Reverse population sythesis for observed planets around evolved stars
With the growing number of exoplanets detected around evolved stars, it becomes evident that the planet population around giant stars possesses different properties than the population around main-sequence stars, especially regarding the period distribution.
We investigate the origin of these differences by studying the effect of stellar post-main-sequence evolution on the orbital architecture of the planetary systems detected around evolved stars within our RV survey of G and K giants (Reffert et al. 2015). We use evolutionary tracks to reconstruct the host stars' past evolution and simulate the combined effects of tidally induced orbital decay and mass loss induced orbital expansion on the semi-major axes and eccentricities of the observed planets.
Running our simulations backwards in time allows us to synthesize the planet population as it was on the main-sequence and to compare it to the observed planet population around less massive main-sequence stars.