Refining the Radii of Exoplanet Host Stars

University Of Hawaii, Honolulu

Investigators

Abstract

The Kepler space mission has found thousands of planets that pass in front of -- or transit -- the stars that they orbit, as seen from Earth. We can, however, only learn about the properties of these exoplanets (such as size) as they are compared to the stars that they orbit. It is therefore very important that we measure and understand the properties of these stars correctly. The methods that astronomers have used to study these properties of stars can lead to levels of error that affect our information about the exoplanets. This project combines data from the Gaia spacecraft mission with data taken from telescopes in Hawaii to make the first uniform characterization of the stars like the Sun with orbiting planets. The results of this study will then improve our studies of the exoplanets themselves. This project serves the national interest by promoting the progress of our understanding of exoplanets and the potential for life beyond Earth. University students will work on this research. In addition, the Principal Investigator will make public presentations about how the research done on ground-based telescopes in Hawaii helps to study the data acquired from space-based missions such as Kepler and Gaia. Current interpretation of the exoplanet population critically hinges on the ability to characterize their host stars. Traditional techniques used to determine stellar properties are uncertain for solar-type stars. The radius precision for over 99% of all Kepler exoplanets is limited by the uncertainties in the radii of the host stars, which are on average between 20-30%. This project will derive the first homogeneous and accurate characterization of all Kepler exoplanet host stars and the Kepler parent sample. These properties will be used to explore the habitability and compositions of small Kepler exoplanets as well as provide first insights into the occurrence rates of exoplanets as a function of stellar evolution.