Dynamics and stability of radiatively driven gas clouds. I. Plane-parallel slabs

Journal Article · Thu Nov 01 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157445· OSTI ID:5730668

Haas, M R

A combination of numerical and analytical techniques has been used to investigate the dynamics and stability of optically thin, plane-parallel, radiatively driven slabs of gas which are confined by the thermal gas pressure of a high-temperature, low-density medium. Scaling laws allow the individual model ''clouds'' to be characterized by a single free parameter chi, a normalized column density which measures the strength of the acceleration due to radiation pressure relative to that due to thermal gas pressure. It is found that these clouds are stable and coherently accelerated only when chi is small. In this regime a simple slab model is constructed which accurately reproduces the more complex gas-dynamic results. The low-chi clouds are marginally able to reach the high velocities seen in the atmospheres of quasi-stellar objects, but only if their motion is subsonic with respect to the external, confining medium. This implies either that the medium is extremely hot and tenuous or that it is moving outward with the clouds.

• Research Organization: Space Science Division, NASA Ames Research Center
• OSTI ID: 5730668
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 233:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCELERATION
ADIABATIC PROCESSES
COSMIC GASES
COSMIC RADIO SOURCES
FLUID MECHANICS
FLUIDS
GASES
HYDRODYNAMICS
MECHANICS
NEBULAE
QUASARS
RADIATION PRESSURE
RADIATION TRANSPORT
STABILITY