Horizontal flows in the atmospheres of chemically peculiar stars

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985815%3A_____%2F25%3A00617662" target="_blank" >RIV/67985815:_____/25:00617662 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216224:14310/25:00141405

Výsledek na webu

<a href="https://hdl.handle.net/11104/0365407" target="_blank" >https://hdl.handle.net/11104/0365407</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202453189" target="_blank" >10.1051/0004-6361/202453189</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Horizontal flows in the atmospheres of chemically peculiar stars

Popis výsledku v původním jazyce

Context. Classical chemically peculiar stars exhibit atmospheres that are often structured by the effects of atomic diffusion. As a result of these elemental diffusion and horizontal abundance variations, the photospheric temperature varies at a given height in the atmosphere. This may lead to horizontal flows in the photosphere. In addition, the suppression of such flows by a magnetic field can alter the elemental transport processes. Aims. Using a simplified model of such a structured atmosphere and 2D magnetohydrodynamic simulations of a typical He-rich star, we examined atmospheric flows in these chemically peculiar stars, which often are strongly magnetic. Methods. We used Zeus-MP, which is a publicly available Fortran 90-based parallel finite element modular code. Results. We find that for non-magnetic stars of spectral type BA, the atmospheric flow related to the horizontal temperature gradient can reach 1.0 km s(-1), yielding mixing timescales of the order of tens of days. For the magnetic counterparts, the flow speeds are an order of magnitude lower, allowing for the stratification of chemical elements. Conclusions. Magnetic fields can significantly influence the dynamics in atmospheres. A strong horizontal magnetic field inhibits flow in the vertical direction, while a strong vertical magnetic field can suppress horizontal atmospheric flow and prevent elemental mixing.

Název v anglickém jazyce

Horizontal flows in the atmospheres of chemically peculiar stars

Popis výsledku anglicky

Context. Classical chemically peculiar stars exhibit atmospheres that are often structured by the effects of atomic diffusion. As a result of these elemental diffusion and horizontal abundance variations, the photospheric temperature varies at a given height in the atmosphere. This may lead to horizontal flows in the photosphere. In addition, the suppression of such flows by a magnetic field can alter the elemental transport processes. Aims. Using a simplified model of such a structured atmosphere and 2D magnetohydrodynamic simulations of a typical He-rich star, we examined atmospheric flows in these chemically peculiar stars, which often are strongly magnetic. Methods. We used Zeus-MP, which is a publicly available Fortran 90-based parallel finite element modular code. Results. We find that for non-magnetic stars of spectral type BA, the atmospheric flow related to the horizontal temperature gradient can reach 1.0 km s(-1), yielding mixing timescales of the order of tens of days. For the magnetic counterparts, the flow speeds are an order of magnitude lower, allowing for the stratification of chemical elements. Conclusions. Magnetic fields can significantly influence the dynamics in atmospheres. A strong horizontal magnetic field inhibits flow in the vertical direction, while a strong vertical magnetic field can suppress horizontal atmospheric flow and prevent elemental mixing.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

<a href="/cs/project/GA22-34467S" target="_blank" >GA22-34467S: Interakce dvojhvězd na větvi červených obrů: horcí podtrpaslíci jako testovací případ.</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Svazek periodika

694

Číslo periodika v rámci svazku

Feb.

Stát vydavatele periodika

FR - Francouzská republika

Počet stran výsledku

5

Strana od-do

A270

Kód UT WoS článku

001425521700010

EID výsledku v databázi Scopus

2-s2.0-85218422087