TY - JOUR

T1 - On the quasi-hydrostatic flows of radiatively cooling self-gravitating gas clouds

AU - Meerson, Baruch

AU - Megged, Ephraim

AU - Tajima, Toshiki

PY - 1996

Y1 - 1996

N2 - Two model problems are considered, illustrating the dynamics of quasi-hydrostatic flows of radiatively cooling, optically thin self-gravitating gas clouds. In the first problem, spherically symmetric flows in an unmagnetized plasma are considered. For a power-law dependence of the radiative loss function on the temperature, a one-parameter family of similarity solutions is found. We concentrate on a constant-mass cloud, one of the cases when the similarity indices are uniquely selected. In this case, the problem can be formally reduced to the classical Lane-Emden equation and therefore solved analytically. The cloud is shown to undergo radiative condensation, if the gas specific heat ratio γ is greater than 4/3. The condensation proceeds either gradually or in the form of (quasi-hydrostatic) collapse. For γ < 4/3, the cloud is shown to expand. The second problem addresses a magnetized plasma slab that undergoes quasi-hydrostatic radiative cooling and condensation. The problem is solved analytically, employing the Lagrangian mass coordinate.

AB - Two model problems are considered, illustrating the dynamics of quasi-hydrostatic flows of radiatively cooling, optically thin self-gravitating gas clouds. In the first problem, spherically symmetric flows in an unmagnetized plasma are considered. For a power-law dependence of the radiative loss function on the temperature, a one-parameter family of similarity solutions is found. We concentrate on a constant-mass cloud, one of the cases when the similarity indices are uniquely selected. In this case, the problem can be formally reduced to the classical Lane-Emden equation and therefore solved analytically. The cloud is shown to undergo radiative condensation, if the gas specific heat ratio γ is greater than 4/3. The condensation proceeds either gradually or in the form of (quasi-hydrostatic) collapse. For γ < 4/3, the cloud is shown to expand. The second problem addresses a magnetized plasma slab that undergoes quasi-hydrostatic radiative cooling and condensation. The problem is solved analytically, employing the Lagrangian mass coordinate.

KW - Hydrodynamics

KW - Instabilities

KW - MHD

KW - Stars: Formation

UR - http://www.scopus.com/inward/record.url?scp=21844504153&partnerID=8YFLogxK

U2 - 10.1086/176731

DO - 10.1086/176731

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AN - SCOPUS:21844504153

SN - 0004-637X

VL - 457

SP - 321

EP - 331

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 1 PART I

ER -