تقرير
The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars
| العنوان: | The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars |
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| المؤلفون: | Lee, Yong-Hee, Johnstone, Doug, Lee, Jeong-Eun, Herczeg, Gregory, Mairs, Steve, Contreras-Peña, Carlos, Hatchell, Jennifer, Naylor, Tim, Bell, Graham S., Bourke, Tyler L., Broughton, Colton, Francis, Logan, Gupta, Aashish, Harsono, Daniel, Liu, Sheng-Yuan, Park, Geumsook, Plovie, Spencer, Moriarty-Schieven, Gerald H., Scholz, Aleks, Sharma, Tanvi, Teixeira, Paula Stella, Wang, Yao-Te, Aikawa, Yuri, Bower, Geoffrey C., Chen, Huei-Ru Vivien, Bae, Jaehan, Baek, Giseon, Chapman, Scott, Chen, Wen Ping, Du, Fujun, Dutta, Somnath, Forbrich, Jan, Guo, Zhen, Inutsuka, Shu-ichiro, Kang, Miju, Kirk, Helen, Kuan, Yi-Jehng, Kwon, Woojin, Lai, Shih-Ping, Lalchand, Bhavana, Lane, James M. M., Lee, Chin-Fei, Liu, Tie, Morata, Oscar, Pearson, Samuel, Pon, Andy, Sahu, Dipen, Shang, Hsien, Stamatellos, Dimitris, Tang, Shih-Yun, Xu, Ziyan, Yoo, Hyunju |
| سنة النشر: | 2021 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies |
| الوصف: | 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 $\sim4$ % for sources brighter than $\sim$ 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 of order the observing time-window, it remains uncertain as to whether the importance of episodic events will continue to rise with decades-long monitoring. Comment: Accepted for publication in the Astrophysical Journal |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.3847/1538-4357/ac1679 |
| URL الوصول: | http://arxiv.org/abs/2107.10750 |
| رقم الأكسشن: | edsarx.2107.10750 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.3847/1538-4357/ac1679 |
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