Wednesday, June 10, 2009
That's right, in a whole other galaxy. Now we're talking about a distance of 2.5 million light years instead of what we are more used to with extrasolar planets - 20 LY, 200 LY, etc. An article on a paper detailing the method used can be seen here. The reason this is possible is due to a feature of gravitational microlensing that actually makes it easier to use from a greater distance, as the optical depth increases with the distance from the star. Other techniques become less precise as the distance increases and thus can't be used (yet!) to determine whether stars in other galaxies have extrasolar planets, according to the authors of the paper.
Here's the part of the paper that details this possible discovery:
What is interesting about this is that it gives the first opportunity to compare planetary systems in this galaxy with those in other galaxies...and the fact that we can detect planets 2.5 million light years away. Damn.
You can find the pdf here.
As for the planet, it has a mass six times that of Jupiter, which is about half the mass an object needs to first be considered a brown dwarf.