Monday, June 15, 2009

First planet spotted outside the Milky Way may lie in Andromeda galaxy

A team of astronomers has claimed to have seen hints of the first planet to be spotted outside the Milky Way galaxy, in the Andromeda galaxy.
According to a report by BBC News, the team, which has made the finding, is made up of researchers from the National Institute of Nuclear Physics (INFN) in Italy and collaborators in Switzerland, Spain, and Russia.
They exploited a type of gravitational lensing called microlensing to make the discovery.
The effect of large, massive objects between an observer and a distant planet or star can cause distortion or multiple images as the intermediary object's gravity bends the passing light.
Microlensing, by contrast, occurs when a less massive object lies in the middle. The technology is in place to truly see planets of Jupiter's mass and even less in other galaxies
Francesco De Paolis of the INFN and his colleagues developed a computer model to determine the likelihood of detecting an exoplanet via a microlensing event in the Andromeda galaxy.
They modelled the "light curve", the variation in light that a microlensed star would exhibit if it were being orbited by a companion - another star or a planet.
Having determined the clues that a planet in Andromeda would show, they returned to a survey completed in 2004 by the Point-Agape collaboration of astronomers that showed an unusual light curve.
That event, the group says, matches up to its theory and can be attributed to a companion of a mass about six times that of Jupiter.
That suggests either a planet, or a small companion star such as a brown dwarf.
Unfortunately, given that microlensing events from a given pair of objects happens just once, astronomers cannot return to the planet candidate to confirm the idea.
But, Dr De Paolis is encouraged by the possibility of detecting planets at such phenomenal distances.
"The interesting thing is that the technology is in place to truly see planets of Jupiter's mass and even less in other galaxies. It's an exceptional thing," he told BBC News.
Armed with the new theory, the authors of the work are looking to secure time on a larger telescope to continue with their observations in the hope of finding more candidates.
With about 350 extra-solar planets already found in our galactic neighbourhood, Dr De Paolis said, it was likely that such candidates were abundant. (ANI)
ANI

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