dipper@utastro.UUCP (Debbie Byrd) (03/03/85)
Most stars in our galaxy are double. More on cosmic companions -- right after this. March 3: Cosmic Companions It's natural to think that stars move through space alone. When we look up at night, the stars appear to be sprinkled one by one across the sky. But studies have shown that truly single stars are probably rather rare. In fact, most stars may belong to double or multiple systems. Without telescopes and special instruments we don't see that these systems contain more than one star. In many cases, one star is very bright while its companions are small and faint. Other times we don't see the companions because the whole system is so closely bound that it looks like a single star -- even through the greatest telescopes on Earth. And speaking of companions -- we haven't yet got definite proof of non-stellar companions for stars -- real planets. In the past year astronomers have discovered disks composed of small solid particles which are orbiting around some stars -- much the same way that Saturn's rings orbit that planet. And very recently a brown dwarf companion star was seen that one or two astronomers have chosen to call a planet -- even though it's actually a brightly shining red-hot ball of gas more than ten thousand times as massive as the earth! Regular planets -- like those in our solar system -- are very faint. If we traveled to the next-nearest star and turned our telescopes back toward the sun -- we wouldn't see planets here, either. But at least some stars probably do have real planets -- large relatively cold bodies shining in visible light reflected from their primary star. We may at last be on the verge of discovering them. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin