Differentiating characteristics in exoplanet host stars

With technological advancements now allowing for precise measurements of stars, surveys are discovering thousands of exoplanets—planets outside of our solar system. We now have data on not just the kinematics and stellar chemistry (a star’s chemical makeup and evolutionary stage) of host stars (the stars around which exoplanets orbit) but also on exoplanets’ positions, sizes, and chemical compositions. However, while past studies have explored specific host star trends, no study has comprehensively analyzed how the stellar properties measured across these surveys differ in host stars. This understanding is important for exoplanet studies, as it can help astronomers understand the conditions favorable for exoplanet development and the exoplanets themselves better. In this study, we hypothesized that stellar chemistry, classification, and kinematics would differ significantly between exoplanet host stars and the galactic stellar population, as well as between host star subpopulations based on the type of planet hosted. To test this hypothesis, we analyzed data from recent surveys, including Gaia, the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, the Transiting Exoplanet Survey Satellite (TESS), and the NASA Exoplanet Archive. While we found that stellar chemistry was a significant differentiator between the exoplanet host star and the general population, we could not draw conclusive results about stellar classification or kinematics due to significant bias in TESS’s selection. However, when comparing exoplanet host star subpopulations, we found that both stellar chemistry and kinematics yielded significant differences. These findings can be used to further test planetary formation models and indicate which stars could be more likely to host exoplanets for future exoplanet surveys.