Astronomers find planets 'being formed'

Radio image of dust disc showing gap at centre

Astronomers have obtained the first pictures of huge dust discs circling two of the brightest stars in the sky. The images may reveal that the formation of planetary systems around stars may be more common than previously believed. Our science correspondent David Whitehouse reports.

Astronomers have made two discoveries that may shed light on the number of planetary systems orbiting other stars.

It is believed the planets circling our Sun were formed out of a disc of dust. Clumps formed in the ring of debris and grew to become planets.

Astronomers may now be seeing this process in action around other stars.

A very young star called HR 4796A

A British and American team has used the James Clerk Maxwell radio telescope at the Mauna Kea Observatory in Hawaii to look at some bright stars. Mounted high on an extinct volcano, the scientists have a clear view of the stars.

When it was turned towards Fomalhaut, a 200 million-year-old star, it detected radiation from an orbiting dust ring. But the astronomers were excited most by what appears to be a gap in the disc near the star.

Discoveries were made using James Clerk Maxwell telescope in Hawaii

One explanation is that the dust in the disc's central region has formed planets. And, according to Wayne Holland and Jane Greaves, the dust disk around Fomalhaut is similar to one that circled the Sun before its planets were born.

Meanwhile, a team of astronomers working at observatories in Chile and Hawaii believe they have detected a planetary system in the act of being born around a very young star called HR 4796A.

The last few years have seen a revolution in the understanding about the number of planets that may circle other stars. As well as the observations reported here, astronomers have detected evidence for large planets circling many of the closest stars to the Sun.

The universe seems to be teeming with planets, giving scientists hope that some form of life may have developed elsewhere in space.