Star set to swallow two exoplanets in 130 million and 155 million years

Astronomers have said that the planets Kepler-56b and Kepler-56c are going to be swallowed by their star in a short time by astronomical standards.

ANI| Last Updated: Jun 03, 2014, 10:40 AM IST

Washington: Astronomers have said that the planets Kepler-56b and Kepler-56c are going to be swallowed by their star in a short time by astronomical standards.

Their ends will come in 130 million and 155 million years, respectively.

Lead author Gongjie Li of the Harvard-Smithsonian Center for Astrophysics (CfA), said as far as they know, this is the first time two known exoplanets in a single system have a predicted "time of death."

The Kepler-56 system provides a glimpse into the future of our solar system. In about five billion years our Sun will become a red giant star, swelling to immense proportions and engulfing Mercury and Venus.
The star Kepler-56 is becoming a red giant star as well. It already has ballooned out to four times the Sun`s size. As it ages, it will continue to expand outward. Not only will the star grow larger, but its tides will get stronger, dragging its planets inward to their eventual doom.

Kepler-56b orbits its host star once every 10.5 days, while Kepler-56c orbits every 21.4 days. Both of them are much closer to their star than Mercury is to the Sun. As a result, they will meet their fate much faster.
Li and her collaborators calculated the evolution of both the star`s size (using the publicly available MESA code) and the planets` orbits to predict when the planets will be destroyed.

Even before they vanish, the two planets will be subjected to immense heating from the steadily growing star. Their atmospheres will begin to boil off, and the planets themselves will be stretched into egg shapes by stellar tides.

The only survivor in the system will be Kepler-56d, a gas giant planet circling in a 3.3-Earth-year orbit. It will watch from a safe distance as its two sibling worlds meet their demise.