How Do Stars Gain Their Mass? A JCMT/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions

Author(s)

Gregory J. Herczeg, Doug Johnstone, Steve Mairs, Jennifer Hatchell, Jeong-Eun Lee, Geoffrey C. Bower, Huei-Ru Vivien Chen, Yuri Aikawa, Hyunju Yoo, Sung-Ju Kang, Miju Kang, Wen-Ping Chen, Jonathan P. Williams, Jaehan Bae, Michael M. Dunham, Eduard I. Vorobyov, Zhaohuan Zhu, Ramprasad Rao, Helen Kirk, Satoko Takahashi, Oscar Morata, Kevin Lacaille, James Lane, Andy Pon, Aleks Scholz, Manash R. Samal, Graham S. Bell, Sarah Graves, E'lisa M. Lee, Harriet Parsons, Yuxin He, Jianjun Zhou, Mi-Ryang Kim, Scott Chapman, Emily Drabek-Maunder, Eun Jung Chung, Stewart P. S. Eyres, Jan Forbrich, Lynne A. Hillenbrand, Shu-ichiro Inutsuka, Gwanjeong Kim, Kyoung Hee Kim, Yi-Jehng Kuan, Woojin Kwon, Shih-Ping Lai, Bhavana Lalchand, Chang Won Lee, Chin-Fei Lee, Feng Long, A-Ran Lyo, Lei Qian, Peter Scicluna, Archana Soam, Dimitris Stamatellos, Shigehisa Takakuwa, Ya-Wen Tang, Hongchi Wang, Yiren Wang

Abstract

Most protostars have luminosities that are fainter than expected from steady accretion over the protostellar lifetime. The solution to this problem may lie in episodic mass accretion-prolonged periods of very low accretion punctuated by short bursts of rapid accretion. However, the timescale and amplitude for variability at the protostellar phase is almost entirely unconstrained. In A James Clerk Maxwell Telescope/SCUBA-2 Transient Survey of Protostars in Nearby Star-forming Regions, we are monitoring monthly with SCUBA-2 the submillimeter emission in eight fields within nearby (<500 pc) star-forming regions to measure the accretion variability of protostars. The total survey area of ∼1.6 deg

² includes ∼105 peaks with peaks brighter than 0.5 Jy/ beam (43 associated with embedded protostars or disks) and 237 peaks of 0.125-0.5 Jy/beam (50 with embedded protostars or disks). Each field has enough bright peaks for flux calibration relative to other peaks in the same field, which improves upon the nominal flux calibration uncertainties of submillimeter observations to reach a precision of ∼2%-3% rms, and also provides quantified confidence in any measured variability. The timescales and amplitudes of any submillimeter variation will then be converted into variations in accretion rate and subsequently used to infer the physical causes of the variability. This survey is the first dedicated survey for submillimeter variability and complements other transient surveys at optical and near-IR wavelengths, which are not sensitive to accretion variability of deeply embedded protostars.

Organisation(s)

Department of Astrophysics

External organisation(s)

Peking University, National Research Council Canada (NRC-CNRC), University of Victoria, University of Exeter, Kyung Hee University, Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), No. 1, Section 4, Roosevelt Road, National Tsing Hua University, Tokyo Denki University, Chungnam National University (CNU), Korea Astronomy and Space Science Institute, National Central University, University of Hawaii at Manoa, University of Michigan Health System, Central Michigan University, State University of New York, Oswego, State University of New York, Fredonia, Harvard-Smithsonian Center for Astrophysics, University of Nevada, Reno, University of Nevada-Las Vegas, National Taiwan University, Joint ALMA Observatory, National Institutes of Natural Sciences (NINS), National Astronomical Observatory of Japan, University of Western Ontario, Andrews University, East Asian Observatory – Hilo, Hawaii, University of the Chinese Academy of Sciences, Chinese Academy of Sciences (CAS), Chungbuk National University (CBNU), Xiamen University, Cardiff University, University of Central Lancashire, University of Hertfordshire, California Institute of Technology (Caltech), Nagoya City University, Jeju National University, National Taiwan Normal University , Konkuk University, Kagoshima University, Technische Universität Wien, Southern Federal University

Journal

The Astrophysical Journal

Volume

849

No. of pages

14

ISSN

0004-637X

DOI

https://doi.org/10.3847/1538-4357/aa8b62

Publication date

11-2017

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/ca1624ee-4e53-4142-843d-93c5d26c3698