Question

Assume that an eclipsing binary contains two identical stars, but visually to us looks like a single star. (a) Sketch the apparent brightness of light received as a function of time. (b) Sketch to the same scale another light curve to show the result if both stars were much larger (though still appearing to us as a single star) while the orbit stayed the same.

Answer 1

In an eclipsing binary, if the light of the smaller star is only partially blocked by the larger one, the light curve would show a smaller dip in brightness when the smaller star passes in front of the larger star. The size of the stars can be estimated from the time intervals between contacts in the light curve.

Step-by-step explanation:

In an eclipsing binary with two identical stars, the light of one star is completely blocked by the other, resulting in a light curve that shows a strong dip in brightness when the blocked star passes behind the other star. However, if the light of the smaller star is only partially blocked by the larger one, the light curve would show a smaller dip in brightness when the smaller star passes in front of the larger star.

This can be seen by comparing the light curves of a hypothetical eclipsing binary with total eclipses and the light curves of a system where the smaller star is partially blocked. In the latter case, the relative positions of the two stars would correspond to various portions of the light curve, with a smaller dip in brightness when the smaller star is in front of the larger star.

The size of the stars in an eclipsing binary can be estimated from the time intervals between contacts in the light curve. Careful measurements of the light curve can help determine the diameters of the stars.