The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars

Yong Hee Lee, Doug Johnstone, Jeong Eun Lee*, Gregory Herczeg, Steve Mairs, Carlos Contreras-Peña, Jennifer Hatchell, Tim Naylor, Graham S. Bell, Tyler L. Bourke, Colton Broughton, Logan Francis, Aashish Gupta, Daniel Harsono, Sheng Yuan Liu, Geumsook Park, Spencer Plovie, Gerald H. Moriarty-Schieven, Aleks Scholz, Tanvi SharmaPaula Stella Teixeira, Yao Te Wang, Yuri Aikawa, Geoffrey C. Bower, Huei Ru Vivien Chen, Jaehan Bae, Giseon Baek, Scott Chapman, Wen Ping Chen, Fujun Du, Somnath Dutta, Jan Forbrich, Zhen Guo, Shu Ichiro Inutsuka, Miju Kang, Helen Kirk, Yi Jehng Kuan, Woojin Kwon, Shih Ping Lai, Bhavana Lalchand, James M.M. Lane, Chin Fei Lee, Tie Liu, Oscar Morata, Samuel Pearson, Andy Pon, Dipen Sahu, Hsien Shang, Dimitris Stamatellos, Shih Yun Tang, Ziyan Xu, Hyunju Yoo, Jonathan M.C. Rawlings

*此作品的通信作者

研究成果: 雜誌貢獻回顧評介論文同行評審

5 引文 斯高帕斯(Scopus)

摘要

We present the four-year survey results of monthly submillimeter monitoring of eight nearby (<500 pc) star-forming regions by the JCMT Transient Survey. We apply the Lomb-Scargle Periodogram technique to search for and characterize variability on 295 submillimeter peaks brighter than 0.14 Jy beam-1, including 22 disk sources (Class II), 83 protostars (Class 0/I), and 190 starless sources. We uncover 18 secular variables, all of them protostars. No single-epoch burst or drop events and no inherently stochastic sources are observed. We classify the secular variables by their timescales into three groups: Periodic, Curved, and Linear. For the Curved and Periodic cases, the detectable fractional amplitude, with respect to mean peak brightness, is ∼4% for sources brighter than ∼0.5 Jy beam-1. Limiting our sample to only these bright sources, the observed variable fraction is 37% (16 out of 43). Considering source evolution, we find a similar fraction of bright variables for both Class 0 and Class I. Using an empirically motivated conversion from submillimeter variability to variation in mass accretion rate, six sources (7% of our full sample) are predicted to have years-long accretion events during which the excess mass accreted reaches more than 40% above the total quiescently accreted mass: two previously known eruptive Class I sources, V1647 Ori and EC 53 (V371 Ser), and four Class 0 sources, HOPS 356, HOPS 373, HOPS 383, and West 40. Considering the full protostellar ensemble, the importance of episodic accretion on few years timescale is negligible - only a few percent of the assembled mass. However, given that this accretion is dominated by events on the order of the observing time window, it remains uncertain as to whether the importance of episodic events will continue to rise with decades-long monitoring.

原文英語
文章編號119
期刊Astrophysical Journal
920
發行號2
DOIs
出版狀態已發佈 - 2021 10月 20

ASJC Scopus subject areas

  • 天文和天體物理學
  • 空間與行星科學

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