12 years ago, we didn't even know planets could exist around distant stars. Today, we know of almost 300 of them!
The exosolar planet session here at this year's NAM began with the announcement by Rachael Smith (Institute of Astronomy, University of Cambridge) of the astonishing discovery of two asteroid belts orbiting the star eta Tel.
Such a system may sound familiar to you... that is because we have two asteroid belts in our own solar system! In our solar system, one is between the orbits of Mars and Jupiter (the asteroid belt) and one is at the very edge of our solar system (the Kuiper-Edgeworth belt, of which Pluto appears to be the closest and largest member).
However, eta Tel is a very young system, only 12 million years old (our solar sytem is 4,500 million years old), and so eta Tel reminds us of how our solar system must have looked long ago, before Jupiter and Saturn formed. In fact, the asteroid belts in eta Tel may began to stick together to form two large planets in the future.
|Artist's impression of newly discovered planets around the star Ogle-2006-BLG-109 (Credit: KASI/CBNU/ARCSEC)|
Following on with the same theme, Martin Dominik (University of St Andrews) described a system called Ogle-2006-BLG-109, which contained two Jupiter-sized planets at 2.3 & 4.6 times the Sun-Earth separation - again, very similar to the planets Jupiter & Saturn in our solar system. In total, astronomers now know of 26 multiple planet systems, and 4 of these planets are in habitable zones - the location around a star that is neither too hot or too cold for life.
Astronomer Elain Simpson of the Queen's University Belfast announced the discovery of 5 more planets using SuperWASP, with 2 more suspect planets. Elain initially discovered 44 possible planets, and by observing each and every one in more detail using the Nordic Optical Telescope, she discovered the 5 planets. All these planets are hot Jupiters - large planets, very close to their parent star.
It makes us all wonder when the first Earth-like planet will be found - This year? There is a European Space Agency mission being planned called Darwin which has the aim of finding traces of water, ozone & carbon dioxide around some of these distant planets, helping us to identify Earth-like planets in the very near future.