NEW PLANETS NEAR VEGA
Date: Tue, 29 Jan 2002
Scientists announced that the two giant clumps of dust in the ring surrounding the star Vega may be planets. Vega is located 25 light years away in the constellation Lyra and is the brightest star in the summer sky. The planets are apparently trapped in this dust ring.
Observations of Vega in 1983 with the Infrared Astronomy Satellite provided the first evidence for large dust particles around another star, probably debris related to the formation of planets. This discovery likely inspired Carl Sagan to place the alien listening post at Vega in his novel "Contact." In our Solar System, dust particles created by asteroid collisions spiral in toward the Sun. The gravity of the planets affect the distribution of these dust particles.
The Earth, for example, traps dust in a series of dynamical resonance's that produce a ring of enhanced density along the Earth's orbit. When viewed from Earth, the signatures of extrasolar planets imprinted on circumstellar dust may be the most conspicuous evidence of their existence. Up to now more than fifty planets have been detected by their gravitational influence on their own stars.
The dust clouds are much easier to detect than the planets because of their much larger surface area. It's akin to seeing the wake of a boat from a plane when the boat itself is too small to be visible. Because Vega is viewed nearly pole-on, it presents a perfect target for more detailed study of planets in its dust cloud.