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The Young Professional Satellite - From Theory to Reality (episode 2)
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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
Astrophysics Astrophysics Division Goddard Space Flight Center Hubble Space Telescope Stars Keep Exploring Discover More Topics From Hubble
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
Exploring the Birth of Stars
Hubble’s Night Sky Challenge
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 European Space Agency
Video: 00:06:45 Smile is the Solar wind Magnetosphere Ionosphere Link Explorer, a brand-new space mission currently in the making. It will study space weather and the interaction between the solar wind and Earth’s environment.
Unique about Smile is that it will take the first X-ray images and videos of the solar wind slamming into Earth’s protective magnetic bubble, and its complementary ultraviolet images will provide the longest-ever continuous look at the northern lights.
In this first of several short videos, David Agnolon (Smile Project Manager) and Philippe Escoubet (Smile Project Scientist) talk about the why and the how of Smile. You’ll see scenes of the building and testing of the spacecraft’s payload module by Airbus in Madrid, including the installation of one of the European instruments, the Soft X-ray Imager from the University of Leicester.
Smile is a 50–50 collaboration between the European Space Agency (ESA) and the Chinese Academy of Sciences (CAS). ESA provides the payload module of the spacecraft, which carries three of the four science instruments, and the Vega-C rocket which will launch Smile to space. CAS provides the platform module hosting the fourth science instrument, as well as the service and propulsion modules.
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By NASA
MuSat2 at Vandenberg Air Force Base, prior to launch. MuSat2 leverages a dual-frequency science antenna developed with support from NASA to measure phenomena such as ocean wind speed. Muon Space A science antenna developed with support from NASA’s Earth Science Technology Office (ESTO) is now in low-Earth orbit aboard MuSat2, a commercial remote-sensing satellite flown by the aerospace company Muon Space. The dual-frequency science antenna was originally developed as part of the Next Generation GNSS Bistatic Radar Instrument (NGRx). Aboard MuSat2, it will help measure ocean surface wind speed—an essential data point for scientists trying to forecast how severe a burgeoning hurricane will become.
“We’re very interested in adopting this technology and pushing it forward, both from a technology perspective and a product perspective,” said Jonathan Dyer, CEO of Muon.
Using this antenna, MuSat2 will gather signals transmitted by navigation satellites as they scatter off Earth’s surface and back into space. By recording how those scattered navigation signals change as they interact with Earth’s surface, MuSat2 will provide meteorologists with data points they can use to study severe weather.
“We use the standard GPS signals you know—the navigation signals that work for your car and your cell phone,” explained Chris Ruf, director of the University of Michigan Space Institute and principal investigator for NGRx.
Ruf designed the entire NGRx system to be an updated version of the sensors on NASA’s Cyclone Global Navigation Satellite System (CYGNSS), another technology he developed with support from ESTO. Since 2016, data from CYGNSS has been a critical resource for people dedicated to forecasting hurricanes.
The science antenna aboard MuSat2 enables two key improvements to the original CYGNSS design. First, the antenna allows MuSat2 to gather measurements from satellites outside the U.S.-based GPS system, such as the European Space Agency’s Galileo satellites. This capability enables MuSat2 to collect more data as it orbits Earth, improving its assessments of conditions on the planet’s surface.
Second, whereas CYGNSS only collected cross-polar radar signals, the updated science antenna also collects co-polar radar signals. This additional information could provide improved information about soil moisture, sea ice, and vegetation. “There’s a whole lot of science value in looking at both polarization components scattering from the Earth’s surface. You can separate apart the effects of vegetation from the effects of surface, itself,” explained Ruf.
Hurricane Ida, as seen from the International Space Station. NASA-developed technology onboard MuSat2 will help supply the U.S. Air Force with critical data for producing reliable weather forecasts. NASA For Muon Space, this technology infusion has been helpful to the company’s business and science missions. Dallas Masters, Vice President of Muon’s Signals of Opportunity Program, explains that NASA’s investments in NGRx technology made it much easier to produce a viable commercial remote sensing satellite. According to Masters, “NGRx-derived technology allowed us to start planning a flight mission early in our company’s existence, based around a payload we knew had flight heritage.”
Dyer agrees. “The fact that ESTO proves out these measurement approaches – the technology and the instrument, the science that you can actually derive, the products from that instrument – is a huge enabler for companies like ours, because we can adopt it knowing that much of the physics risk has been retired,” he said.
Ultimately, this advanced antenna technology for measuring ocean surface wind speed will make it easier for researchers to turn raw data into actionable science products and to develop more accurate forecasts.
“Information is absolutely precious. When it comes to forecast models and trying to understand what’s about to happen, you have to have as good an idea as you can of what’s already happening in the real world,” said oceanographer Lew Gramer, an Associate Scientist with the Cooperative Institute For Marine And Atmospheric Studies and NOAA’s Hurricane Research Division.
Project Lead: Chris Ruf, University of Michigan
Sponsoring Organizations: NASA’s Earth Science Technology Office and Muon Space
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Last Updated Nov 12, 2024 Related Terms
CYGNSS (Cyclone Global Navigation Satellite System) Earth Science Earth Science Division Earth Science Technology Office Oceans Science-enabling Technology Technology Highlights Explore More
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By European Space Agency
ESA is taking a significant step towards creating a more digitally inclusive Europe through a new partnership that will bring internet access to the hardest-to-reach areas. Reliable connectivity has become essential in today's digital age, yet for many Europeans in rural villages, mountainous regions, and small islands, dependable internet access remains out of reach.
