Zhen Guo
Philip Lucas
Carlos Contreras Peña
Leigh Smith
Calum Morris
The VVV team
2021-02-24
<p>The decade-long Vista Variables in the Via Lactea (VVV) survey has detected numerous highly variable young stellar objects (YSOs). We present a study of 61 highly variable VVV YSOs combining near-infrared spectra from Magellan and VLT with VVV and NEOWISE light curves to investigate the physical mechanisms behind eruptive events. Most sources are spectroscopically confirmed as eruptive variables (typically Class I YSOs) but variable extinction is also seen. Among them, <strong>magnetically controlled accretion</strong>, identified by HI recombination emission, is observed in <strong>47 YSOs</strong>. Boundary layer accretion, associated with FU Ori-like outbursts identified by CO overtone and H<sub>2</sub>O absorption, is observed only in longer duration events (> 5 yr total duration). However, even in long-duration events, the <strong>magnetically controlled accretion mode predominates</strong>, with amplitudes similar to the boundary layer mode. We find that the ratio of amplitudes in Ks and W2 can distinguish between variable accretion and variable extinction. 13 YSOs are periodic or quasi-periodic variables. We identify examples of<strong> periodic accretors</strong> and extinction-driven periodicity among them (with periods up to 5 yr) though more data are needed to classify some cases. The data suggest that dynamic interactions with a companion may control the accretion rate in a substantial proportion of eruptive systems.</p>
https://doi.org/10.5281/zenodo.4560381
oai:zenodo.org:4560381
Zenodo
https://zenodo.org/communities/coolstars20half
https://doi.org/10.5281/zenodo.4560380
info:eu-repo/semantics/openAccess
Creative Commons Attribution 4.0 International
https://creativecommons.org/licenses/by/4.0/legalcode
pre-main sequence
variable stars
young stellar objects
young stars
accretion
Analysis of physical processes in eruptive YSOs with near infrared spectra and multi-wavelength light curves
info:eu-repo/semantics/conferencePoster