# # Program information file # PROGRAM_ID 2024A069 PROGRAM_TITLE A Spectroscopic Survey of Class 0 and Deeply Embedded Class I Protostars PROGRAM_INV1 Michael Connelley PROGRAM_INV2 PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG We propose to conduct a near-IR spectroscopic survey of Class 0 and deeply embedded Class I protostars, youngest stars observable in the near-IR. The goal of this project is to determine if we can detect photospheric absorption lines from such young protostar, and to measure their mass accretion rates. While Class 0 objects are usually only visible in the far-IR to millimeter wavelengths, some are just bright enough at K-band to be within reach of SpeX. Recent progress has been made in understanding the physical properties of Class I, II, and III YSOs with a combination of SpeX and iSHELL observation. Now we would like to extend this work to younger objects, with spectra indices higher [and presumably younger] than most previously observed Class I YSOs. For this program we have selected 14targets that are relatively bright [K<15], but with a low bolometric temperature [ < 100 K], and high spectral index [a>1] for most targets. If this program is successful in detecting photospheric lines, then that will enable us to target future observations towards those targets and understand the physical properties of the youngest stars. Measurements of the mass accretion rate will shed light on when young stars are or are not gaining the bulk of their final mass. PROGRAM_ABSTRACT_END