ASTR 1100 Lecture Notes - Lecture 13: Orbital Period, Lunar Eclipse, Binary Star
Document Summary
Two stars that affect each other via gravity. => two stars orbiting a gravitational point between them. First introduced by william herschel in 1802. They are used to determine mass of stars. They orbit their common center of mass, which lies closer to the more massive star. Not all stars that appear close to each other are binaries. Some are optical double stars, they only lie in the same direction as seen from earth, but in fact are very far away from each other. They do not orbit their common center of mass. Three types of binaries: visual binaries: => both stars can be seen through a telescope. => they can be observed and monitored separately: spectroscopic binaries: => too distant from us to be resolved in to separate stars. => they can be indirectly perceived by monitoring the back and forth doppler shifts of their spectral lines as the stars orbit one another: eclipsing binaries:
