, the Swift mission director at Pennsylvania State University in State College. “A bunch of astrophysicists got together to brainstorm a mission that could help us solve the problem of gamma-ray bursts, which were a very big mystery at the time.”
Watch to learn how NASA’s Neil Gehrels Swift Observatory got its name.
NASA’s Goddard Space Flight Center Gamma-ray bursts occur all over the sky without warning, with about one a day detected on average. Astronomers generally divide these bursts into two categories. Long bursts produce an initial pulse of gamma rays for two seconds or more and occur when the cores of massive stars collapse to form black holes. Short bursts last less than two seconds and are caused by the mergers of dense objects like neutron stars.
But in 1997, at the time of that basement meeting, the science community disagreed over the origin models for these events. Astronomers needed a satellite that could move quickly to locate them and move to point additional instruments at their positions.
What developed was Swift, which launched Nov. 20, 2004, from Complex 17A at what is now Cape Canaveral Space Force Station in Florida. Originally called the Swift Observatory for its ability to quickly point at cosmic events, the mission team renamed the spacecraft in 2018 after its first principal investigator Neil Gehrels.
Swift uses several methods for orienting and stabilizing itself in space to study gamma-ray bursts.
Sensors that detect the Sun’s location and the direction of Earth’s magnetic field provide the spacecraft with a general sense of its location. Then, a device called a star tracker looks at stars and tells the spacecraft how to maneuver to keep the observatory precisely pointed at the same position during long observations.
Swift uses three spinning gyroscopes, or gyros, to carry out those moves along three axes. The gyros were designed to align at right angles to each other, but once in orbit the mission team discovered they were slightly misaligned. The flight operations team developed a strategy where one of the gyros worked to correct the misalignment while the other two pointed Swift to achieve its science goals.
The team wanted to be ready in case one of the gyros failed, however, so in 2009 they developed a plan to operate Swift using just two.
Swift orbits above Earth in this artist’s concept. NASA’s Goddard Space Flight Center Conceptual Image Lab Any change to the way a telescope operates once in space carries risk, however. Since Swift was working well, the team sat on their plan for 15 years.
Then, in July 2023, one of Swift’s gyros began working improperly. Because the telescope couldn’t hold its pointing position accurately, observations got progressively blurrier until the gyro failed entirely in March 2024.
“Because we already had the shift to two gyros planned out, we were able to quickly and thoroughly test the procedure here on the ground before implementing it on the spacecraft,” said Mark Hilliard, Swift’s flight operations team lead at Omitron, Inc. and Penn State. “Actually, scientists have commented that the accuracy of Swift’s pointing is now better than it was since launch, which is really encouraging.”
For the last 20 years, Swift has contributed to groundbreaking results — not only for gamma-ray bursts but also for black holes, stars, comets, and other cosmic objects.
“After all this time, Swift remains a crucial part of NASA’s fleet,” said S. Bradley Cenko, Swift’s principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The satellite’s abilities have helped pioneer a new era of astrophysics called multimessenger astronomy, which is giving us a more well-rounded view of how the universe works. We’re looking forward to all Swift has left to teach us.”
Swift is a key part of NASA’s strategy to look for fleeting and unpredictable changes in the sky with a variety of telescopes that use different methods of studying the cosmos.
Goddard manages the Swift mission in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico, and Northrop Grumman Space Systems in Dulles, Virginia. Other partners include the University of Leicester and Mullard Space Science Laboratory in the United Kingdom, Brera Observatory in Italy, and the Italian Space Agency.
Download high-resolution images on NASA’s Scientific Visualization Studio
By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Nov 20, 2024 Editor Jeanette Kazmierczak Location Goddard Space Flight Center Related Terms
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