Uranus-Sized Planet Discovered with Gravitational Microlensing

First Posted: Jul 31, 2015 04:26 PM EDT

Scientists have discovered a new, Uranus-sized planet with the help of gravitational microlensing. The new findings reveal that it's possible to uncover planets as far from their central stars as Jupiter and Saturn are from our sun.

A large majority of the exoplanets catalogued so far are very close to their host stars. This is largely because current planet-hunting techniques favor finding planets in short-period orbits. However, this isn't the case with the microlensing technique, which can find more distant and colder planets in a long-period orbits that others methods can't detect.

In this latest study, the researchers looked at the system OGLE-2005-BLG-169. This system was discovered in 2005, but it only wasn't until now that researchers have now found that the system consists of a Uranus-sized planet orbiting about 370 million miles from its parent star, which is about 70 percent as massive as our sun.

In order to study this system, the researchers used microlensing. Microlensing occurs when a foreground star amplifies the light of a background star that momentarily aligns with it. If the foreground star has planets, then the planets may also amplify the light of the background star.

"These chance alignments are rare, occurring only once every 1 million years for a given planet, so it was thought that a very long wait would be required before the planetary microlensing signal could be confirmed," said David Bennett, one of the researchers, in a news release. "Fortunately, the planetary signal predicts how fast the apparent positions of the background star and planetary host star will separate, and our observations have confirmed this prediction. The Hubble and Keck Observatory data, therefore, provide the first confirmation of a planetary microlensing signal."

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TagsPlanet, Exoplanets, Microlensing