Figure 10-13 Representative Light Curves of Eclipsing Binaries The shape of the light curve (blue) reveals that the pairs of stars have orbits in planes nearly edge-on to our line of sight. It also provides details about the two stars that make up an eclipsing binary. Illustrated here are (a) a partial eclipse and (b) a total eclipse. (c) The binary star NN Serpens, indicated by the arrow, undergoes a total eclipse. The telescope was moved during the exposure so that the sky drifted slowly from left to right. During the 10.5-minute eclipse, the dimmer but larger star in the binary system (an M6 V star) passed in front of the more luminous but smaller star (a white dwarf). The binary became so dim that it almost disappeared.