The star Algol in the constellation Perseus has the following unusual characteristics.Every 68.75 hours its brightness dims suddenly from apparent magnitude 2.3 to apparent magnitude 3.5 and remains there for a few hours before returning just as suddenly to 2.3.In addition,halfway through this 68.75 hour period,the apparent magnitude becomes slightly dimmer than 2.3 for a few hours and then returns to 2.3.From this information alone it is possible to classify Algol as a(n):
A) optical double.
B) eclipsing binary.
C) totally eclipsing binary.
D) partially eclipsing binary.

Question

Quizplus · Accepted Answer

Algol's brightness dims at regular intervals and returns to its original brightness. This behaviour is characteristic of eclipsing binaries, where one star passes in front of the other from our point of view, causing the brightness to decrease. Algol is a particularly famous example of an eclipsing binary. The fact that the brightness decreases halfway through its period indicates that Algol is a partially eclipsing binary, with one star passing partially in front of the other.

The Star Algol in the Constellation Perseus Has the Following