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, stars and/or double:
“No one can doubt, that the convention for the distinction of property, and for the stability of possession, is of all circumstances the most necessary to the establishment of human society, and that after the agreement for the fixing and observing of this rule, there remains little or nothing to be done towards settling a perfect harmony and concord.”
—David Hume (1711–1776)
“America is the civilization of people engaged in transforming themselves. In the past, the stars of the performance were the pioneer and the immigrant. Today, it is youth and the Black.”
—Harold Rosenberg (1906–1978)
“Was it the double of my dream
The woman that by me lay
Dreamed, or did we halve a dream
Under the first cold gleam of day?”
—William Butler Yeats (1865–1939)