The Last Stages of Accretion in T Tauri Stars: Insights from Very Low Accretors

Wednesday, 21 November 2018 8 a.m. — 9 a.m. MST

AURA Lecture Hall

NOIRLab South Colloquia
THANAWUTH THANATHIBODEE (University of Michigan and NOAO South Visiting Graduate Student)

Mass accretion is a key parameter for understanding the evolution of young stars, their surrounding protoplanetary disks, and the interaction between them. In low-mass pre-main sequence stars (T Tauri stars; TTS), accretion from the inner region of the protoplanetary disk onto the central star follows the magnetospheric accretion paradigm, according to which the matter flows onto the star along the stellar magnetic field lines. Signatures of magnetospheric accretion have been observed, and numerical simulations have been successful in explaining the overall physical processes that take place. Studies of young stars at different ages show that accretion rate decreases with time and stops at around 5-10 Myr. Nevertheless, it is still unclear what physical processes govern accretion at the last stages, and how accretion stops. Here I will outline our spectroscopic survey to search and characterize weakly accreting TTSs in the 5-10 Myr Orion OB1a and OB1b sub-association. I will also present the results for the first low accretors identified in our study, and their implications for the studies of accretion in the low accretion regime.