IRTF Data Archive Program Information

# # Program information file # PROGRAM_ID 2021B043 PROGRAM_TITLE The inner disk heating of NEOWISE-selected protostellar variables PROGRAM_INV1 Gregory Herczeg PROGRAM_INV2 Doug Johnstone PROGRAM_INV3 Jeong-Eun Lee PROGRAM_INV4 Carlos Contreras Pena PROGRAM_INV5 Jessy Jose PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG The main phase of stellar growth is expected to occur when a star is deeply embedded. Models of young disks and observations of stellar accretion at later stages of star/disk evolution indicate that large outbursts should play a significant role in the growth of the star, with far-reaching consequences for star and disk evolution. However, most known outbursts are biased to older stages of star/disk evolution, a consequence of transient searches conducted primarily at optical wavelengths. We have found fascinating mid-IR variability in our comprehensive search of NEOWISE observations of a complete, unbiased, and nearby sample of protostars. We propose to obtain IRTF/SpeX spectra of 40 faint protostars and disk sources with large NEOWISE variability to convert mid-IR variability into accretion variability in a large, unbiased sample. These spectra will complement 32 Gemini/GNIRS+F2 spectra already approved [some in-hand] and 16 faint objects proposed for GNIRS in 2021B. The CO bandhead will be used to assess inner disk heating, which will allow us to classify and measure the accretion variability. By characterizing these bursts with near-IR spectroscopy, we will be able to use the variability measures over the complete NEOWISE sample to make powerful and general statistical statements about the role of accretion variability in protostars -- allowing us to finally place empirical quantification of outbursts in the framework of star formation and disk evolution models. PROGRAM_ABSTRACT_END