Astronomers using NASA’s Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars. A gas giant planet circling the twin stars in the system OGLE-2007-BLG-349, located 8,000 light-years away.
The planet – with a mass similar to Saturn – orbits the two stars at a distance of roughly 480 million kilometers, about the distance from the asteroid belt to our Sun.
It completes an orbit around the stars roughly every 7 years. The twin stars are a mere 11 million kilometers apart, or 14 times the diameter of the moon’s orbit around Earth.
The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique. Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it.
The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets. The team’s results have been accepted for publication in The Astronomical Journal.