Free Astronomy Magazine September-October 2014

EXOPLANETS 18 SEPTEMBER-OCTOBER 2014 The planetary system of a red dwarf rather close to the Sun has been literally halved by the re-examination of the material that enabled its discovery. Two of the three planets that vanished into thin air were considered very interesting from the habitability point of view. The phantom of Gliese 581 O ne of the most promising planetary systems among those with an envi- ronment potentially suitable for the existence of liquid water and perhaps life itself is Gliese 581 (GJ 581), a red dwarf star approximately 400000 kilometres in diame- ter (mass approximately 1/3 that of the Sun), easily visible in the constellation Libra. Now that system, consisting of 6 planets discovered between 2005 and 2010, has been significantly downsized by four re-