On the Geometry of the Near-core Magnetic Field in Massive Stars
[1];
[2];
[3];
[4]
- Newcastle University, Newcastle upon Tyne (United Kingdom)
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Newcastle University, Newcastle upon Tyne (United Kingdom); Katholieke Univ. Leuven, Heverlee (Belgium)
- Newcastle University, Newcastle upon Tyne (United Kingdom); Planetary Science Institute, Tucson, AZ (United States)
It is well-known that the cores of massive stars sustain a stellar dynamo with a complex magnetic field configuration. However, the same cannot be said for the field's strength and geometry at the convective–radiative boundary, which are crucial when performing asteroseismic inference. In this Letter, we present 3D magnetohydrodynamic (MHD) simulations of a 7 M⊙ mid-main-sequence star, with particular attention given to the convective–radiative boundary in the near-core region. Our simulations reveal that the toroidal magnetic field is significantly stronger than the poloidal field in this region, contrary to recent assumptions. Moreover, the rotational shear layer, also important for asteroseismic inference, is specifically confined within the extent of the Brunt–Väisälä frequency peak. These results, which are based on the inferred properties of HD 43317, have widespread implications for asteroseismic studies of rotation, mixing, and magnetism in stars. While we expect our results to be broadly applicable across stars with similar Brunt–Väisälä frequency profiles and stellar masses, we also expect the MHD parameters (e.g., Rem) and the initial stellar rotation rate to impact the geometry of the field and differential rotation at the convective–radiative interface.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- European Research Council (ERC); Royal Society University Research Fellowship (URF); Science and Technology Facilities Council (STFC); USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- 89233218CNA000001
- OSTI ID:
- 2483514
- Report Number(s):
- LA-UR--24-25321
- Journal Information:
- The Astrophysical Journal. Letters, Journal Name: The Astrophysical Journal. Letters Journal Issue: 1 Vol. 977; ISSN 2041-8205
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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