Magnetochronology of solar-type star dynamos

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Hauptverfasser: Noraz, Quentin, Brun, Allan Sacha, Strugarek, Antoine
Format: Preprint
Veröffentlicht: 2024
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author Noraz, Quentin
Brun, Allan Sacha
Strugarek, Antoine
author_facet Noraz, Quentin
Brun, Allan Sacha
Strugarek, Antoine
contents Aims. In this study, we analyse the magnetic field properties of a set of 15 global magnetohydrodynamics (MHD) simulations of solar-type star dynamos conducted using the ASH code. Our objective is to enhance our understanding of these properties by comparing theoretical results to current observations, and to finally provide fresh insights into the field. Methods. We analysed the rotational and magnetic properties as a function of various stellar parameters (mass, age and rotation rate) in a 'Sun in time' approach in our extended set of 3D MHD simulations. To facilitate direct comparisons with stellar magnetism observations using various Zeeman-effect techniques, we decomposed the numerical data into vectorial spherical harmonics. Results. A comparison of the trends we find in our simulations set reveals a promising overall agreement with the observational context of stellar magnetism, enabling us to suggest a plausible scenario for the magneto-rotational evolution of solar-type stars. In particular, we find that the magnetic field may reach a minimum amplitude at a transition value of the Rossby number near unity. This may have important consequences on the long-term evolution of solar-type stars, by impacting the relation between stellar age, rotation and magnetism. This supports the need for future observational campaigns, especially for stars in the high Rossby number regime.
format Preprint
id arxiv_https___arxiv_org_abs_2401_14460
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Magnetochronology of solar-type star dynamos
Noraz, Quentin
Brun, Allan Sacha
Strugarek, Antoine
Solar and Stellar Astrophysics
Aims. In this study, we analyse the magnetic field properties of a set of 15 global magnetohydrodynamics (MHD) simulations of solar-type star dynamos conducted using the ASH code. Our objective is to enhance our understanding of these properties by comparing theoretical results to current observations, and to finally provide fresh insights into the field. Methods. We analysed the rotational and magnetic properties as a function of various stellar parameters (mass, age and rotation rate) in a 'Sun in time' approach in our extended set of 3D MHD simulations. To facilitate direct comparisons with stellar magnetism observations using various Zeeman-effect techniques, we decomposed the numerical data into vectorial spherical harmonics. Results. A comparison of the trends we find in our simulations set reveals a promising overall agreement with the observational context of stellar magnetism, enabling us to suggest a plausible scenario for the magneto-rotational evolution of solar-type stars. In particular, we find that the magnetic field may reach a minimum amplitude at a transition value of the Rossby number near unity. This may have important consequences on the long-term evolution of solar-type stars, by impacting the relation between stellar age, rotation and magnetism. This supports the need for future observational campaigns, especially for stars in the high Rossby number regime.
title Magnetochronology of solar-type star dynamos
topic Solar and Stellar Astrophysics
url https://arxiv.org/abs/2401.14460