Beta Lyrae is one of the easiest variable stars to find and observe, and also one of the most fascinating from a scientific point of view.
Algol's eclipses are dramatic but brief; the star fades to just one-third of its normal brightness in five hours, and recovers equally quickly. That makes it easy to tell when one of Algol's eclipses is happening, but it also means that there are relatively few good opportunities to view one.
here for a larger chart of Beta Lyrae's light curve.
You can estimate Beta's brightness by comparing it with the other five stars that make up Lyra's distinctive geometric shape. At its brightest, Beta is a near-twin of nearby Gamma Lyrae. But at the deepest part of its primary eclipse, Beta is the faintest (by a small margin) of Lyra's signature stars.
Beta Lyrae's gentle variation results from the fact that its components are so close to each other that they distort each other's shape and exchange material between them. To find out more about the fascinating physics behind this star, read this article by the American Association of Variable Star Observers (AAVSO).
J. M. Kreiner of the Mt. Suhora Astronomical Observatory in Poland maintains a Web page that predicts the eclipses for a huge number of eclipsing binaries. Click here to see his latest predictions for Beta Lyrae.
Beta Lyrae and Algol are two of the Top 12 Naked-Eye Variable Stars selected by notable variable-star observer John Isles in our May 1997 issue. Click here to retrieve the full article from our online PDF archive. All the light curves shown here are based on Isles's observations.