The Effect of Star Passages on Cometary Orbits in the Oort Cloud
Abstract
Close encounters between stars and comets in the Oort cloud without restrictions with respect to orbital elements are investigated systematically by numerical integrations. The dependency of changes in cometary orbits after close stellar encounters on the parameters of the problem, namely stellar mass, relative velocity, missdistance, and orbital configuration, is derived quantitatively. A comparison with the impulse formula for changes in cometary velocities after close stellar encounters gives the limits for the validity of this formula. For relative velocities between 5 and 10 km/sec., the impulse formula yields slightly larger perihelion distances than the complete model here. Another comparison shows that models which omit the passing star's gravitational pull on the sun yield also slightly larger distances but only for low velocity encounters (less than or equal to 10 km/sec.). This statement is only valid for close encounters at aphelion distances in the range 20,000 AU  150,000 AU.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 August 1982
 Bibcode:
 1982A&A...112..157S
 Keywords:

 Astronomical Models;
 Comets;
 Numerical Integration;
 Oort Cloud;
 Orbit Perturbation;
 Orbital Elements;
 Stellar Gravitation;
 Miss Distance;
 Numerical Analysis;
 Solar System;
 Stellar Mass;
 Stellar Motions;
 Astronomy