Global 3D simulations of convection and dynamos in Red Giants
Abstract
Understanding the internal dynamics of red giants is essential for studying angular momentum transport and magnetic field generation during stellar evolution. We present three-dimensional magnetohydrodynamic simulations of a 1M⊙ red giant at the bottom of the red giant branch using a star-in-a-box setup with the Pencil Code, together with ongoing efforts to refine the numerical model. By varying the rotation rate, we explore different Rossby numbers and identify systematic changes in the convective dynamics and large-scale flows. As the rotation increases, convective motions become more anisotropic, showing clear signatures of rotational constraint and a shift in the dominant convective scales. These changes are accompanied by variations in the differential rotation profile, reflecting the redistribution of angular momentum within the convective envelope. The impact of rotation is also evident in the growth rate and saturation level of the magnetic field, indicating a strong dependence of dynamo efficiency on the underlying flow structure. Together, these results highlight the interplay between convection, rotation, and large-scale flows in shaping magnetic activity in red giant stars.
Versions
Related
- Global solar compressible convection simulations on non-Cartesian mappings
- Global solar compressible convection simulations on non-Cartesian mappings
- Regime transitions of dynamos driven by fingering double-diffusive convection
- Grand minima and intermittency in near-critical convection-driven dynamos
- EPRV asteroseismology of the K dwarfs GJ 570 A and GJ 783 A with ESPRESSO. Empirical mode-amplitude scaling in tension with 3D convection simulations
BibTeX
@misc{ortizrodriguez2026global,
title = {{Global 3D simulations of convection and dynamos in Red Giants}},
author = {Carolina Ortiz-Rodríguez and Petri Käpylä and Juan Pablo Hidalgo and Dominik Schleicher and Robi Banerjee},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07839},
eprint = {2609.07839},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07839},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Global 3D simulations of convection and dynamos in Red Giants
AU - Carolina Ortiz-Rodríguez
AU - Petri Käpylä
AU - Juan Pablo Hidalgo
AU - Dominik Schleicher
AU - Robi Banerjee
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07839
UR - https://arxiv.org/abs/2609.07839
AB - Understanding the internal dynamics of red giants is essential for studying angular momentum transport and magnetic field generation during stellar evolution. We present three-dimensional magnetohydrodynamic simulations of a 1M_⊙ red giant at the bottom of the red giant branch using a star-in-a-box setup with the Pencil Code, together with ongoing efforts to refine the numerical model. By varying the rotation rate, we explore different Rossby numbers and identify systematic changes in the convective dynamics and large-scale flows. As the rotation increases, convective motions become more anisotropic, showing clear signatures of rotational constraint and a shift in the dominant convective scales. These changes are accompanied by variations in the differential rotation profile, reflecting the redistribution of angular momentum within the convective envelope. The impact of rotation is also evident in the growth rate and saturation level of the magnetic field, indicating a strong dependence of dynamo efficiency on the underlying flow structure. Together, these results highlight the interplay between convection, rotation, and large-scale flows in shaping magnetic activity in red giant stars.
ER -