Page 16, The Stars I: [Previous Page] [Next Page] [Lecture Notes] [Class Home Page]

The Doppler effect can be used to study the motion of stars. BUT ONLY ALONG THE LINE OF SIGHT. The Study of Stellar Motions is particularly useful in studying binary stars.

Types of Binary Stars :

• Apparent -

  
  

True binary stars are gravitationally bound. They do not orbit each other, but their CENTER OF MASS and always opposite each other from that point in space. For any binary pair:


The low mass star (shown as M₁) will have to travel a very large diameter path, a₁, moving quickly. The high mass star (shown as M₂) travels a very small diameter path, a₂, and does so slowly.


• Visual -

  
  

• Spectroscopic -

  
  

• Eclipsing -