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By NASA
NASA/JPL-Caltech This Oct. 4, 2017, illustration shows a hypothetical uneven ring of dust orbiting KIC 8462852, also known as Boyajian’s Star or Tabby’s Star. The star has experienced unusual dips in brightness over a matter of days, as well as much subtler but longer-term dimming trends. Scientists proposed several explanations for this unexpected behavior, ranging from Tabby’s Star swallowing a planet to alien “megastructures” harvesting the star’s energy. However, a study using NASA’s Spitzer and Swift missions as well as the Belgian AstroLAB IRIS observatory suggests that the cause of the dimming over long periods is likely an uneven dust cloud moving around the star.
Learn more about this enigmatic star, named after Tabetha Boyajian, the Yale University postdoc who discovered it with the help of citizen scientists.
Image credit: NASA/JPL-Caltech
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
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A 3D simulation showing the evolution of turbulent flows in the upper layers of the Sun. The more saturated and bright reds represent the most vigorous upward or downward twisting motions. Clear areas represent areas where there is only relatively slow up-flows, with very little twisting.NASA/Irina Kitiashvili and Timothy A. Sandstrom NASA supercomputers are shedding light on what causes some of the Sun’s most complex behaviors. Using data from the suite of active Sun-watching spacecraft currently observing the star at the heart of our solar system, researchers can explore solar dynamics like never before.
The animation shows the strength of the turbulent motions of the Sun’s inner layers as materials twist into its atmosphere, resembling a roiling pot of boiling water or a flurry of schooling fish sending material bubbling up to the surface or diving it further down below.
“Our simulations use what we call a realistic approach, which means we include as much as we know to-date about solar plasma to reproduce different phenomena observed with NASA space missions,” said Irina Kitiashvili, a scientist at NASA’s Ames Research Center in California’s Silicon Valley who helped lead the study.
Using modern computational capabilities, the team was able, for the first time to reproduce the fine structures of the subsurface layer observed with NASA’s Solar Dynamics Observatory.
“Right now, we don’t have the computational capabilities to create realistic global models of the entire Sun due to the complexity,” said Kitiashvili. “Therefore, we create models of smaller areas or layers, which can show us structures of the solar surface and atmosphere – like shock waves or tornado-like features measuring only a few miles in size; that’s much finer detail than any one spacecraft can resolve.”
Scientists seek to better understand the Sun and what phenomena drive the patterns of its activity. The connection and interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate, radiation belts, auroras and many other phenomena. Space weather predictions are critical for exploration of space, supporting the spacecraft and astronauts of NASA’s Artemis campaign. Surveying this space environment is a vital part of understanding and mitigating astronaut exposure to space radiation and keeping our spacecraft and instruments safe.
This has been a big year for our special star, studded with events like the annular eclipse, a total eclipse, and the Sun reaching its solar maximum period. In December 2024, NASA’s Parker Solar Probe mission – which is helping researchers to understand space weather right at the source – will make its closest-ever approach to the Sun and beat its own record of being the closest human-made object to reach the Sun.
The Sun keeps surprising us. We are looking forward to seeing what kind of exciting events will be organized by the Sun."
Irina Kitiashvili
NASA Scientist
“The Sun keeps surprising us,” said Kitiashvili. “We are looking forward to seeing what kind of exciting events will be organized by the Sun.”
These simulations were run on the Pleaides supercomputer at the NASA Advanced Supercomputing facility at NASA Ames over several weeks of runtime, generating terabytes of data.
NASA is showcasing 29 of the agency’s computational achievements at SC24, the international supercomputing conference, Nov. 17-22, 2023, in Atlanta, Georgia. For more technical information, visit:
https://www.nas.nasa.gov/sc24
For news media: 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 21, 2024 Related Terms
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Parker Solar Probe
On a mission to “touch the Sun,” NASA’s Parker Solar Probe became the first spacecraft to fly through the corona…
Solar Storms and Flares
Solar storms and flares are eruptions from the Sun that can affect us here on Earth.
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Track the Solar Cycle with Sunspots
Participate in sunspot-counting activities using NASA telescopes or your own.
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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.
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 NASA
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The guitar shape in the “Guitar Nebula” comes from bubbles blown by particles ejected from the pulsar through a steady wind as it moves through space. A movie of Chandra (red) data taken in 2000, 2006, 2012, and 2021 has been combined with a single image in optical light from Palomar. X-rays from Chandra show a filament of energetic matter and antimatter particles, about two light-years long, blasting away from the pulsar (seen as the bright white dot). The movie shows how this filament has changed over two decades. X-ray: NASA/CXC/Stanford Univ./M. de Vries et al.; Optical full field: Palomar Obs./Caltech & inset: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare) Normally found only in heavy metal bands or certain post-apocalyptic films, a “flame-throwing guitar” has now been spotted moving through space. Astronomers have captured movies of this extreme cosmic object using NASA’s Chandra X-ray Observatory and Hubble Space Telescope.
The new movie of Chandra (red) and Palomar (blue) data helps break down what is playing out in the Guitar Nebula. X-rays from Chandra show a filament of energetic matter and antimatter particles, about two light-years or 12 trillion miles long, blasting away from the pulsar (seen as the bright white dot connected to the filament).
