Vega Asteroid Belt Suggests Multiple Planets


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Astronomers this week announced that they have discovered what could be an asteroid belt around the star Vega. NASA's Spitzer space telescope and the European Space Agency's (ESA) Herschel Space Observatory were used to observe the star, which is the second brightest in the northern sky.

Vega was found to have an astroid belt-like band of debris in both a warm inner band and cool outer band. This is similar to our own solar system, which features an asteroid belt and an outer kuiper belt where dwarf planets such as Pluto and Makemake are located. This could suggest that the gap between Vega's belts is inhabited by multiple planets.

"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 Kate Su, an astronomer at the Steward Observatory at the University of Arizona and the lead author of a paper describing the new findings, published recently in The Astrophysical Journal.

Vega is similar to another star with an asteroid belt, named Fomalhaut. Both are only 25 light-years away from Earth, but burn brighter and hotter than our sun, with around double its mass and a bluer tinge. The space telescopes were able to detect the infrared light emitted by the warm and cold dust in Vega's bands, where comets and collisions replenish the dust.

"Our findings echo recent results showing multiple-planet systems are common beyond our sun," said Su.

Su and her colleagues predict that the planets orbiting Veta and Fomalhaut, if they exist, will be spotted by future telescopes such as the James Webb Space Telescope, scheduled to be launched in 2018.