Visual Binary Stars
These movies simulate the orbit of a visual binary star pair consisting of
an F0v primary and M0v secondary. The orbital plane of the two is in the
plane of the sky. The two stars have a mass ratio of about 3.6,
appropriate for stars of this type.
This movie shows the two stars in circular orbits about their center of
mass (marked with the green dot). Two orbits are shown, with the orbit
traced as a white line. Both stars move at a uniform speed around the
center of mass, the more massive, blueish F0v star moves less as it is
closer to the center-of-mass than the less massive, reddish M0v star.
Elliptical Orbit (e=0.4):
This movie shows the two stars in elliptical orbits about their center of
mass, with an orbital eccentricity of 0.4. Watch how both stars noticeably
speed up and slow down as they pass periastron (closest approach to the
C-of-M) and apastron (farthest from C-of-M), respectively, thus obeying
Kepler's Second Law (equal areas in equal times) the same as the planets in
the Solar System.
[Credit: R. Pogge, OSU]
Lecture 9 Page
Unit 1 Page
Astronomy 162 Homepage]
Prof. Richard Pogge (firstname.lastname@example.org)
Updated: 1998 January 10 [rwp]
Copyright © 1998
Richard W. Pogge, All Rights Reserved.