Episodic accretion and mergers during growth of massive protostars

Autor(en)

Vardan Elbakyan, Sergei Nayakshin, Dominique M.A. Meyer, Eduard I. Vorobyov

Abstrakt

3D simulations of high mass young stellar object (HMYSO) growth show that their circumstellar discs fragment on to multiple self-gravitating objects. Accretion of these by HMYSO may explain episodic accretion bursts discovered recently. We post-process results of a previous 3D simulation of a HMYSO disc with a 1D code that resolves the disc and object dynamics down to the stellar surface. We find that burst-like deposition of material into the inner disc seen in 3D simulations by itself does not always signify powerful accretion bursts. Only high density post-collapse clumps crossing the inner computational boundary may result in observable bursts. The rich physics of the inner disc has a significant impact on the expected accretion bursts: (1) in the standard turbulent viscosity discs, migrating objects can stall at a migration trap at the distance of a few au from the star. However, in discs powered by magnetized winds, the objects are able to cross the trap and produce bursts akin to those observed so far. (2) Migrating objects may interact with and modify the thermal (hydrogen ionization) instability of the inner disc, which can be responsible for longer duration and lower luminosity bursts in HMYSOs. (3) If the central star is bloated to a fraction of an au by a previous episode of high accretion rate, or if the migrating object is particularly dense, a merger rather than a disc-mediated accretion burst results; (4) Object disruption bursts may be super-Eddington, leading to episodic feedback on HMYSO surroundings via powerful outflows.

Organisation(en)

Institut für Astrophysik

Externe Organisation(en)

University of Leicester, Russian Academy of Sciences, Universität Potsdam

Journal

Monthly Notices of the Royal Astronomical Society

Band

518

Seiten

791-809

Anzahl der Seiten

19

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stac3115

Publikationsdatum

01-2023

Peer-reviewed

Ja

ÖFOS 2012

103003 Astronomie, 103004 Astrophysik

Schlagwörter

ASJC Scopus Sachgebiete

Astronomy and Astrophysics, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/58ca82e1-7d1a-4be2-a46d-a43a1e52e29a