# # Program information file # PROGRAM_ID 2024B077 PROGRAM_TITLE Measuring the physical stellar parameters and accretion rates of young stars with planet forming disks PROGRAM_INV1 Ellen Lee PROGRAM_INV2 Michael Connelley PROGRAM_INV3 Christian Flores PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We propose to take SpeX and iSHELL spectra of young stars that are the targets of a complementary proposal for Subaru to perform adaptive optics [AO] observations with their new infrared wavefront sensor. The goal of the Subaru observations is to perform the first near-IR imaging observations of disks around ten early stage and/or low mass stars. The IRTF observations will place the AO images into the broader star formation context. High resolution K-band spectra with iSHELL will measure the temperature, gravity, rotation velocity, veiling disk emission, and stellar magnetic field. The temperature and gravity measurements allow us to infer the mass and age of the central star. Given the temperature and a SpeX SXD spectrum, we can fit the observed continuum with a stellar template to derive the extinction. The SXD spectrum also yields the Br gamma line flux, an important accretion tracer, which when combined with extinction, stellar mass, and radius of the star enables us to measure the accretion rate. The key outputs of this program are the stellar age, stellar mass, extinction, and mass accretion rates, for each star individually. Knowing these values are key to interpreting the Subaru AO images to gain insight on the planet forming process. PROGRAM_ABSTRACT_END