EAPSI: Correlating Planet Discoveries to a Bias in Binary Star Orientation with New Large Data Surveys

Grieves Nolan S, Gainesville FL

Investigators

Abstract

This project will test for an alignment in the orbital orientation of binary stars, specifically with respect to the Galactic disk, a claim made by several previous studies dating back to the 1830s. However, even recent studies have not had sufficient evidence to fully support this claim due to a lack of data and statistical significance. Unlike previous studies, which relied on stars being relatively close in proximity to the Sun to determine orbital orientations, this project will use two large sample planet surveys with different sky orientations in order to determine binary orbital orientation. This research will be conducted at Nanjing University, one of China?s premier Astronomy programs, with Dr. Jiwei Xie. Dr. Xie specializes in binary star systems and planet formation around these systems. He has unique expertise for this project including experience with both of these planet surveys. The project results will not only have significant implications on star formation theory, but will also affect exoplanet characterization, including the occurrence rate of Earth-like planets in the Milky Way Galaxy. Although previous studies found evidence for a bias in binary star orbital planes with respect to the galactic disk, these findings are based on only a small number of systems relatively close to the solar system. This project?s technique does not rely on close proximity and will allow a significantly larger sample to be analyzed. This research will develop a model to compare the all-sky radial velocity survey MARVELS and the transit survey Kepler, which is positioned near the Galactic plane. The project will develop code to build several simulated binary populations and models to statistically compare them to the real observations of both surveys. The results will be analyzed to determine an orientation bias and the implications it has on the field of Astronomy including factors in planet occurrence rates. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.