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:
“The distinction between children and adults, while probably useful for some purposes, is at bottom a specious one, I feel. There are only individual egos, crazy for love.”
—Don Barthelme (1931–1989)
“Genocide begins, however improbably, in the conviction that classes of biological distinction indisputably sanction social and political discrimination.”
—Andrea Dworkin (b. 1946)
“Young men of the fairest promise, who begin life upon our shores, inflated by the mountain winds, shined upon by all the stars of God, find the earth below not in unison with these,—but are hindered from action by the disgust which the principles on which business is managed inspire, and turn drudges, or die of disgust,—some of them suicides.”
—Ralph Waldo Emerson (1803–1882)
“Even in harmonious families there is this double life: the group life, which is the one we can observe in our neighbour’s household, and, underneath, another—secret and passionate and intense—which is the real life that stamps the faces and gives character to the voices of our friends. Always in his mind each member of these social units is escaping, running away, trying to break the net which circumstances and his own affections have woven about him.”
—Willa Cather (1873–1947)