Distinction Between Binary Stars and Other Double Stars
Visual double stars may be distinguished from binary stars by observing their relative motion. If the motion is part of an orbit, or if the stars have similar radial velocities or the difference in their proper motions is small compared to their common proper motion, the pair is probably physical. When observed over a short period of time, the components of both optical doubles and long-period visual binaries will appear to be moving in straight lines; for this reason, it can be difficult to distinguish between these two possibilities.
Read more about this topic: Double Star
Famous quotes containing the words distinction between, distinction, stars and/or double:
“If he does really think that there is no distinction between virtue and vice, why, Sir, when he leaves our houses let us count our spoons.”
—Samuel Johnson (1709–1784)
“A distinction of property results from that very protection which a free Government gives to unequal faculties of acquiring it.”
—James Madison (1751–1836)
“The sorrow of not being movie stars overwhelms millions.”
—Mason Cooley (b. 1927)
“I grew up confidently expecting to have a profession and earn my own living, and also confidently expecting to be married and have children. It was fifty-fifty with me. I was just as passionately determined to have children as I was to have a career. And my mother was the triumphant answer to all doubts as to the success of this double role. From my earliest memory she had more than half supported the family and yet she was supremely a mother.”
—Crystal Eastman (1881–1928)