TESS's NASA satellite or extrasolar transit satellite made another intriguing discovery. This time, there is a planet somewhere where it should not be, right in the middle of an area where each planet should have been destroyed by its star.
Star HD 203949 is 257 light-years away and is a giant K2-type star slightly cooler than our sun. Traveling around this star is the large planet HD 203949b, which is 8.2 times the mass of Jupiter and in a 1
So far, so typical. But there's something weird about HD 203949b, because it should have been swallowed by its star long ago. The boundaries of a star, called its shell, expand and shrink over time. When giant star HD 203949 was younger in its red giant phase, its shell had to cover the planet and destroy it – and yet the planet is still there.
Researchers explored this mystery more closely using computer simulations. They came up with the theory that the planet must have moved farther from the star and approach it over time.
"We have determined how this planet could reach its present location and do so regardless of whether the planet had to survive being absorbed in the star giant shell by the red giant," co-author Dr. Dimitri Veras explained in a statement. "Work sheds new light on the viability of planets when their parent stars begin to die, and may even reveal new aspects of tidal physics."
This discovery of a planet shifting its orbit over time shows how complex the relationships in within the planet systems can be. "This study is a perfect demonstration of how stellar and exoplanetary astrophysics are related," said the same author, Dr. Vardan Adibekyan, in the same statement. "Stellar analysis seems to suggest that HD 203949 is too advanced to still host a planet for such a short orbital distance, while from exoplanet analysis we know that the planet is there."
"The solution to this scientific dilemma is hidden in the simple fact that stars and their planets not only form but evolve together, ”continued Dr. Adibekian. "In this particular case, the planet was able to avoid being absorbed."
The results are published in the Astrophysical Journal.