Hubble Finds Planet Orbiting Pair Of Stars

Using NASA’s Hubble Space Telescope observations and a promising technique that spots gravitational microlensing, or bending of light that passes between celestial objects, astronomers finally were able to determine that the third object they had identified was indeed a star.

This isn’t the first time that scientists have discovered a planet orbiting twin stars- a configuration sometimes compared to the planet Tatooine from “Star Wars”.

The exoplanet was named OGL-2007-BLG-349 and is located 8,000 light years from Earth, near the center of the Milky Way. The exoplanet would therefore complete one orbit around the binary every seven years.

In this handout from the National Aeronautical Space Administration (NASA), the Hubble Space Telescope drifts through space in a picture taken from the Space Shuttle Discovery during Hubble?s second servicing mission in 1997.

According to the Seeker, the two red dwarfs are orbiting one another only 7 million miles apart.

The circumbinary planet is not a natural occurrence because most exoplanets in the universe usually orbit just one star. It’s about 300 million miles away from its suns, which is roughly the distance from the ribbon of asteroids located between Mars and Jupiter to our sun.

The Hubble Space Telescope. David Bennett of NASA’s Goddard Space Flight Center said that it could be a Saturn-mass planet orbiting a close binary star pair. The phenomenon occurs when light is bent by strong gravity around objects in space. Further analysis revealed that the single gas giant orbiting a pair of red dwarfs was the only theory consistent with the observed data.

While the system was first found in 2007, at that time experts were uncertain whether it contained one planet and two stars, or two planets and one star.

“OGLE has detected over 17,000 microlensing events, but this is the first time such an event has been caused by a circumbinary planetary system”, explains Andrzej Udalski from the University of Warsaw, Poland, co-author of the study. While Kepler is more likely to detect planets with small orbits – and indeed all the circumbinary planets it discovered are very close to the lower limit of a stable orbit – microlensing allows planets to be found at distances far from their host stars.

Their research has successfully demonstrated that microlensing can detect planets orbiting double-star systems, the authors noted, suggesting that Hubble and its successors may be a powerful tool in the ongoing hunt for new and potentially habitable exoplanets.

An artist’s illustration shows an exoplanet named OGLE-2007-BLG-349.

“This discovery, suggests we need to rethink our observing strategy when it comes to stellar binary lensing events”, said Yiannis Tsapras, another member of the team, from the Astronomisches Recheninstitut in Heidelberg, Germany. Hubble’s high-resolution images revealed that the system has the brightness expected of two closely orbiting red dwarf stars.