We identify at least four different types of binary star systems, depending on how we observe them.  Each type has some unique observational characteristics.  Here is Phil Plait to give you an excellent introduction.  Pay attention, there’ll be an open note quiz immediately after the video! Each type of binary star system is by no means exclusive.  A pair of stars could possibly belong to more than one of these classifications. Visual Binaries Eclipsing Binaries Astrometric Binaries Spectroscopic Binaries As you may know, Tatooine is a planet that orbits a binary star.  Is that really possible?  Yes!  Watch this!
Looking for a particular star?  Find it here!
Binary Stars
Carpe Caelum
Carpe Caelum Stellar Astronomy