An Eclipsing Binary System Consists of

Multiple Choice

An eclipsing binary system consists of

A) a star that is periodically eclipsed by the Moon.
B) two stars that periodically eclipse each other, as seen from Earth.
C) two stars in which spectral lines move back and forth periodically due to Doppler shift, indicating mutually orbiting stars.
D) two mutually orbiting and gravitationally bound stars that are close enough to be resolved when viewed from Earth.