Members Can Post Anonymously On This Site
One ESA: an interactive journey around ESA sites!
-
Similar Topics
-
By European Space Agency
Today, the European Space Agency signed six contracts that will help position Greece as a key player in the field of Earth observation.
View the full article
-
-
By NASA
NASA SkillBridge Veterans touring Johnson Space Center’s Neutral Buoyancy Laboratory.Credit: NASA NASA is one of America’s Best Employers for Veterans, according to Forbes and Statista. Statista surveyed more than 24,000 military veterans – having served in the United States Armed Forces – working for companies with a minimum of 1,000 employees. Veterans were asked to share opinions about their employer on factors such as working conditions, salary and pay, and topics of interest to the veteran community.
This is the fourth consecutive year NASA has earned this recognition.
“NASA has a long history of collaboration and commitment to the military community,” said Deborah Sweet, NASA Veterans Employment Program Manager. “In addition to the many military members who have been part of our Astronaut program, many of our civil servants are Veterans who chose to continue serving by supporting NASA’s mission after they hung up the uniform.”
Across the agency, veterans deliver subject matter expertise, years of on-the-job training, and advanced skills in everything from information technology to transportation logistics and from supply-chain management to public relations.
NASA continues to increase efforts to bring veterans into its ranks. The agency recently expanded its SkillBridge Fellowship Program which provides transitioning members a chance to gain valuable work experience while learning about NASA.
Veterans who served on active duty and separated under honorable conditions may also be eligible for special hiring authorities such as veterans’ preference, as well as other veteran specific hiring options when applying for full time roles at NASA.
For more information about the NASA SkillBridge Program, visit : https://www.nasa.gov/careers/skillbridge/
For more information about NASA hiring paths for Veterans and Military Spouses, visit: https://www.nasa.gov/careers/veterans-and-military-spouses/
View the full article
-
By European Space Agency
Space startups and SMEs can meet ESA’s SME Office at Space Tech Expo, a space technology trade fair and conference in Bremen, Germany from 19–21 November.
View the full article
-
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)
Download this image
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)
Download this image
“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)
Download this image
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
Share
Details
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
Hubble Space Telescope
Since its 1990 launch, the Hubble Space Telescope has changed our fundamental understanding of the universe.
James Webb Space Telescope
Space Telescope
Hubble vs. Webb
Hubble Focus: Strange New Worlds
NASA’s Hubble Space Telescope team has released a new edition in the Hubble Focus e-book series, called “Hubble Focus: Strange…
View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.