March 20, 2003
(PLANETQUEST) -- Observations with the European Southern Observatory's Very Large Telescope Interferometer (VLTI) have provided the first-ever direct determination of the angular sizes of the disks of the solar-type stars Alpha Centauri A and Alpha Centauri B.
Although the Centauri system is not known to harbor extrasolar planets, the finding demonstrates the capability of interferometers to resolve stellar objects with unprecedented accuracy. Interferometery has been identified by NASA as a key technology needed to study Earth-like planets around other stars. NASA's Space Interferometry Mission, the first space-based interferometer, is scheduled to launch in 2009 and will search for terrestrial planets.
The Alpha Centauri triple stellar system is our closest neighbor in space, located 4.36 light-years away in the direction of the southern constellation Centaurus (the Centaur). The two main stars in the system, Alpha Centauri A and Alpha Centauri B, are similar to the Sun, while the third star is a
"red dwarf" known as Proxima.
These new measurements of the Alpha Centauri A and Alpha Centauri B, combined with other observations, make them now the "best known" stars in our galaxy, apart from the Sun. This data has helped astronomers verify current theories about the structure and evolution of Sun-like stars, according to the European Southern Observatory.
The VLTI, a project of the European Southern Observatory, it to consists of four 8.2-meter telescopes and several moveable auxiliary telescopes at the ESO's Paranal Observatory in Atacama, Chile.
