Planet: The most distant known planet has been detected orbiting a star 17,000 light-years away, say astronomers.

The find was made through measurements of the effect the combined mass of the planet and its parent star had on the light of another, more distant star.

Comet: The star has a mass of about six times the mass of our Sun and an estimated very young age of about 100,000 years.

"This detection indicates that solid bodies of 100km in size can form this early around a star," Ge says.

Five sets of observations taken during October and November 2003 indicated that the star's light was absorbed by clouds of hydrogen and helium surrounding it.

Scientists believe that the gas clouds were the wreckage of a comet that got too close.