LEAPS-MPS:High Resolution Studies of Interacting Binaries

New Mexico Institute Of Mining And Technology, Socorro NM

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). Symbiotic stars are a type of interacting binary system consisting of a red giant that donates material to a white dwarf or neutron star companion via winds and/or Roche-lobe overflow. They offer important insights into stellar evolution in binary systems and the formation of binaries containing neutron stars and/or black holes, and are believed to contribute a not- insignificant fraction of Type Ia supernovae, which currently provide our best means of measuring cosmic distances and the acceleration of the universe. Determining the method and rate of mass transfer is key to answering questions about their evolution and role as Type Ia progenitors. The principal investigator (PI) will lead a team of students using optical interferometry to measure precise shapes and radii of the red giant stars in a sample of known symbiotic stars to observe the transfer of mass to the white dwarf/neutron star companion. Few interferometric studies of symbiotic stars have been done to date, and the proposed work promises to make a significant contribution to the field by systematically obtaining some of the highest resolution images of any star (apart from the sun) over a multi-year timeline. The project will provide material for a Master’s Thesis and research mentoring for underserved student populations and will support outreach initiatives to local schools. The PI will use the MIRC-X (H-band and J-band), MYSTIC (K-band), and SPICA (optical) combiners on the Center for High Angular Resolution Astronomy (CHARA) Array to collect optical interferometric data for image reconstruction of these systems. In order to look for evidence of mass transfer, they will need to observe these systems at different orbital positions. As a result, these data will be collected regularly over the course of the grant, with cadence depending on the orbital parameters of each system. Systems with primary stars of angular diameter greater than 2 milli-arcseconds will be used to facilitate imaging and search for elongation due to Roche-lobe overflow. In order to determine the fundamental parameters of the primary and identify the presence of dust, facilities such as SpeX on the NASA InfraRed Telescope Facility (IRTF) will be used to obtain near-infrared spectroscopy. The proposal will use advances in image reconstruction to improve the quality of images produced using the data. New modelling techniques will also be developed to search for elongation and disk formation in the systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.