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 -