English
 
User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Long-term evolution of a magnetic massive merger product

MPS-Authors
/persons/resource/persons4732

Pakmor,  R.
Stellar Astrophysics, MPI for Astrophysics, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Schneider, F. R. N., Ohlmann, S. T., Podsiadlowski, P., Röpke, F., Balbus, S. A., & Pakmor, R. (2020). Long-term evolution of a magnetic massive merger product. Monthly Notices of the Royal Astronomical Society, 495(3), 2796-2812. doi:10.1093/mnras/staa1326.


Cite as: http://hdl.handle.net/21.11116/0000-0007-0E0D-D
Abstract
About 10 per cent of stars more massive than ≈1.5M have strong, large-scale surface magnetic fields and are being discussed as progenitors of highly magnetic white dwarfs and magnetars. The origin of these fields remains uncertain. Recent three-dimensional (3D) magnetohydrodynamical simulations have shown that strong magnetic fields can be generated in the merger of two massive stars. Here, we follow the long-term evolution of such a 3D merger product in a 1D stellar evolution code. During a thermal relaxation phase after the coalescence, the merger product reaches critical surface rotation, sheds mass and then spins down primarily because of internal mass readjustments. The spin of the merger product after thermal relaxation is mainly set by the co-evolution of the star–torus structure left after coalescence. This evolution is still uncertain, so we also consider magnetic braking and other angular momentum-gain and -loss mechanisms that may influence the final spin of the merged star. Because of core compression and mixing of carbon and nitrogen in the merger, enhanced nuclear burning drives a transient convective core that greatly contributes to the rejuvenation of the star. Once the merger product relaxed back to the main sequence, it continues its evolution similar to that of a genuine single star of comparable mass. It is a slow rotator that matches the magnetic blue straggler τ Sco. Our results show that merging is a promising mechanism to explain some magnetic massive stars and it may also be key to understand the origin of the strong magnetic fields of highly magnetic white dwarfs and magnetars.