Burst occurrence in young massive stellar objects

D. M.-A. Meyer (1), E. I. Vorobyov (2,3) , V. G. Elbakyan (3) , B. Stecklum (4) , J. Eislöffel (4) and A. M. Sobolev (5)

(1) Astrophysics Group, School of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, United Kingdom
(2) Department of Astrophysics, The University of Vienna, Vienna, A-1180, Austria
(3) Research Institute of Physics, Southern Federal University, Stachki 194, Rostov-on-Don, 344090, Russia
(4) Thüringer Landessternwarte Tautenburg, Sternwarte 5, D-07778 Tautenburg, Germany
(5) Astronomical Observatory, Institute for Natural Sciences and Mathematics, Ural Federal University, Ekaterinburg, 620000, Russian Federation

Episodic accretion-driven outbursts are an extreme manifestation of accretion variability. It has been proposed that the development of gravitational instabilities in the proto-circumstellar medium of massive young stellar objects (MYSOs) can lead to such luminous bursts, when clumps of fragmented accretion discs migrate onto the star. We simulate the early evolution of MYSOs formed by the gravitational collapse of rotating 100 M pre-stellar cores and analyze the characteristics of the bursts that episodically accompany their strongly time-variable protostellar lightcurve. We predict that MYSOs spend ≈ 10 3 yr (≈ 1.7%) of their modelled early 60 kyr experiencing eruptive phases, during which the peak luminosity exceeds the quiescent
pre-burst values by factors from 2.5 to more than 40. Throughout these short time periods, they can acquire a substential fraction (up to ≈ 50 %) of their zero-age-main sequence mass. Our findings show that fainter bursts are more common than brighter ones. We discuss our results in the context of the known bursting MYSOs, e.g. NGC6334I-MM1 and S255IR-NIRS3, and propose that these monitored bursts are part of a long-time ongoing series of eruptions, which might, in the future, be followed by other luminous flares.

Reference: Accepted at MNRAS
Status: Manuscript has been accepted

Weblink: https://arxiv.org/abs/1811.00574


Email: dmameyer.astro@gmail.com