A THEORY OF DUST COMETS,
Abstract
A model based on kinetic and fluid dynamic concepts is formulated for the head and tail regions of dust comets. In the model, dust particles having a wide distribution of sizes are released from the comet nucleus in an essentially continuous manner in time during the period of distinctive cometary phenomena due to solar heating. The dust particles are accelerated radially outward from the nucleus by drag forces due to the expanding comet head gas. After leaving this region, the only significant forces assumed to act on the dust particles are the solar gravity and the solar radiation pressure. Observed nonradial dust tail orientations are explainable by this model. Calculated surface density distributions are compared with measured light intensity distributions for Comet Arend-Roland, from which the distribution of dust particle sizes, the dust and head gas emission rates as functions of time, and the emission velocity from the inner head region as a function of particle size and time, are determined essentially for the first time. Dust particle diameters on the order of 1 micron and a size distribution similar to those obtained for interplanetary dust are found. For Comet Arend-Roland, near its perihelion, high dust and gas emission rates are found, confirming previous estimates. An outburst in the dust emission is deduced to have occurred in Comet Arend-Roland about six days before perihelion. It is suggested that dust-rich comets emit larger amounts of dust during their approach to the sun than during recession. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1967
- Accession Number
- AD0660652
Entities
People
- Michael L. Finson
- Ronald F. Probstein
Organizations
- Massachusetts Institute of Technology