# # Program information file # PROGRAM_ID 2022A083 PROGRAM_TITLE Determining stellar embryo properties from present day observations of young stars PROGRAM_INV1 Christian Flores PROGRAM_INV2 Michael Connelley PROGRAM_INV3 Jonathan Williams PROGRAM_INV4 Greg Doppmann PROGRAM_INV5 Nagayoshi Ohashi PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Every star begins its life in the densest parts of a cloud core. Due to the immense amount of material and extinction in these regions, the first stages of stellar evolution are elusive to observations at most wavelengths. For this reason, studies of stellar embryos have been mostly relegated to theoretical and computational frameworks. To date, little to no observational constraints exist on the time it takes to assemble a stellar embryo. This proposal seeks to produce the first observational measurements of the masses and ages of stellar embryos. Infrared spectroscopic observations are key to achieving our goal since they can be used to derive masses, ages, and mass accretion rates of young stellar sources. As explained in detail in the main text, we only require these three quantities to measure masses and ages of stellar embryos. Ages of young stars can be obtained through detailed modeling of spectroscopic observations. Mass accretion rates will be calculated from the Br gamma line at 2.16 microns and stellar masses will be obtained from ALMA gas data through our collaborations. Our proposed research will respond to the long-standing questions of how long does it take a stellar embryo to assemble and how massive can these pre-stellar objects be. To carry out our research, we propose iSHELL K-band and SpeX SXD mode observations of a small sample of young stars. Because we need extreme precision in our gravity and mass accretion measurements, we require signal-to-noise ratios of at least S/N=150 for all the observations in our sample. PROGRAM_ABSTRACT_END