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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The NISAR mission will help researchers get a better understanding of how Earth’s surface changes over time, including in the lead-up to volcanic eruptions like the one pictured, at Mount Redoubt in southern Alaska in April 2009.R.G. McGimsey/AVO/USGS Data from NISAR will improve our understanding of such phenomena as earthquakes, volcanoes, and landslides, as well as damage to infrastructure.
We don’t always notice it, but much of Earth’s surface is in constant motion. Scientists have used satellites and ground-based instruments to track land movement associated with volcanoes, earthquakes, landslides, and other phenomena. But a new satellite from NASA and the Indian Space Research Organisation (ISRO) aims to improve what we know and, potentially, help us prepare for and recover from natural and human-caused disasters.
The NISAR (NASA-ISRO Synthetic Aperture Radar) mission will measure the motion of nearly all of the planet’s land and ice-covered surfaces twice every 12 days. The pace of NISAR’s data collection will give researchers a fuller picture of how Earth’s surface changes over time. “This kind of regular observation allows us to look at how Earth’s surface moves across nearly the entire planet,” said Cathleen Jones, NISAR applications lead at NASA’s Jet Propulsion Laboratory in Southern California.
Together with complementary measurements from other satellites and instruments, NISAR’s data will provide a more complete picture of how Earth’s surface moves horizontally and vertically. The information will be crucial to better understanding everything from the mechanics of Earth’s crust to which parts of the world are prone to earthquakes and volcanic eruptions. It could even help resolve whether sections of a levee are damaged or if a hillside is starting to move in a landslide.
The NISAR mission will measure the motion of Earth’s surface — data that can be used to monitor critical infrastructure such as airport runways, dams, and levees. NASA/JPL-Caltech What Lies Beneath
Targeting an early 2025 launch from India, the mission will be able to detect surface motions down to fractions of an inch. In addition to monitoring changes to Earth’s surface, the satellite will be able to track the motion of ice sheets, glaciers, and sea ice, and map changes to vegetation.
The source of that remarkable detail is a pair of radar instruments that operate at long wavelengths: an L-band system built by JPL and an S-band system built by ISRO. The NISAR satellite is the first to carry both. Each instrument can collect measurements day and night and see through clouds that can obstruct the view of optical instruments. The L-band instrument will also be able to penetrate dense vegetation to measure ground motion. This capability will be especially useful in areas surrounding volcanoes or faults that are obscured by vegetation.
“The NISAR satellite won’t tell us when earthquakes will happen. Instead, it will help us better understand which areas of the world are most susceptible to significant earthquakes,” said Mark Simons, the U.S. solid Earth science lead for the mission at Caltech in Pasadena, California.
Data from the satellite will give researchers insight into which parts of a fault slowly move without producing earthquakes and which sections are locked together and might suddenly slip. In relatively well-monitored areas like California, researchers can use NISAR to focus on specific regions that could produce an earthquake. But in parts of the world that aren’t as well monitored, NISAR measurements could reveal new earthquake-prone areas. And when earthquakes do occur, data from the satellite will help researchers understand what happened on the faults that ruptured.
“From the ISRO perspective, we are particularly interested in the Himalayan plate boundary,” said Sreejith K M, the ISRO solid Earth science lead for NISAR at the Space Applications Center in Ahmedabad, India. “The area has produced great magnitude earthquakes in the past, and NISAR will give us unprecedented information on the seismic hazards of the Himalaya.”
Surface motion is also important for volcano researchers, who need data collected regularly over time to detect land movements that may be precursors to an eruption. As magma shifts below Earth’s surface, the land can bulge or sink. The NISAR satellite will help provide a fuller picture for why a volcano deforms and whether that movement signals an eruption.
Finding Normal
When it comes to infrastructure such as levees, aqueducts, and dams, NISAR’s ability to provide continuous measurements over years will help to establish the usual state of the structures and surrounding land. Then, if something changes, resource managers may be able to pinpoint specific areas to examine. “Instead of going out and surveying an entire aqueduct every five years, you can target your surveys to problem areas,” said Jones.
The data could be equally valuable for showing that a dam hasn’t changed after a disaster like an earthquake. For instance, if a large earthquake struck San Francisco, liquefaction — where loosely packed or waterlogged sediment loses its stability after severe ground shaking — could pose a problem for dams and levees along the Sacramento-San Joaquin River Delta.
“There’s over a thousand miles of levees,” said Jones. “You’d need an army to go out and look at them all.” The NISAR mission would help authorities survey them from space and identify damaged areas. “Then you can save your time and only go out to inspect areas that have changed. That could save a lot of money on repairs after a disaster.”
More About NISAR
The NISAR mission is an equal collaboration between NASA and ISRO and marks the first time the two agencies have cooperated on hardware development for an Earth-observing mission. Managed for the agency by Caltech, JPL leads the U.S. component of the project and is providing the mission’s L-band SAR. NASA is also providing the radar reflector antenna, the deployable boom, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder, and payload data subsystem. The U R Rao Satellite Centre in Bengaluru, India, which leads the ISRO component of the mission, is providing the spacecraft bus, the launch vehicle, and associated launch services and satellite mission operations. The ISRO Space Applications Centre in Ahmedabad is providing the S-band SAR electronics.
To learn more about NISAR, visit:
https://nisar.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
2024-155
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Last Updated Nov 08, 2024 Related Terms
NISAR (NASA-ISRO Synthetic Aperture Radar) Earth Science Earthquakes Jet Propulsion Laboratory Natural Disasters Volcanoes Explore More
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