How do stars gain their mass? A JCMT/SCUBA-2 transient survey of protostars in nearby star-forming regions

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, Ramprasad Rao, Helen Kirk, Satoko Takahashi, Oscar MorataKevin Lacaille, James Lane, Andy Pon, Zhaohuan Zhu, Aleks Scholz, Manash R. Samal, Graham S. Bell, Sarah Graves, Elisa 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, Feng Long, A. Ran Lyo, Lei Qian, Peter Scicluna, Archana Soam, Dimitris Stamatellos, Chin Fei Lee, Shigehisa Takakuwa, Ya Wen Tang, Hongchi Wang, Yiren Wang

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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 deg2 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.

Original languageEnglish
Article numberaa8b62
JournalAstrophysical Journal
Volume849
Issue number1
DOIs
Publication statusPublished - 2017 Nov 1

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Keywords

  • Herbig Ae/Be
  • Stars: formation
  • Stars: protostars
  • Stars: variables: T Tauri
  • Submillimeter: stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Herczeg, G. J., Johnstone, D., Mairs, S., Hatchell, J., Lee, J. E., Bower, G. C., Chen, H. R. V., Aikawa, Y., Yoo, H., Kang, S. J., Kang, M., Chen, W. P., Williams, J. P., Bae, J., Dunham, M. M., Vorobyov, E. I., Rao, R., Kirk, H., Takahashi, S., ... Wang, Y. (2017). How do stars gain their mass? A JCMT/SCUBA-2 transient survey of protostars in nearby star-forming regions. Astrophysical Journal, 849(1), [aa8b62]. https://doi.org/10.3847/1538-4357/aa8b62