Binary Stars

A binary star system consists of two stars which orbit around a common point, called the center of mass following Kepler's Laws.

Five to ten percent of the stars visible to us are visual binary stars. Careful spectroscopic studies of nearby solar-type stars show that about two thirds of them have stellar companions. We estimate that roughly half of all stars in the sky are indeed members of binaries.

One of the fundamental properties that we want to know about a star is its mass. The only way that we can determine the masses of stars is to study the orbital motions of binary stars. Application of the laws of celestial mechanics allows us to calculate the masses of the stars from measures of their orbital periods, sizes and velocities.

Link here to the Astro 101 binary star simulations.


[back to the topics page] [back to astro 2201 home page] [back to Astro 2201 FAQ page] [back to Astro 233 FAQ page]