Thursday, January 31, 2008
New planet outside solar system discovered
A group of astronomers at the Universidad de Santiago de Compostela (USC) has discovered a huge planet in the star system Gliese 22, Spain's EFE news agency reported Wednesday. The finding has been reported in the Astronomy and Astrophysics magazine. According to Jose A. Docobo, director of the Ramon Maria Aller Astronomical Observatory at the university - the discovery of the extra-solar planet was made using for the first time a discipline called astrometry that studies the position and movement of stars and other bodies in the universe. Till the discovery in the Gliese 22 system, planets outside our own solar system have been discovered by measuring their stars' radial velocities or by observing the slight reduction in the stars' light that occurs when an orbiting star passes directly between it and us. The Gliese 22 star system is made up of three low-mass stars. Two of them form a binary system, in which both circle around a common centre of mass, while the third star - the most distant of the trio - circles around the other two. The existence of the enormous planet, which is calculated to have 16 times the mass of Jupiter - our solar system's largest planet, was detected around the third lone star. The astronomer team noticed that the third star moves from side to side a little as it orbits the binary system. Investigators said the oscillating motion could only be explained by the presence of another body - the large planet - circling it and pulling it slightly back and forth.