Suppose that two stars in a binary star system are separated by a distance of 80 million kilometers and are located at a distance of 150 light-years from earth.
a) what is the angular separation of the two stars in degrees?
b) what is the angular separation in arceseconds?

1) Angular separation equals 0.0000031 degrees

2) Angular separation in arc -seconds equals 0.011156"

Explanation:

For 2 stars separated by a distance 'S' and at a distance 'D' from the earth the angular separation in radians is given

Applying values we get

Now we know that 'π' radians equals 180 degrees thus the above value in degrees shall be equal to

2)

The angular separation in arc- seconds is given by