Granulation and Convectional Driving on Stellar Surfaces
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 tw...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/adac4f |
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| author | Johannes Tschernitz Philippe-A. Bourdin |
| author_facet | Johannes Tschernitz Philippe-A. Bourdin |
| author_sort | Johannes Tschernitz |
| collection | DOAJ |
| description | 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 | Article |
| id | doaj-art-1aeabeaa261740f78272faaf1d9da376 |
| institution | Kabale University |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-1aeabeaa261740f78272faaf1d9da3762025-02-03T17:26:59ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019792L3910.3847/2041-8213/adac4fGranulation and Convectional Driving on Stellar SurfacesJohannes Tschernitz0https://orcid.org/0000-0002-2004-222XPhilippe-A. Bourdin1https://orcid.org/0000-0002-6793-601XUniversity of Graz , Universitätsplaz 5, 8010 Graz, Austria ; johannes.tschernitz@tu-braunschweig.de; Now at: TU Braunschweig , Mendelssohnstraße 3, 38106 Braunschweig, GermanyUniversity of Graz , Universitätsplaz 5, 8010 Graz, Austria ; johannes.tschernitz@tu-braunschweig.de; Space Research Institute , Austrian Academy of Sciences, Schmiedlstr. 6, 8042 Graz, AustriaSurface 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.https://doi.org/10.3847/2041-8213/adac4fSolar granulationStellar granulationSolar radiationSolar convective zoneStellar convection envelopes |
| spellingShingle | Johannes Tschernitz Philippe-A. Bourdin Granulation and Convectional Driving on Stellar Surfaces The Astrophysical Journal Letters Solar granulation Stellar granulation Solar radiation Solar convective zone Stellar convection envelopes |
| title | Granulation and Convectional Driving on Stellar Surfaces |
| title_full | Granulation and Convectional Driving on Stellar Surfaces |
| title_fullStr | Granulation and Convectional Driving on Stellar Surfaces |
| title_full_unstemmed | Granulation and Convectional Driving on Stellar Surfaces |
| title_short | Granulation and Convectional Driving on Stellar Surfaces |
| title_sort | granulation and convectional driving on stellar surfaces |
| topic | Solar granulation Stellar granulation Solar radiation Solar convective zone Stellar convection envelopes |
| url | https://doi.org/10.3847/2041-8213/adac4f |
| work_keys_str_mv | AT johannestschernitz granulationandconvectionaldrivingonstellarsurfaces AT philippeabourdin granulationandconvectionaldrivingonstellarsurfaces |