Astronomers have nicknamed the structure connected to the pulsar PSR B2224+65 as the “Guitar Nebula” because of its distinct resemblance to the instrument in glowing hydrogen light. The guitar shape comes from bubbles blown by particles ejected from the pulsar through a steady wind. Because the pulsar is moving from the lower right to the upper left, most of the bubbles were created in the past as the pulsar moved through a medium with variations in density.
X-ray: NASA/CXC/Stanford Univ./M. de Vries et al.; Optical: (Hubble) NASA/ESA/STScI and (Palomar) Hale Telescope/Palomar/CalTech; Image Processing: NASA/CXC/SAO/L. Frattare At the tip of the guitar is the pulsar, a rapidly rotating neutron star left behind after the collapse of a massive star. As it hurtles through space it is pumping out a flame-like filament of particles and X-ray light that astronomers have captured with Chandra.
How does space produce something so bizarre? The combination of two extremes — fast rotation and high magnetic fields of pulsars — leads to particle acceleration and high-energy radiation that creates matter and antimatter particles, as electron and positron pairs. In this situation, the usual process of converting mass into energy, famously determined by Albert Einstein’s E = mc2 equation, is reversed. Here, energy is being converted into mass to produce the particles.
Particles spiraling along magnetic field lines around the pulsar create the X-rays that Chandra detects. As the pulsar and its surrounding nebula of energetic particles have flown through space, they have collided with denser regions of gas. This allows the most energetic particles to escape the confines of the Guitar Nebula and fly to the right of the pulsar, creating the filament of X-rays. When those particles escape, they spiral around and flow along magnetic field lines in the interstellar medium, that is, the space in between stars.
The new movie shows the pulsar and the filament flying towards the upper left of the image through Chandra data taken in 2000, 2006, 2012 and 2021. The movie has the same optical image in each frame, so it does not show changes in parts of the “guitar.” A separate movie obtained with data from NASA’s Hubble Space Telescope (obtained in 1994, 2001, 2006, and 2021) shows the motion of the pulsar and the smaller structures around it.
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Hubble Space Telescope data: 1994, 2001, 2006, and 2021.X-ray: NASA/CXC/Stanford Univ./M. de Vries et al.; Optical full field: Palomar Obs./Caltech & inset: NASA/ESA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare) A study of this data has concluded that the variations that drive the formation of bubbles in the hydrogen nebula, which forms the outline of the guitar, also control changes in how many particles escape to the right of the pulsar, causing subtle brightening and fading of the X-ray filament, like a cosmic blow torch shooting from the tip of the guitar.
The structure of the filament teaches astronomers about how electrons and positrons travel through the interstellar medium. It also provides an example of how this process is injecting electrons and positrons into the interstellar medium.
A paper describing these results was published in The Astrophysical Journal and is available here.
NASA’s Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory’s Chandra X-ray Center controls science operations from Cambridge, Massachusetts, and flight operations from Burlington, Massachusetts.
Read more from NASA’s Chandra X-ray Observatory.
Learn more about the Chandra X-ray Observatory and its mission here:
https://www.nasa.gov/chandra
https://chandra.si.edu
Visual Description:
This release features two short videos and a labeled composite image, all featuring what can be described as a giant flame-throwing guitar floating in space.
In both the six second multiwavelength Guitar Nebula timelapse video and the composite image, the guitar shape appears at our lower left, with the neck of the instrument pointing toward our upper left. The guitar shape is ghostly and translucent, resembling a wispy cloud on a dark night. At the end of the neck, the guitar’s headstock comes to a sharp point that lands on a bright white dot. This dot is a pulsar, and the guitar shape is a hydrogen nebula. The nebula was formed when particles being ejected by the pulsar produced a cloud of bubbles. The bubbles were then blown into a curvy guitar shape by a steady wind. The guitar shape is undeniable, and is traced by a thin white line in the labeled composite image.
The pulsar, known as PSR B2224+65, has also released a long filament of energetic matter and antimatter particles approximately 12 trillion miles long. In both the composite image and the six second video, this energetic, X-ray blast shoots from the bright white dot at the tip of the guitar’s headstock, all the way out to our upper righthand corner. In the still image, the blast resembles a streak of red dots, most of which fall in a straight, densely packed line. The six second video features four separate images of the phenomenon, created with Chandra data gathered in 2000, 2006, 2012, and 2021. When shown in sequence, the density of the X-ray blast filament appears to fluctuate.
A 12 second video is also included in this release. It features four images that focus on the headstock of the guitar shape. These images were captured by the Hubble Space Telescope in 1994, 2001, 2006, and 2021. When played in sequence, the images show the headstock shape expanding. A study of this data has concluded that the variations that drive the formation of bubbles in the hydrogen nebula also control changes in the pulsar’s blast filament. Meaning the same phenomenon that created the cosmic guitar also created the cosmic blowtorch shooting from the headstock.
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By European Space Agency
A new European Space Agency-backed study shows that the extreme heatwaves of 2023, which fuelled huge wildfires and severe droughts, also undermined the land’s capacity to soak up atmospheric carbon. This diminished carbon uptake drove atmospheric carbon dioxide levels to new highs, intensifying concerns about accelerating climate change.
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