White Stars and Binary Stars

They seem to be only pinpoints of light in the night sky, but stars play an integral part in the universe. Learning about them has been an important part of science and special occurrences or transformations that stars may experience have always sparked our curiousity. White dwarfs and Binary stars are two special cases which will be covered here and more will be added later.

White Dwarfs--

White dwarfs are much smaller than main-sequence stars (ordinary stars like the sun) and lack the luminosity of a main-sequence star. They no longer have a supply of energy from fusion and while they may shine with a hot, while light, they will eventually fade away into cool dark embers.

It is believed that the gravity within white dwarfs is what shrinks them to their small size. This gravity produces high gas pressure as well as high density. The stars become so dense that a tablespoon of their gases would weigh tons if measured on the planet earth. Two white dwarfs include van Maanen's Star and Sirius B.

Binary Stars--

There are two kinds of binary or twin stars. One is visual binaries which can be seen through a telescope as two stars revolving around each other. It may take 100 years for one star to travel around the other. Then there are spectroscopic binaries which look like single stars, even when viewed through a telescope. It takes a spectroscope to identify them. These kind of stars complete their revolutions around each other in a few days to a few months. Two binaries include Mizar and Alcor which are two stars in the big dipper.