The gas drag effect in the primordial solar nebula on the motion of a solid body, ranging from a large planetesimal to a small dust grain, is investigated. For a planetesimal, expressions for the short-term variation of the semi-major axis, the eccentricity and inclination are obtained using a perturbation method and a realistic formula for the gas drag force.
For a small body, an orbit spiralling towards the sun in the equatorial plane of the nebula is investigated and the decay time of the orbital radius is obtained. It is found that the decay time at 1 a.u. is as short as 102 or 103 years for a solid body with mass in the range between 103 g and 108 g.
Statistical Behavior of Planetesimals in the Primitive Solar System Yoshitsugu Nakagawa
Gravitational Instabilities in a Dust-Gas Layer and Formation of Planetesimals in the Solar Nebula Minoru Sekiya
Drag on a Gravitating Sphere Moving through a Gas Hidenori Takeda, Takuya Matsuda, Keisuke Sawada and Chushiro Hayashi
Gas Drag on a Rotating Body with Gravity Hidenori Takeda and Yoshitsugu Nakagawa
Origin of the Solar System Kiyoshi Nakazawa and Yoshitsugu Nakagawa
Chapter 17. Drag on a Gravitating Body Hidenori Takeda
Chapter 20. Accumulation Process of Planetesimals to the Planets Keiji Ohtsuki and Yoshitsugu Nakagawa