dipper@utastro.UUCP (Debbie Byrd) (01/31/86)
The first white dwarf was seen on this date in the year 1862. More about Sirius B -- when we come back. January 31 The First White Dwarf Most stars are suns, much like our own. But some stars are nothing like the sun. Modern astronomers have discovered many exotic stars -- black holes, pulsars, neutron stars and so on. But the first oddball star was discovered more than a century ago. Its name is Sirius B, and it's a white dwarf. On today's date in 1862, a famous telescope-maker, Alvan Clark, was testing a new telescope. He focused it on the place in the sky where the star Sirius was due to emerge from behind a building. And then he waited, staring through the eyepiece. Suddenly, just before Sirius appered, a tiny stellar pinpoint entered the field of view. It was a companion star to Sirius, later called Sirius B. Sirius B is 10 thousand times fainter than Sirius. Since Sirius is known to be an average- sized star, scientists knew that the companion must be incredibly small. Sirius B was later discovered to be only three times larger than the Earth. Because of this, and its white-hot color, it was called a "white dwarf." It's only three times larger than our planet -- but this star on an earthly scale would weigh some 250 thousand times more than Earth! Many white dwarf stars are known today. We know them to be very old stars whose internal fires have ceased. Without enough internal pressure for support, these stars collapse until they can shrink no further, creating a whole new species of matter. If even a thimbleful of white dwarf matter could be brought to Earth, it would weigh more than a ton. Script by Deborah Byrd. (c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin