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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 European Space Agency
Video: 00:04:30 Explore the immense power of water as ESA’s Mars Express takes us on a flight over curving channels, streamlined islands and muddled ‘chaotic terrain’ on Mars, soaking up rover landing sites along the way.
This beautiful flight around the Oxia Palus region of Mars covers a total area of approximately 890 000 km2, more than twice the size of Germany. Central to the tour is one of Mars’s largest outflow channels, Ares Vallis. It stretches for more than 1700 km2 and cascades down from the planet’s southern highlands to enter the lower-lying plains of Chryse Planitia.
Billions of years ago, water surged through Ares Vallis, neighbouring Tiu Vallis, and numerous other smaller channels, creating many of the features observed in this region today.
Enjoy the flight!
After enjoying a spectacular global view of Mars we focus in on the area marked by the white rectangle. Our flight starts over the landing site of NASA’s Pathfinder mission, whose Sojourner rover explored the floodplains of Ares Vallis for 12 weeks in 1997.
Continuing to the south, we pass over two large craters named Masursky and Sagan. The partially eroded crater rim of Masursky in particular suggests that water once flowed through it, from nearby Tiu Vallis.
The Masurky Crater is filled with jumbled blocks, and you can see many more as we turn north to Hydaspis Chaos. This ‘chaotic terrain’ is typical of regions influenced by massive outflow channels. Its distinctive muddled appearance is thought to arise when subsurface water is suddenly released from underground to the surface. The resulting loss of support from below causes the surface to slump and break into blocks of various sizes and shapes.
Just beyond this chaotic array of blocks is Galilaei crater, which has a highly eroded rim and a gorge carved between the crater and neighbouring channel. It is likely that the crater once contained a lake, which flooded out into the surroundings. Continuing on, we see streamlined islands and terraced river banks, the teardrop-shaped island ‘tails’ pointing in the downstream direction of the water flow at the time.
Crossing over Ares Vallis again, the flight brings us to the smoother terrain of Oxia Planum and the planned landing site for ESA’s ExoMars Rosalind Franklin rover. The primary goal of the mission is to search for signs of past or present life on Mars, and as such, this once water-flooded region is an ideal location.
Zooming out, the flight ends with a stunning bird’s-eye view of Ares Vallis and its fascinating water-enriched neighbourhood.
Disclaimer: This video is not representative of how Mars Express flies over the surface of Mars. See processing notes below.
How the movie was made
This film was created using the Mars Express High Resolution Stereo Camera Mars Chart (HMC30) data, an image mosaic made from single orbit observations of the High Resolution Stereo Camera (HRSC). The mosaic, centred at 12°N/330°E, is combined with topography information from the digital terrain model to generate a three-dimensional landscape.
For every second of the movie, 50 separate frames are rendered following a predefined camera path in the scene. A three-fold vertical exaggeration has been applied. Atmospheric effects such as clouds and haze have been added to conceal the limits of the terrain model. The haze starts building up at a distance of 300 km.
The HRSC camera on Mars Express is operated by the German Aerospace Center (DLR). The systematic processing of the camera data took place at the DLR Institute for Planetary Research in Berlin-Adlershof. The working group of Planetary Science and Remote Sensing at Freie Universität Berlin used the data to create the film.
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By NASA
Hubble Space Telescope Home NASA’s Hubble, Webb… 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 6 Min Read NASA’s Hubble, Webb Probe Surprisingly Smooth Disk Around Vega
Teams of astronomers used the combined power of NASA’s Hubble and James Webb space telescopes to revisit the legendary Vega disk. Credits:
NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona) In the 1997 movie “Contact,” adapted from Carl Sagan’s 1985 novel, the lead character scientist Ellie Arroway (played by actor Jodi Foster) takes a space-alien-built wormhole ride to the star Vega. She emerges inside a snowstorm of debris encircling the star — but no obvious planets are visible.
It looks like the filmmakers got it right.
