Rare planet with extreme seasons discovered

The teams, one led by Mauricio Ortiz of the Centre for Astronomy of Heidelberg University (ZAH) and the other by Simona Ciceri of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, report that the planet has six times the mass of Jupiter, but about the same size.

Researchers have discovered one of the most dense and massive planets known so far with extreme seasons.

The teams, one led by Mauricio Ortiz of the Centre for Astronomy of Heidelberg University (ZAH) and the other by Simona Ciceri of the Max Planck Institute for Astronomy (MPIA) in Heidelberg, report that the planet has six times the mass of Jupiter, but about the same size.

The shape and the size of its orbit are also unusual for the planet named 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, researchers said.

'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,' said Dr Davide Gandolfi from the state observatory Konigstuhl, which is part of the Centre for Astronomy.

Gandolfi explained 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.'

The orbit brings Kepler-432b incredibly close to its host star at some times and much farther away at others, thus creating enormous temperature differences over the course of the planet's year, which corresponds to 52 Earth days.

'During the winter season, the temperature on Kepler-432b is roughly 500 degrees Celsius. In the short summer season, it can increase to nearly 1,000 degrees Celsius,' said astronomer Dr Sabine Reffert from the state observatory Konigstuhl.

Kepler-432b was previously identified as a transiting planet candidate by the NASA Kepler satellite mission. From the vantage point of Earth, a transiting planet passes in front of its host star, periodically dimming the received stellar light.

Both groups of researchers used the 2.2-metre telescope at Calar Alto Observatory in Andalucia, Spain to collect data. The group from the state observatory also observed Kepler-432b with the Nordic Optical Telescope on La Palma.

The research was published in the journal Astronomy and Astrophysics.