# # Program information file # PROGRAM_ID 2021A036 PROGRAM_TITLE Spectroscopic Monitoring of two Eruptive YSOs PROGRAM_INV1 Klaus Hodapp PROGRAM_INV2 PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG Do stars accumulate most of their mass during outburst events, or in the longer quiescent phases between outbursts? Only a few dozen bona fide cases of accretion outbursts in YSOs, i.e., FUor and EXor events, have been observed historically, plus a small number of peculiar cases that fall outside of these classes. We now have unprecedented opportunities for answering this question by detailed studies of all the YSO outbursts found in ongoing all-sky monitoring missions such as Gaia. We are currently following two on-going outburst of eruptive YSOs: ESO-Ha 99 = IRAS08370-4030 from Gaia alert Gaia2018dvz and the recently discovered Gaia20eae, both examples of broadly the EXor class of outburstwith an emission line spectrum. Our goal for ESO-Ha 99 is to study the further evolution of the spectrum with SPEX and to observe the velocity profile of prominent emission lines at high spectral resolutions with iSHELL. For the recently discovered Gaia20eae, for which we only have one optical spectrum taken in Sept. 2020 at this time, we want to study the evolution of what is at present an emission line spectrum as the outburst evolves. PROGRAM_ABSTRACT_END