NASA`s Kepler identifies new `circumbinary` planet orbiting two stars

Washington DC: NASA's Kepler has detected a new "circumbinary" planet orbiting a pair of stars.

A team of astronomers including a San Francisco State University researcher found the new planet known as Kepler-453b, which is the 10th one discovered by NASA's Kepler Mission and a milestone for the 6-year-old spacecraft.

The planet is located within its host stars' "habitable zone," the area around the stars in which life could potentially exist. And the somewhat fortuitous nature of its discovery indicate there could be more like it than previously believed, according to Stephen Kane, an assistant professor of physics and astronomy at San Francisco State University and member of the team that made the discovery.

Had researches not detected the planet now, their next chance to do so would not have come until 2066.

Kepler-453b blocked 0.5 percent of its host stars' light during the transit, which enabled researchers to calculate that the planet's radius is 6.2 times that of Earth, or about 60 percent larger than Neptune. Its size indicates it is a gas giant, rather than a rocky planet, and thus unable to have life despite being in the habitable zone.

However, it could have moons that are rocky, which means it was possible to have life on the moons in this system, Kane said.

Any inhabitants of the system would see two suns in their sky orbiting each other every 27 days. The larger star is about 94 percent the size of our sun, the smaller star only 20 percent the size of our sun and much cooler, emitting less than 1 percent of the larger star's energy. Kepler-453b takes 240 days to orbit its host stars.

Kane said that they didn't know circumbinary systems could exist until Kepler came along, and since then they'd been finding them in larger numbers. The first two-star system was discovered by the Kepler Mission in 2011.

The finding is due to be published in the Astrophysical Journal.