A magnetic betelgeuse? Numerical simulations of non-linear dynamo action

219th IAU Symposium on Stars as Suns - Activity, Evolution, and Planets, JUL 21-25, 2003 Sydney, AUSTRALIA

Publikation: Bidrag til tidsskriftTidsskriftartikelForskning

Resumé

Udgivelsesdato: Jan 2004
OriginalsprogEngelsk
TidsskriftSymposium - International astronomical union
Vol/bind219
Sider (fra-til)656-660
ISSN0074-1809
StatusUdgivet - 2004
Udgivet eksterntJa

Fingeraftryk

planets
stars
convection cells
simulation
brightness
envelopes
kinematics
luminosity
magnetic fields

Citer dette

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title = "A magnetic betelgeuse? Numerical simulations of non-linear dynamo action: 219th IAU Symposium on Stars as Suns - Activity, Evolution, and Planets, JUL 21-25, 2003 Sydney, AUSTRALIA",
abstract = "Betelgeuse is an example of a cool super-giant displaying brightness fluctuations and irregular surface structures. Simulations by Freytag et al. (2002) of the convective envelope of the star have shown that the fluctuations in the star's luminosity may be caused by giant cell convection. A related question regarding the nature of Betelgeuse and supergiants in general is whether these stars may be magnetically active. If so, that may in turn also contribute to their variability. By performing detailed numerical simulations, I find that both linear kinematic and non-linear dynamo action are possible and that the non-linear magnetic field saturates at a value somewhat below equipartition: in the linear regime there are two modes of dynamo action.",
author = "Dorch, {S. B. F.}",
year = "2004",
language = "English",
volume = "219",
pages = "656--660",
journal = "Proceedings of the International Astronomical Union",
issn = "1743-9213",
publisher = "Heinemann",

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TY - JOUR

T1 - A magnetic betelgeuse? Numerical simulations of non-linear dynamo action

T2 - 219th IAU Symposium on Stars as Suns - Activity, Evolution, and Planets, JUL 21-25, 2003 Sydney, AUSTRALIA

AU - Dorch, S. B. F.

PY - 2004

Y1 - 2004

N2 - Betelgeuse is an example of a cool super-giant displaying brightness fluctuations and irregular surface structures. Simulations by Freytag et al. (2002) of the convective envelope of the star have shown that the fluctuations in the star's luminosity may be caused by giant cell convection. A related question regarding the nature of Betelgeuse and supergiants in general is whether these stars may be magnetically active. If so, that may in turn also contribute to their variability. By performing detailed numerical simulations, I find that both linear kinematic and non-linear dynamo action are possible and that the non-linear magnetic field saturates at a value somewhat below equipartition: in the linear regime there are two modes of dynamo action.

AB - Betelgeuse is an example of a cool super-giant displaying brightness fluctuations and irregular surface structures. Simulations by Freytag et al. (2002) of the convective envelope of the star have shown that the fluctuations in the star's luminosity may be caused by giant cell convection. A related question regarding the nature of Betelgeuse and supergiants in general is whether these stars may be magnetically active. If so, that may in turn also contribute to their variability. By performing detailed numerical simulations, I find that both linear kinematic and non-linear dynamo action are possible and that the non-linear magnetic field saturates at a value somewhat below equipartition: in the linear regime there are two modes of dynamo action.

M3 - Journal article

VL - 219

SP - 656

EP - 660

JO - Proceedings of the International Astronomical Union

JF - Proceedings of the International Astronomical Union

SN - 1743-9213

ER -