A team of astronomers at the University of Arizona, Tucson used NASA’s Hubble and James Webb space telescopes for an unprecedented in-depth look at the nearly 100-billion-mile-diameter debris disk encircling Vega. “Between the Hubble and Webb telescopes, you get this very clear view of Vega. It’s a mysterious system because it’s unlike other circumstellar disks we’ve looked at,” said Andras Gáspár of the University of Arizona, a member of the research team. “The Vega disk is smooth, ridiculously smooth.”
The big surprise to the research team is that there is no obvious evidence for one or more large planets plowing through the face-on disk like snow tractors. “It’s making us rethink the range and variety among exoplanet systems,” said Kate Su of the University of Arizona, lead author of the paper presenting the Webb findings.
[left] A Hubble Space Telescope false-color view of a 100-billion-mile-wide disk of dust around the summer star Vega. Hubble detects reflected light from dust that is the size of smoke particles largely in a halo on the periphery of the disk. The disk is very smooth, with no evidence of embedded large planets. The black spot at the center blocks out the bright glow of the hot young star.
[right] The James Webb Space Telescope resolves the glow of warm dust in a disk halo, at 23 billion miles out. The outer disk (analogous to the solar system’s Kuiper Belt) extends from 7 billion miles to 15 billion miles. The inner disk extends from the inner edge of the outer disk down to close proximity to the star. There is a notable dip in surface brightness of the inner disk from approximately 3.7 to 7.2 billion miles. The black spot at the center is due to lack of data from saturation. NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona)
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Webb sees the infrared glow from a disk of particles the size of sand swirling around the sizzling blue-white star that is 40 times brighter than our Sun. Hubble captures an outer halo of this disk, with particles no bigger than the consistency of smoke that are reflecting starlight.
The distribution of dust in the Vega debris disk is layered because the pressure of starlight pushes out the smaller grains faster than larger grains. “Different types of physics will locate different-sized particles at different locations,” said Schuyler Wolff of the University of Arizona team, lead author of the paper presenting the Hubble findings. “The fact that we’re seeing dust particle sizes sorted out can help us understand the underlying dynamics in circumstellar disks.”
The Vega disk does have a subtle gap, around 60 AU (astronomical units) from the star (twice the distance of Neptune from the Sun), but otherwise is very smooth all the way in until it is lost in the glare of the star. This shows that there are no planets down at least to Neptune-mass circulating in large orbits, as in our solar system, say the researchers.
Hubble acquired this image of the circumstellar disk around the star Vega using the Space Telescope Imaging Spectrograph (STIS). NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona)
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“We’re seeing in detail how much variety there is among circumstellar disks, and how that variety is tied into the underlying planetary systems. We’re finding a lot out about the planetary systems — even when we can’t see what might be hidden planets,” added Su. “There’s still a lot of unknowns in the planet-formation process, and I think these new observations of Vega are going to help constrain models of planet formation.”
Disk Diversity
Newly forming stars accrete material from a disk of dust and gas that is the flattened remnant of the cloud from which they are forming. In the mid-1990s Hubble found disks around many newly forming stars. The disks are likely sites of planet formation, migration, and sometimes destruction. Fully matured stars like Vega have dusty disks enriched by ongoing “bumper car” collisions among orbiting asteroids and debris from evaporating comets. These are primordial bodies that can survive up to the present 450-million-year age of Vega (our Sun is approximately ten times older than Vega). Dust within our solar system (seen as the Zodiacal light) is also replenished by minor bodies ejecting dust at a rate of about 10 tons per second. This dust is shoved around by planets. This provides a strategy for detecting planets around other stars without seeing them directly – just by witnessing the effects they have on the dust.
“Vega continues to be unusual,” said Wolff. “The architecture of the Vega system is markedly different from our own solar system where giant planets like Jupiter and Saturn are keeping the dust from spreading the way it does with Vega.”
Webb acquired this image of the circumstellar disk around the star Vega using the Mid-Infrared Instrument (MIRI). NASA, ESA, CSA, STScI, S. Wolff (University of Arizona), K. Su (University of Arizona), A. Gáspár (University of Arizona)
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For comparison, there is a nearby star, Fomalhaut, which is about the same distance, age and temperature as Vega. But Fomalhaut’s circumstellar architecture is greatly different from Vega’s. Fomalhaut has three nested debris belts.
