Issue |
A&A
Volume 665, September 2022
|
|
---|---|---|
Article Number | A147 | |
Number of page(s) | 22 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361/202243599 | |
Published online | 21 September 2022 |
The magneto-rotational instability in massive stars
1
Departament d’Astronomia i Astrofísica, Universitat de València, 46100 Burjassot, Spain
e-mail: adam.griffiths@uv.es
2
Geneva Observatory, University of Geneva, Chemin Pegasi 51, 1290 Sauverny, Switzerland
3
Observatori Astronòmic, Universitat de València, 46980 Paterna, Spain
Received:
21
March
2022
Accepted:
19
July
2022
Context. The magneto-rotational instability (MRI) has been proposed as a mechanism to transport angular momentum (AM) and chemical elements in theoretical stellar models.
Aims. Using as a prototype a massive star of 15 M⊙ with solar metallicity, we explore the effects of the MRI on the evolution of massive stars.
Methods. We used the Geneva Stellar Evolution Code to simulate the evolution of various models, up to the end of oxygen burning, including the MRI through effective, one-dimensional, diffusion coefficients. We consider different trigger conditions (depending on the weighting of chemical gradients through an arbitrary but commonly used factor) and different treatments of meridional circulation as either advective or diffusive. We also compare the MRI with the Tayler-Spruit (TS) dynamo in models that included both instabilities.
Results. The MRI triggers throughout stellar evolution. Its activation is highly sensitive to the treatment of meridional circulation and the existence of chemical gradients. The MRI is very efficient at transporting both matter and AM, leading to noticeable differences in rotation rates and chemical structure, which may be observable in young main sequence stars. While the TS dynamo is the dominant mechanism for transferring AM, the MRI remains relevant in models where both instabilities are included. Extrapolation of our results suggests that models that include the MRI tend to develop more compact cores, which likely produce failed explosions and black holes, than models where only the TS dynamo is included (where explosions and neutron stars may be more frequent).
Conclusions. The MRI can be an important factor in massive star evolution but is very sensitive to the implementation of other processes in the model. The transport of AM and chemical elements due to the MRI alters the rotation rates and the chemical makeup of the star from the core to the surface and may change the explodability properties of massive stars.
Key words: instabilities / stars: abundances / stars: rotation / stars: magnetic field / stars: evolution
© A. Griffiths et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
This article is published in open access under the Subscribe-to-Open model. Subscribe to A&A to support open access publication.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.