Hubble Space Telescope Spots Exoplanet Orbiting 2 Stars
Using NASA's Hubble Space Telescope, astronomers have confirmed the presence of a new alien planet that orbits around a pair of stars.
In a new study to be published in The Astronomical Journal, scientists reported about the exoplanet located 8,000 light-years away from Earth that orbits a pair of red dwarf stars about every seven years.
The twin stars in the binary system OGLE-2007-BLG-349 are separated by a distance of only about 7 million miles, or about 14 times the diameter of the orbit of the moon around planet Earth. The planet, on the other hand, orbits the stellar bodies from a proximity of 300 million miles, which is about the same distance from the asteroid belt to the sun.
The planet was first observed in 2007 through gravitational microlensing. The phenomenon, which was first predicted by physicist Albert Einstein, occurs when gravity from a foreground star bends the light of a background star that aligns with it. The effect is comparable to that of a glass lens and is capable of discovering planets that are too far from Earth.
The 2007 microlensing event observed a trio of distortions. The ground-based observations unveiled a planet and a star. Analysis also showed a third body albeit astronomers could not definitely identify it.
David Bennett, from NASA Goddard Space Flight Center in Greenbelt, Maryland, said the ground-based observations hint of either a Saturn-mass planet that orbits a close binary star system, or an Earth-mass or Saturn-mass exoplanet that orbits one star.
Newly collected data from the Hubble Space Telescope, however, allowed scientists to confirm the existence of two stellar sources and a sizable exoplanet. Using Hubble data, the researchers found that the light from the foreground lens system was very faint to be a lone star. The brightness likewise characterizes closely orbiting pair of red dwarf stars that are less massive and fainter than the sun.
The discovery is not the first time that astronomers found a planet that orbits two stars just like the fictional world of Tatooine in Star Wars. Earlier this year, astronomers reported that the Kepler space telescope discovered the largest known planet in a twin star system.
The newly found planet, however, is the first one to be discovered using the light bending technique gravitational microlensing.
""We present the first circumbinary planet found by microlensing, OGLE-2007-BLG-349L(AB)," the researchers wrote in their study [PDF]. "The system consists of two host stars, OGLE-2007-BLG-349LA and OGLE-2007-BLG-349LB, orbited by a planet somewhat less massive than Saturn."
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