15 September 2008

First image of another planet around a sun-like star!

Posted by briony

Check it out – this is probably the first image of an extra solar planet around a Sun-like star!

More specifically, the image above shows both the primary and companion of the star 1RXSJ160929.1-210524 (romantic, eh?), imaged at the Gemini North Telescope on Mauna Kea in Hawaii. The companion is about 8 times the mass of Jupiter, and has a radius about 17% of the Sun’s. One of the reasons that the team was able to image the planet so clearly is that it’s orbiting really far away from it’s star – 330 AU! (In our solar system, that would put it almost 7 times farther out than Pluto!) Planets that are close to their star are very difficult to find with imaging like this, since the light of the star washes out the light from the planet. For more info on how a planet could have ended up so far away from it’s star, look here.

The planet was found as part of a survey of 85 young (~5 million year old) stars in the same stellar group, about 150 Mpc away. The other very cool part of this discovery is that this is a fairly random star in a fairly random group of young stars, and it has a planet. This (along with all the planets found with other methods) is a fantastic piece of evidence that planets are common,

For those that want to get into the technical details, here’s the pre-print of the paper on the arXiv.  Just a note, this discovery has not been peer reviewed yet (to my knowledge), but since Gemini chose to release the press release, we can assume that they, at least, are pretty confident with the results.