Credit: @intospace0

TOI 813b: Saturn-Sized Exoplanet Found Orbiting Subgiant Star.

Evolved stars are very rare in our solar neighborhood, as the subgiant and giant phases of stellar evolution are short-lived. Consequently, only a few exoplanets are known around such stars.

TOI 813 is a bright subgiant which is in the process of evolving away from the main sequence and onto the red giant phase.

Also known as TIC 55525572, 2MASS J04504658-6054196 and CD-61 970, the star is approximately 3.73 billion years old. It has an estimated mass of 1.3 solar masses and a radius of 1.9 solar radii.

TOI 813b orbits the star once every 84 days at a distance of only 0.4 AU. The planet is about 6.7 times bigger than Earth and 42 times more massive. “TOI 813b is interesting for many reasons,” said Nora Eisner, a Ph.D. student in the Department of Physics at the University of Oxford. “First, because it is orbiting around an evolved, subgiant star. The subgiant phase of a star occurs when a star runs out of its nuclear fuel source and, in a desperate attempt to find another source of energy, expands its outer layers and contracts its core.” “Our Sun has not yet reached this stage of its life — it still has around half of its fuel source left — but it will undoubtedly one day also become a subgiant star.”

Read more: http://www.sci-news.com/astronomy/toi-813b-saturn-sized-exoplanet-found-subgiant-star-07885.html