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Autori principali: Tschernitz, Johannes, Bourdin, Philippe-A.
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2502.02350
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author Tschernitz, Johannes
Bourdin, Philippe-A.
author_facet Tschernitz, Johannes
Bourdin, Philippe-A.
contents Surface convection is important for the presence of magnetic activity at stars. So far, this convection is thought to be a result of heating from below, where convection cells rise and break up. New models reveal that surface convection is instead strongly driven by cooling from above. We compare two simulations of surface convection, one with a significant heating from below and one without. We obtain surface convection in both cases, and they show similar granulation patterns. The deep convection driven by heating from below is still evolving and asymptotically approaches a steady-state solution. We find that convection from below is not needed at all to form typical photospheric granulation. This indicates the possibility of a surface dynamo acting on stars without a convecting envelope. Even stars without a convecting envelope could therefore exhibit stronger magnetic and coronal activity than expected so far.
format Preprint
id arxiv_https___arxiv_org_abs_2502_02350
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Granulation and Convectional Driving on Stellar Surfaces
Tschernitz, Johannes
Bourdin, Philippe-A.
Solar and Stellar Astrophysics
Plasma Physics
Surface convection is important for the presence of magnetic activity at stars. So far, this convection is thought to be a result of heating from below, where convection cells rise and break up. New models reveal that surface convection is instead strongly driven by cooling from above. We compare two simulations of surface convection, one with a significant heating from below and one without. We obtain surface convection in both cases, and they show similar granulation patterns. The deep convection driven by heating from below is still evolving and asymptotically approaches a steady-state solution. We find that convection from below is not needed at all to form typical photospheric granulation. This indicates the possibility of a surface dynamo acting on stars without a convecting envelope. Even stars without a convecting envelope could therefore exhibit stronger magnetic and coronal activity than expected so far.
title Granulation and Convectional Driving on Stellar Surfaces
topic Solar and Stellar Astrophysics
Plasma Physics
url https://arxiv.org/abs/2502.02350