Periodic Eruptive Variability of the Isolated Pre-main-sequence Star V347 Aurigae
Abstract
V347 Aurigae is associated with the small dark cloud L1438 and appears to be an isolated pre-main-sequence star located at distance d ≈ 200 pc. Multi-epoch, archival photometry reveals periodic brightness variations with amplitude V ≈ 2.0 mag occurring on timescales of ∼160 days that have persisted for decades. Regular-cadence, optical imaging of the source with the Zwicky Transient Facility shows that a small reflection nebula illuminated by V347 Aur also fluctuates in brightness, at times fading completely. Multi-epoch, Keck/HIRES data suggests the presence of two distinct spectral components: a prominent emission-line-dominated spectrum with a heavily veiled continuum correlated with the bright photometric state, and an M-type absorption line spectrum associated with quiescence. All spectra exhibit strong Balmer and He I line emission, consistent with accretion, as well as high velocity emission arising from the forbidden transitions of [O I], [N II], and [S II] that are generally associated with collimated jets and disk winds. There is no evidence in existing high-dispersion spectroscopy or high-resolution imaging for binarity of V347 Aur. The repeating outburst events are possibly linked to accretion instabilities induced by an undetected companion or a structure within the circumstellar disk that periodically increases the mass accretion rate. V347 Aur is perhaps analogous to an EXor-type variable, though more regularly recurring.
- Publication:
-
The Astronomical Journal
- Pub Date:
- December 2020
- DOI:
- 10.3847/1538-3881/abbfa2
- arXiv:
- arXiv:2010.02996
- Bibcode:
- 2020AJ....160..278D
- Keywords:
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- Pre-main sequence stars;
- Circumstellar disks;
- T Tauri stars;
- Young stellar objects;
- Accretion;
- Stellar accretion disks;
- 1290;
- 235;
- 1681;
- 1834;
- 14;
- 1579;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in the Astronomical Journal