Time-dependent modeling of extended thin decretion disks of
critically rotating stars

J 2014

Time-dependent modeling of extended thin decretion disks of critically rotating stars

KURFÜRST, Petr; Achim FELDMEIER a Jiří KRTIČKA

Základní údaje

Originální název

Time-dependent modeling of extended thin decretion disks of critically rotating stars

Autoři

KURFÜRST, Petr; Achim FELDMEIER a Jiří KRTIČKA

Vydání

Astronomy & Astrophysics, 2014, 0004-6361

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10308 Astronomy

Stát vydavatele

Francie

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 4.378

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/14:00073847

Organizační jednotka

Přírodovědecká fakulta

Klíčová slova anglicky

stars: mass-loss / stars: evolution / stars: rotation / hydrodynamics

Štítky

AKR, rivok

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 11. 4. 2015 22:26, Ing. Andrea Mikešková

Anotace

V originále

Context. During their evolution massive stars can reach the phase of critical rotation when a further increase in rotational speed is no longer possible. Direct centrifugal ejection from a critically or near-critically rotating surface forms a gaseous equatorial decretion disk. Anomalous viscosity provides the efficient mechanism for transporting the angular momentum outwards. The outer part of the disk can extend up to a very large distance from the parent star. Aims. We study the evolution of density, radial and azimuthal velocity, and angular momentum loss rate of equatorial decretion disks out to very distant regions. We investigate how the physical characteristics of the disk depend on the distribution of temperature and viscosity. Methods. We calculated stationary models using the Newton-Raphson method. For time-dependent hydrodynamic modeling we developed the numerical code based on an explicit finite difference scheme on an Eulerian grid including full Navier-Stokes shear viscosity. Results. The sonic point distance and the maximum angular momentum loss rate strongly depend on the temperature profile and are almost independent of viscosity. The rotational velocity at large radii rapidly drops accordingly to temperature and viscosity distribution. The total amount of disk mass and the disk angular momentum increase with decreasing temperature and viscosity. Conclusions. The time-dependent one-dimensional models basically confirm the results obtained in the stationary models as well as the assumptions of the analytical approximations. Including full Navier-Stokes viscosity we systematically avoid the rotational velocity sign change at large radii. The unphysical drop of the rotational velocity and angular momentum loss at large radii (present in some models) can be avoided in the models with decreasing temperature and viscosity.

Návaznosti

GA13-10589S, projekt VaV

Název: Ztráta hmoty horkých hmotných hvězd

Investor: Grantová agentura ČR, Ztráta hmoty horkých hmotných hvězd

Citovat

KURFÜRST, Petr; Achim FELDMEIER a Jiří KRTIČKA. Time-dependent modeling of extended thin decretion disks of critically rotating stars. Astronomy & Astrophysics. 2014, roč. 569, September, s. "nestránkováno", 7 s. ISSN 0004-6361. Dostupné z: https://doi.org/10.1051/0004-6361/201424272.

@article{1197256,
   author = {Kurfürst, Petr and Feldmeier, Achim and Krtička, Jiří},
   article_number = {September},
   doi = {https://doi.org/10.1051/0004-6361/201424272},
   keywords = {stars: mass-loss / stars: evolution / stars: rotation / hydrodynamics},
   language = {eng},
   issn = {0004-6361},
   journal = {Astronomy & Astrophysics},
   title = {Time-dependent modeling of extended thin decretion disks of critically rotating stars},
   url = {http://www.aanda.org/articles/aa/pdf/2014/09/aa24272-14.pdf},
   volume = {569},
   year = {2014}
}

TY  - JOUR
ID  - 1197256
AU  - Kurfürst, Petr - Feldmeier, Achim - Krtička, Jiří
PY  - 2014
TI  - Time-dependent modeling of extended thin decretion disks of critically rotating stars
JF  - Astronomy & Astrophysics
VL  - 569
IS  - September
SP  - "nestránkováno"
EP  - "nestránkováno"
SN  - 00046361
KW  - stars: mass-loss / stars: evolution / stars: rotation / hydrodynamics
UR  - http://www.aanda.org/articles/aa/pdf/2014/09/aa24272-14.pdf
N2  - Context. During their evolution massive stars can reach the phase of critical rotation when a further increase in rotational speed is no longer possible. Direct centrifugal ejection from a critically or near-critically rotating surface forms a gaseous equatorial decretion disk. Anomalous viscosity provides the efficient mechanism for transporting the angular momentum outwards. The outer part of the disk can extend up to a very large distance from the parent star. Aims. We study the evolution of density, radial and azimuthal velocity, and angular momentum loss rate of equatorial decretion disks out to very distant regions. We investigate how the physical characteristics of the disk depend on the distribution of temperature and viscosity. Methods. We calculated stationary models using the Newton-Raphson method. For time-dependent hydrodynamic modeling we developed the numerical code based on an explicit finite difference scheme on an Eulerian grid including full Navier-Stokes shear viscosity. Results. The sonic point distance and the maximum angular momentum loss rate strongly depend on the temperature profile and are almost independent of viscosity. The rotational velocity at large radii rapidly drops accordingly to temperature and viscosity distribution. The total amount of disk mass and the disk angular momentum increase with decreasing temperature and viscosity. Conclusions. The time-dependent one-dimensional models basically confirm the results obtained in the stationary models as well as the assumptions of the analytical approximations. Including full Navier-Stokes viscosity we systematically avoid the rotational velocity sign change at large radii. The unphysical drop of the rotational velocity and angular momentum loss at large radii (present in some models) can be avoided in the models with decreasing temperature and viscosity.
ER  -

KURFÜRST, Petr; Achim FELDMEIER a Jiří KRTIČKA. Time-dependent modeling of extended thin decretion disks of critically rotating stars. \textit{Astronomy \&{} Astrophysics}. 2014, roč.~569, September, s.~''nestránkováno'', 7 s. ISSN~0004-6361. Dostupné z: https://doi.org/10.1051/0004-6361/201424272.

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