Astronomy

Astronomy? Find a galaxy of information here.

Upgrade to Britannica Online

Take a tour, New improved britannica online

Imagine Britannica's 32-volume encyclopedia online right there for you, plus full access to articles. Amazing content, written by world experts, that you can cite for projects and assignments.

Click here for Britannica shop

eclipsing variable star

or eclipsing binary

Binary star in an orbit whose plane passes through or very near Earth. An observer on Earth sees one star pass periodically in front of the other and diminish its light through an eclipse. The star Algol, in the constellation Perseus, was the first such star recognized (1782); thousands are now known. By combining the brightness variations with spectroscopic information for both stars, astronomers can determine the mass and size of each star. See also variable star.

Find more information on eclipsing variable star. Upgrade to Britannica Online for more on eclipsing variable star.

  • Britannica, just as colourful as Singapore
  • Singapore is a legendary city. Britannica has a legendary reputation for knowledge. With just a few clicks you can access all the quality information you can trust, online.