Are Exoplanet properties determined by the host star?

The short answer is yes. With the latest Kepler Data release DR25 we now have the largest sample of exoplanet candidates with uniformly determined stellar and planetary properties. Using detailed mathematical prescriptions, we present an unbiased view of the population of planets in the Kepler field by calculating the occurrence rate: ‘ the likelihood of detecting a planet around a star’. Since we account for all the observational biases and selection effects while calculating the occurrence rate of planets, our results must represent the true demographics of the planets and their correlations with the host star properties. In this study, we examine planets orbiting main sequence stars with orbital periods less than a year. We studied various correlations between the observed properties of the planets (radius, mass & orbital period) and their host stars properties (Teff & metallicity). We will show  that the radius (or mass) of the exoplanet is tightly correlated with the  spectral type of the host star and, therefore, with the mass of the host star : the more massive the star the higher the occurrence rate of giant planets around them; conversely, the occurrence rate of small planets is higher around low mass stars.  We also examined the relationship between planet radius or mass and the metallicity of the host star. We found that the metallicity of the host star increases as the radius or mass of the planets increases. Interestingly, for planets with a mass greater than 4.4 M_Jupiter, the trend is reversed: host star metallicity drops with increasing planetary mass. I will discuss these results in the context of star and planet formation theories. Towards the end of the talk, I will discuss some of the future projects we plan to undertake on exoplanets.