Planets are suggested as shepherding bodies around Fomalhaut that gravitationally constrict the dust into rings, though no planets have been positively identified yet. “Given the physical similarity between the stars of Vega and Fomalhaut, why does Fomalhaut seem to have been able to form planets and Vega didn’t?” said team member George Rieke of the University of Arizona, a member of the research team. “What’s the difference? Did the circumstellar environment, or the star itself, create that difference? What’s puzzling is that the same physics is at work in both,” added Wolff.
First Clue to Possible Planetary Construction Yards
Located in the summer constellation Lyra, Vega is one of the brightest stars in the northern sky. Vega is legendary because it offered the first evidence for material orbiting a star — presumably the stuff for making planets — as potential abodes of life. This was first hypothesized by Immanuel Kant in 1775. But it took over 200 years before the first observational evidence was collected in 1984. A puzzling excess of infrared light from warm dust was detected by NASA’s IRAS (Infrared Astronomy Satellite). It was interpreted as a shell or disk of dust extending twice the orbital radius of Pluto from the star.
In 2005, NASA’s infrared Spitzer Space Telescope mapped out a ring of dust around Vega. This was further confirmed by observations using submillimeter telescopes including Caltech’s Submillimeter Observatory on Mauna Kea, Hawaii, and also the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and ESA’s (European Space Agency’s) Herschel Space Telescope, but none of these telescopes could see much detail. “The Hubble and Webb observations together provide so much more detail that they are telling us something completely new about the Vega system that nobody knew before,” said Rieke.
Two papers (Wolff et al. and Su et. al.) from the Arizona team will be published in The Astrophysical Journal.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
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, Colorado, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, Maryland, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
Explore More:
Finding Planetary Construction Zones
The science paper by Schuyler Wolff et al., PDF (3.24 MB)
The science paper by Kate Su et al., PDF (2.10 MB)
Facebook logo @NASAHubble @NASAHubble Instagram logo @NASAHubble Facebook logo @NASAWebb @NASAWebb Instagram logo @NASAWebb Media Contacts:
Claire Andreoli (claire.andreoli@nasa.gov), Laura Betz (laura.e.betz@nasa.gov)
NASA’s Goddard Space Flight Center, Greenbelt, MD
Ray Villard, Christine Pulliam
Space Telescope Science Institute, Baltimore, MD
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Last Updated Nov 01, 2024 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Related Terms
Astrophysics Goddard Space Flight Center Hubble Space Telescope James Webb Space Telescope (JWST) Stars Keep Exploring Discover More Topics From Hubble and Webb
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NASA’s Hubble Space Telescope team has released a new edition in the Hubble Focus e-book series, called “Hubble Focus: Strange…
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By USH
The world is full of mysterious places, and Vottovaara Mountain in Russia's Republic of Karelia is one of them. This site has been revered for thousands of years by ancient Saami tribes and shamans, who considered it a sacred place surrounded with powerful energy.
Image credit: Universe Inside You
Vottovaara is home to numerous strange megalithic structures and ruins that many believe couldn't have formed naturally. Among these are around 1,600 sacred stones, known as "seids," arranged in a puzzling pattern. These stones, often unusually shaped, are precariously balanced on small rocks in ways that defy simple explanations. While scientists suggest that this was the result of natural processes during the Ice Age, the sheer number and precision of these balanced stones challenge the idea that they occurred by chance.
Another intriguing feature of Vottovaara is a structure referred to as "the well," which locals believe to be an ancient, man-made water reservoir.
As you climb Vottovaara, you'll notice an eerie transformation in the trees. None of the trees on the summit are older than a few decades, and while young pines and firs start growing normally, they soon begin to twist and deform in bizarre ways. This phenomenon is thought to be caused by some unknown energy affecting the trees.
Known as Death Mountain, Vottovaara also is believed to be connected to ancient spirits that are said to inhabit the area, adding to its aura of mystery.
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By European Space Agency
ESA’s star-surveying Gaia mission has again proven to be a formidable asteroid explorer, spotting potential moons around more than 350 asteroids not known to have a companion.
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