Artist's conception shows a Jupiter-sized planet forming from a disk of dust and gas
surrounding a young, massive star. The planet's gravity has cleared a gap in the disk.
Credit: David A. Aguilar, CfA
Most searches for planets around other stars, also known as exoplanets, focus on Sun-like stars. Those searches have proven successful, turning up more than 400 alien worlds.
The prospects for hypothetical alien life are, by opposite, disappointing. The habitable zone, or region where liquid water could exist on a rocky surface, is at a greater distance from the star for A and B stars than for sun-like stars due to their greater luminosity. However, that luminosity comes at the price of a short lifetime. A and B stars live for only about 10 - 500 million years before running out of fuel. (read more)