D.) Distance travelled / time ...........
The answer would be A which is waves.
Answer and Explanation:
The binary system is a star system about half of the star are the part of the binary system
The important binary systems are
- Visual binary : in visual binary system the two stars resolved visually with nay sort of optical device the orbit of binary orbit is very large about center of mass.
- Spectroscopic binary : in this binary system the stars are detected by close analysis of light and after detection it is found that there are two seller spectrum present instead of one.
- Eclipsing binary : eclipsing binary system is a several types of variable stars this binary system is very important in astrophysics
