Models of the formation of the solar nebula
Abstract
Models of the collapse of a protostellar cloud and the formation of the solar nebula reveal that the size of the nebula produced will be the larger of R _{CF} ≡ J ^{2}/k ^{2}GM ^{3}and R _{V} ≡ (GMv/2c _{c}^{3}) 1/2 (where J, M, and c_{s} are the total angular momentum, total mass, and sound speed of the protosetellar material; G is the gravitational constant; k is a number of order unity; and v is the effective viscosity in the nebula). From this result it can be deduced that lowmass nebulas are produced if P ≡ ( R_{V}/ R_{CF}) ^{2} ≫ 1; "massive" nebulas result if P ≲ 1. Gravitational instabilities are expected to be important for the evolution of P ≪ 1 nebulas. The value of J distinguishes most current models of the solar nebula, since P ∝ J^{4}. Analytic expressions for the surface density, nebular mass flux, and photospheric temperature distributions during the formation stage are presented for some simple models that illustrate the general properties of growing protostellar disks. It does not yet seem possible to rule out either P ≫ 1 or P < 1 for the solar nebula, but observed or possible heterogeneities in composition and angularmomentum orientation favor P < 1 models.
 Publication:

Icarus
 Pub Date:
 January 1983
 DOI:
 10.1016/00191035(83)900180
 Bibcode:
 1983Icar...53...26C
 Keywords:

 Gravitational Collapse;
 Interplanetary Medium;
 Protoplanets;
 Protostars;
 Solar Corona;
 Solar System;
 Angular Momentum;
 Astronomical Models;
 Cosmology;
 Evolution (Development);
 Photosphere;
 Solar Temperature;
 Solar Physics