Fig7_9 Double stars

Fig7_9 Double stars

Fig. 7.9 . Two close stars are joined in a gravitational embrace, orbiting each other and forming a binary star system (top and bottom). The orbital period and linear star separation can be used to determine the sum of their masses. If the orbital plane of the two companions is sufficiently inclined and within the line of sight, the star system becomes an eclipsing binary (top), in which one star is observed to pass behind the other one and vice versa; this can provide additional information about the stars.

Copyright 2010, Professor Kenneth R. Lang, Tufts University