Structure and evolution of the solar nebula

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:5930249

Ruden, S P

Accretion disk models for the formation of the primordial solar nebula were developed to address the important issues of the origin and prescription for turbulence in the disk. The calculations follow the time-dependent changes in the vertical structure of the solar nebula as it grows by mass accretion. The effects of shock heating of the nebular surface and gravitational energy release due to the settling of newly accreted matter are included in the computations. As the surface density and vertical optical depth of the disk increase, the nebula becomes able to trap the heat generated internally by the settling of matter in the gravitational field of the protosun. The central temperature of the nebular annulus then increases with time, but the temperature gradient remains subadiabatic as long as the accretion rate remains constant, However, as accretion terminates and the surface cools, a superadiabatic vertical temperature gradient develops if the nebular opacity has a sufficiently large temperature dependence. Finally, the presence of a superadiabatic temperature gradient causes thermal convection to ensue. Convective eddies, in addition to their contribution to heat transport, are efficient at inducing radial angular momentum transfer and turbulent viscous energy dissipation.

• Research Organization: California Univ., Santa Cruz (USA)
• OSTI ID: 5930249
• Country of Publication: United States
• Language: English

Related Subjects

640104* -- Astrophysics & Cosmology-- Solar Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ACCRETION DISKS
CONVECTION
ENERGY TRANSFER
FUNCTIONAL MODELS
GRAVITATIONAL FIELDS
HEAT TRANSFER
HEATING
MASS TRANSFER
NEBULAE
PLASMA HEATING
SHOCK HEATING
SOLAR NEBULA
STAR ACCRETION
STAR EVOLUTION
TEMPERATURE GRADIENTS