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2020天文年會
中研院天文所 國際會議廳

論文摘要

The JCMT/SCUBA-2 Transient Survey for the detection of accretion variability and transient phenomena

[ Oral ]

Bhavana Lalchand (National Central University, Taiwan); Wen-Ping Chen (National Central University, Taiwan); Steve Mairs (East Asian Observatory, Hilo, USA); Gregory J. Herczeg (Kavli Institute for Astronomy and Astrophysics, Peking University, People's Republic of China); Doug Johnstone (NRC Herzberg Astronomy and Astrophysics, & Department of Physics and Astronomy, University of Victoria, Canada)

Observations of temporal brightness and variability of stars provide physical insights to diagnose the stellar structure, e.g. the convective/dynamo mechanism. During the earliest phase of stellar assembly, when a protostar is vigorously accreting from circumstellar material, sporadic brightening events led by outflows (flares) are expected. Owing to the enshrouding dusty circumstellar material, optical/infrared detection is ineffective in detecting such protostellar flares. Here we report a dedicated program to monitor, on a monthly cadence to measure the accretion variability of protostellar candidates in star-forming regions with the James Clerk Maxwell Telescope (JCMT) using the SCUBA-2 bolometer array. This is the first time-domain submillimeter program, being carried out since 2015 for eight nearby star-forming regions such as IC348, NGC1333, Ophiuchus Core, among others. The program has successfully detected known 182 protostars (Class 0) and 800 disk sources (T-Tauri stars). A particularly important event in the stellar evolution is the emergence of flares during various magnetic reconnection led gyro-synchrotron radiation. We report the recent observation of such an extraordinary sub-mm flare by a T-Tauri binary JW566. We will present the detection algorithm for such events while also showing possible other candidate flaring events. Further, we will show the reconciliation of our observational statistical models with theoretical predictions.