Space

January 10, 2013

NASA, ESA telescopes find evidence for asteroid belt around Vega

Astronomers have discovered what appears to be a large asteroid belt around the star Vega, the second brightest star in northern night skies. The scientists used data from NASA’s Spitzer Space Telescope and the European Space Agency’s Herschel Space Observatory, in which NASA plays an important role.

The discovery of an asteroid belt-like band of debris around Vega makes the star similar to another observed star called Fomalhaut. The data are consistent with both stars having inner, warm belts and outer, cool belts separated by a gap. This architecture is similar to the asteroid and Kuiper belts in our own solar system.

What is maintaining the gap between the warm and cool belts around Vega and Fomalhaut? The results strongly suggest the answer is multiple planets. Our solar system’s asteroid belt, which lies between Mars and Jupiter, is maintained by the gravity of the terrestrial planets and the giant planets, and the outer Kuiper belt is sculpted by the giant planets.

“Our findings echo recent results showing multiple-planet systems are common beyond our sun,” said Kate Su, an astronomer at the Steward Observatory at the University of Arizona. Su presented the results Tuesday at the American Astronomical Society meeting in Long Beach, Calif., and is lead author of a paper on the findings accepted for publication in the Astrophysical Journal.

Vega and Fomalhaut are similar in other ways. Both are about twice the mass of our sun and burn a hotter, bluer color in visible light. Both stars are relatively nearby at about 25 light-years away. The stars are thought to be around 400 million years old, but Vega could be closer to its 600 millionth birthday. Fomalhaut has a single candidate planet orbiting it, Fomalhaut b, which orbits at the inner edge of its cometary belt.

The Herschel and Spitzer telescopes detected infrared light emitted by warm and cold dust in discrete bands around Vega and Fomalhaut, discovering the new asteroid belt around Vega and confirming the existence of the other belts around both stars. Comets and the collisions of rocky chunks replenish the dust in these bands. The inner belts in these systems cannot be seen in visible light because the glare of their stars outshines them.

Both the inner and outer belts contain far more material than our own asteroid and Kuiper belts. The reason is twofold: the star systems are far younger than our own, which has had hundreds of millions more years to clean house, and the systems likely formed from an initially more massive cloud of gas and dust than our solar system.

The gap between the inner and outer debris belts for Vega and Fomalhaut also proportionally corresponds to the distance between our sun’s asteroid and Kuiper belts. This distance works out to a ratio of about 1:10, with the outer belt 10 times farther away from its host star than the inner belt. As for the large gap between the two belts, it is likely there are several undetected planets, Jupiter-sized or smaller, creating a dust-free zone between the two belts. A good comparison star system is HR 8799, which has four known planets that sweep up the space between two similar disks of debris.

“Overall, the large gap between the warm and the cold belts is a signpost that points to multiple planets likely orbiting around Vega and Fomalhaut,” said Su.

If unseen planets do in fact orbit Vega and Fomalhaut, these bodies will not likely stay hidden.

“Upcoming new facilities such as NASA’s James Webb Space Telescope should be able to find the planets,” said paper co-author Karl Stapelfeldt, chief of the Exoplanets and Stellar Astrophysics Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md.

 




All of this week's top headlines to your email every Friday.


 
 

 

NASA awards modification for geophysics, geodynamics, space geodesy support contract

NASA has awarded a modification to Stinger Ghaffarian Technologies Inc. of Greenbelt, Md. to continuing working the the Geophysics, Geodynamics and Space Geodesy Support Services contract. The maximum ordering value of the GGSG contract will increase to $76.8 million. The previous amount was $49.5 million. The increase in the maximum ordering value of the contract...
 
 
NASA/DOE/Fermi LAT Collaboration

NASA’s Fermi telescope reveals new source of gamma rays

NASA/DOE/Fermi LAT Collaboration These images show Fermi data centered on each of the four gamma-ray novae observed by the LAT. Colors indicate the number of detected gamma rays with energies greater than 100 million electron v...
 
 

NASA awards mission operations support contract extension

NASA has awarded a contract extension to Lockheed Martin of Gaithersburg, Md., for the Facilities Development and Operations Contract at the agency’s Johnson Space Center in Houston. This $340.6 million three-year extension includes a two-year base period and a one-year option. The extension base period runs from Oct. 1 through Sept. 30, 2016. If exercised,...
 

 
NASA and ESA

Hubble shows farthest lensing galaxy yields clues to early universe

NASA and ESA The farthest cosmic lens yet found, a massive elliptical galaxy, is shown in the inset image at left. The galaxy existed 9.6 billion years ago and belongs to the galaxy cluster, IRC 0218. Astronomers using NASAR...
 
 
NASA/JPL-Caltech

NASA announces Mars 2020 rover payload to explore Red Planet as never before

NASA/JPL-Caltech Planning for NASA’s 2020 Mars rover envisions a basic structure that capitalizes on the design and engineering work done for the NASA rover Curiosity, which landed on Mars in 2012, but with new science in...
 
 
NASA photograph by Carla Thomas

Katherine Lott awarded NASA Armstrong employee scholarship

NASA photograph by Carla Thomas Katherine Lott, the recipient of the 2014 NASA Armstrong Employee Exchange Council Joseph R. Vensel Memorial Scholarship, is congratulated by NASA Armstrong center director David McBride. Flankin...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>