Eclipsing Binary Stars

This movie simulates an eclipsing binary star system consisting of an A0v primary and G5v secondary in a circular orbit about each other. The orbital plane is tilted with respect to the line of sight by 6°. The top half of the frame shows the appearance of the two stars, with the red dot marking the center of mass of the system (just outside the radius of the blueish A0v primary star). The light curve of the total system is traced out in the lower panel as they orbit. Two orbits full orbits are shown, with a red marker used on the light curve to show the current location.

Notice that the deepest eclipse occurs when the secondary is in front of the primary. This is because of the nearly factor of two greater effective temperature of the primary (10,000K compared to 5,500K). Since surface brightness scales like T⁴, more light is blocked when the secondary is blocking part of the primary, than when the primary completely blocks the secondary.

[Credit: R. Pogge, OSU]
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Updated: 2007 November 3 [rwp]