| KRTIČKA, Jiří, Jiří KUBÁT and Detlef GROOTE. Multicomponent radiatively driven stellar winds IV. On the helium decoupling in the wind of sigma Ori E. Astronomy and Astrophysics. Les Ulis Cedex, France: EDP Sciences, 2006, vol. 460, No 1, p. 145-153. ISSN 0004-6361. |
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@article{702572,
author = {Krtička, Jiří and Kubát, Jiří and Groote, Detlef},
article_location = {Les Ulis Cedex, France},
article_number = {1},
keywords = {stars: winds outflows - stars: mass-loss - stars: early-type - hydrodynamics - stars: chemically peculiar},
language = {eng},
issn = {0004-6361},
journal = {Astronomy and Astrophysics},
title = {Multicomponent radiatively driven stellar winds IV. On the helium decoupling in the wind of sigma Ori E},
url = {http://www.aanda.org/index.php?option=com_base_ora&access=standard&Itemid=129&url=articles/aa/abs/2006/46/aa5128-06/aa5128-06.html},
volume = {460},
year = {2006}
}
TY - JOUR
ID - 702572
AU - Krtička, Jiří - Kubát, Jiří - Groote, Detlef
PY - 2006
TI - Multicomponent radiatively driven stellar winds IV. On the helium decoupling in the wind of sigma Ori E
JF - Astronomy and Astrophysics
VL - 460
IS - 1
SP - 145-153
EP - 145-153
PB - EDP Sciences
SN - 00046361
KW - stars: winds outflows - stars: mass-loss - stars: early-type - hydrodynamics - stars: chemically peculiar
UR - http://www.aanda.org/index.php?option=com_base_ora&access=standard&Itemid=129&url=articles/aa/abs/2006/46/aa5128-06/aa5128-06.html
N2 - We study the possibility of the helium decoupling in the stellar wind of sigma Ori E. To obtain reliable wind parameters for this star we first calculate NLTE wind model and derive wind mass-loss rate and terminal velocity. Using corresponding force multipliers we study the possibility of helium decoupling. We find that helium decoupling is not possible for realistic values of helium charge (calculated from NLTE wind models). Helium decoupling only seems possible for a very low helium charge. The reason for this behavior is the strong coupling between helium and hydrogen. We also find that frictional heating becomes important in the outer parts of the wind of sigma Ori E due to the collisions between some heavier elements and the passive components - hydrogen and helium. For a metallicity ten times lower than the solar one, both hydrogen and helium decouple from the metals and may fall back onto the stellar surface. However, this does not explain the observed chemical peculiarity since both these components decouple together from the absorbing ions. Although we do not include the effects of the magnetic field into our models, we argue that the presence of a magnetic field will likely not significantly modify the derived results because in such case model equations describe the motion parallel to the magnetic field.
ER -
KRTIČKA, Jiří, Jiří KUBÁT and Detlef GROOTE. Multicomponent radiatively driven stellar winds IV. On the helium decoupling in the wind of sigma Ori E. \textit{Astronomy and Astrophysics}. Les Ulis Cedex, France: EDP Sciences, 2006, vol.~460, No~1, p.~145-153. ISSN~0004-6361.
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