# # Program information file # PROGRAM_ID 2022A060 PROGRAM_TITLE Infrared spectroscopy to support an optical interferometric study of symbiotic stars PROGRAM_INV1 Thomas Gaudin PROGRAM_INV2 Ryan Norris PROGRAM_INV3 Michelle Creech-Eakman PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Symbiotic stars are a type of wide interacting binary consisting of a cool giant and a hot companion, typically a white dwarf. These systems are characterized by a long orbital period, wide binary separation, and a dense circumstellar medium produced by mass transfer from giant to companion. The nature and mechanisms of mass transfer within symbiotic systems are currently poorly understood. Research shows that optical interferometry can be used in conjunction with NASA IRTF in order to investigate the mass transfer process and constrain mass transfer models in symbiotic stars. Optical interferometry imaging performed with the CHARA Array allows for the measurement of the giant's radius and its Roche filling factor. Spectroscopic data is used to determine the fundamental stellar parameters of the giant and to characterize the circumstellar material so that it can be calibrated out of the optical interferometry data. We seek to observe six nearby symbiotic star systems: CQ Dra, CH Cyg, T CrB, NQ Gem, V934 Her, and V1472 Aql. In order to support our optical interferometry observations, we are requesting 2 nights using SpeX to gather near-contemporaneous infrared spectra of these targets. The CHARA observations will take place in March and June, so we request one night in each month during which we will observe 2-4 stars. Our proposed methodology is to gather high resolution [R~2500] SXD and LXD-long spectra using the 0.3'x15' slit. We estimate that we can achieve our desired SNR of 25 in 1 hour and 45 minutes even accounting for the amount of time it takes to observe using LXD. LXD observations are necessary in order to characterize the infrared excess that is expected to exist at longer wavelengths. PROGRAM_ABSTRACT_END