Using data from NASA’s Kepler mission, two teams of astronomers, led by Mauricio Ortiz from the University of Heidelberg and Simona Ciceri of the Max Planck Institute for Astronomy, have independently discovered a new extrasolar gas giant that is almost six times more massive than Jupiter, but about the same size.
The shape and the size of its orbit are also unusual for a planet like Kepler-432b that is revolving around a giant star. In less than 200 million years, this “red giant” will most likely swallow up the planet.
“The majority of known planets moving around giant stars have large and circular orbits. With its small and highly elongated orbit, Kepler-432b is a real ‘maverick’ among planets of this type,” says Dr. Davide Gandolfi from the state observatory Königstuhl, which is part of the Centre for Astronomy.
He explains that the star around which Kepler-432b is orbiting has already exhausted the nuclear fuel in its core and is gradually expanding. Its radius is already four times that of our Sun and it will get even larger in the future. As the star is reddish in colour, astronomers call it a “red giant”.
“During the winter season, the temperature on Kepler-432b is roughly 500 degrees Celsius,” said Dr Sabine Reffert, also from the University of Heidelberg.
“In the short summer season, it can increase to nearly 1,000 degrees Celsius.”
Mauricio Ortiz added: “the days of Kepler-432b are numbered, though. In less than 200 million years, the planet will be swallowed by its continually expanding host star.”
“This might be the reason why we do not find other planets like Kepler-432b – astronomically speaking, their lives are extremely short.”
Kepler-432b was previously identified as a transiting planet candidate by the Nasa Kepler satellite mission.
Both groups of researchers used the 2.2-metre telescope at Calar Alto Observatory in Andalucía, Spain to collect data. The group from the state observatory also observed Kepler-432b with the Nordic Optical Telescope on La Palma (Canary Islands).