A planet orbiting inside of a star.

Most of stars pass via the state of red giant during their evolution partially engulfing their planetary systems. We investigate theoretically and computationally how a planet moves inside of such star and how quickly it heats up. Surprisingly, our modeling shows that a planet does not quickly disintegrate inside of a red giant star nor does it even change its orbit quickly -- in some cases a planet continues to orbit below a photosphere of a red giant star for thousands of years, and in some other cases - for millions of years (!).