Title：Stellar Mass Assembly and the JCMT-Transient Survey: Searching for sub-mm variability of protostars

Speaker：Gregory Herczeg (KIAA/Peking University)

Time: Sep. 23th, Monday, 9:30 am

Tencent Meeting：829-686-971

Location: Large meeting room, 3rd floor

Abstract：

Variable accretion in young stellar objects reveals itself photometrically and spectroscopically over a continuum of timescales and amplitudes.  The most dramatic accretion bursts, FU Ori outbursts, affect the chemical evolution of the envelope and protoplanetary disk, but their role in stellar mass assembly is still uncertain because these rare events were only discovered at optical wavelengths, where growing protostars are not detectable.  Our East Asia Observatory JCMT/SCUBA2 sub-mm monitoring program, the first large sub-mm variability program, is surveying accretion variability of protostars in fourteen star-forming regions.  We have discovered several strong and modest variables, with some variability detected in half of the brightest sources.  We have also detected what may be the brightest radio flare ever detected from a cool star.  The sub-mm program is supplemented by discoveries at other wavelengths, especially in the mid-IR from NEOWISE.  I will also discuss opportunities and challenges in achieving more ambitious science goals in with future facilities.

CV：Gregory Herczeg is a Professor and Associate Director of Science at the Kavli Institute for Astronomy and Astrophysics at Peking University, where he has worked since 2011.  He also serves as a Science Editor for AAS Journals and was the Chair of the Science Advisory Committee for the Thirty Meter Telescope from 2020-2022.  He received his PhD from University of Colorado in 2005 under the supervision of Jeff Linsky, and subsequently worked as a postdoc at Caltech with Lynne Hillenbrand and at Max Planck Institute for Extraterrestrial Physics with Ewine van Dishoeck.  He is an expert in observational studies of star and planet formation, with over 250 co-authored publications.