Lee, Y-H;
Johnstone, D;
Lee, J-E;
Herczeg, G;
Mairs, S;
Contreras-Pena, C;
Hatchell, J;
... Rawlings, JMC; + view all
(2021)
The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars.
Astrophysical Journal
, 920
, Article 119. 10.3847/1538-4357/ac1679.
Preview |
Text
Lee_2021_ApJ_920_119.pdf - Published Version Download (2MB) | Preview |
Abstract
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.
| Type: | Article |
|---|---|
| Title: | The JCMT Transient Survey: Four-year Summary of Monitoring the Submillimeter Variability of Protostars |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/ac1679 |
| Publisher version: | https://doi.org/10.3847/1538-4357/ac1679 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Protostars; Young stellar objects; Pre-main-sequence stars; FU Orionis stars; Submillimeter astronomy; Star formation; Variable stars |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10138429 |
Loading...
Loading...Loading...Loading...Archive Staff Only
 |
View Item |
