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Two-dimensional modeling of density and thermal structure of dense circumstellar outflowing disks

Identifikátory výsledku

  • Kód výsledku v IS VaVaI

    <a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F18%3A00113946" target="_blank" >RIV/00216224:14310/18:00113946 - isvavai.cz</a>

  • Nalezeny alternativní kódy

    RIV/00216224:14310/17:00095249

  • Výsledek na webu

    <a href="http://adsabs.harvard.edu/abs/2017arXiv171202908K" target="_blank" >http://adsabs.harvard.edu/abs/2017arXiv171202908K</a>

  • DOI - Digital Object Identifier

    <a href="http://dx.doi.org/10.1051/0004-6361/201731300" target="_blank" >10.1051/0004-6361/201731300</a>

Alternativní jazyky

  • Jazyk výsledku

    angličtina

  • Název v původním jazyce

    Two-dimensional modeling of density and thermal structure of dense circumstellar outflowing disks

  • Popis výsledku v původním jazyce

    Context. Evolution of massive stars is affected by a significant loss of mass either via (nearly) spherically symmetric stellar winds or by aspherical mass-loss mechanisms, namely the outflowing equatorial disks. However, the scenario that leads to the formation of a disk or rings of gas and dust around massive stars is still under debate. Aims. We study the hydrodynamic and thermal structure of optically thick, dense parts of outflowing circumstellar disks that may be formed around various types of critically rotating massive stars, for example, Be stars, B[e] supergiant (sgB[e]) stars or Pop III stars. Methods. We specify the optical depth of the disk along the line-of-sight from stellar poles. Within the optically thick dense region we calculate the vertical disk thermal structure using the diffusion approximation while for the optically thin outer layers we assume a local thermodynamic equilibrium with the impinging stellar irradiation. We use two of our own types of hydrodynamic codes: two-dimensional operator-split numerical code and unsplit code based on the Roe's method. Results. Our models show the geometric distribution and contribution of viscous heating that begins to dominate in the central part of the disk. In the models of dense viscous disks the viscosity increases the central temperature up to several tens of thousands of Kelvins. The high mass-loss rates and high viscosity lead to instabilities with significant waves or bumps in density and temperature in the very inner disk region. Conclusions. The two-dimensional radial-vertical models of dense outflowing disks including the full Navier-Stokes viscosity terms show very high temperatures that are however limited to only the central disk cores inside the optically thick area, while near the edge of the optically thick region the temperature may be low enough for the existence of neutral hydrogen.

  • Název v anglickém jazyce

    Two-dimensional modeling of density and thermal structure of dense circumstellar outflowing disks

  • Popis výsledku anglicky

    Context. Evolution of massive stars is affected by a significant loss of mass either via (nearly) spherically symmetric stellar winds or by aspherical mass-loss mechanisms, namely the outflowing equatorial disks. However, the scenario that leads to the formation of a disk or rings of gas and dust around massive stars is still under debate. Aims. We study the hydrodynamic and thermal structure of optically thick, dense parts of outflowing circumstellar disks that may be formed around various types of critically rotating massive stars, for example, Be stars, B[e] supergiant (sgB[e]) stars or Pop III stars. Methods. We specify the optical depth of the disk along the line-of-sight from stellar poles. Within the optically thick dense region we calculate the vertical disk thermal structure using the diffusion approximation while for the optically thin outer layers we assume a local thermodynamic equilibrium with the impinging stellar irradiation. We use two of our own types of hydrodynamic codes: two-dimensional operator-split numerical code and unsplit code based on the Roe's method. Results. Our models show the geometric distribution and contribution of viscous heating that begins to dominate in the central part of the disk. In the models of dense viscous disks the viscosity increases the central temperature up to several tens of thousands of Kelvins. The high mass-loss rates and high viscosity lead to instabilities with significant waves or bumps in density and temperature in the very inner disk region. Conclusions. The two-dimensional radial-vertical models of dense outflowing disks including the full Navier-Stokes viscosity terms show very high temperatures that are however limited to only the central disk cores inside the optically thick area, while near the edge of the optically thick region the temperature may be low enough for the existence of neutral hydrogen.

Klasifikace

  • Druh

    J<sub>imp</sub> - Článek v periodiku v databázi Web of Science

  • CEP obor

  • OECD FORD obor

    10308 - Astronomy (including astrophysics,space science)

Návaznosti výsledku

  • Projekt

    Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

  • Návaznosti

    P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>S - Specificky vyzkum na vysokych skolach

Ostatní

  • Rok uplatnění

    2018

  • Kód důvěrnosti údajů

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

Údaje specifické pro druh výsledku

  • Název periodika

    Astronomy and Astrophysics

  • ISSN

    0004-6361

  • e-ISSN

    1432-0746

  • Svazek periodika

    613

  • Číslo periodika v rámci svazku

    May 2018

  • Stát vydavatele periodika

    FR - Francouzská republika

  • Počet stran výsledku

    24

  • Strana od-do

    1-24

  • Kód UT WoS článku

    000434420000001

  • EID výsledku v databázi Scopus

    2-s2.0-85048882729