dipper@utastro.UUCP (Debbie Byrd) (11/19/84)
Astronomers know at least one star that may spin on its axis some 640 times per second. More on millisecond pulsars -- right after this. November 19 Millisecond Pulsars Pulsars were discovered in 1967. A pulsar is like a lighthouse star that emits a discreet pulse of radio energy from a spot, or pair of spots, on its surface. So each time a pulsar spins, we on Earth see a pulse of radio energy. Most pulsars pulse once every fraction of a second -- or once every few seconds -- but two pulsars have been found that pulse hundreds of times in a single second. These objects -- which then would be spinning around hundreds of times each second -- are known as millisecond pulsars. The first millisecond pulsar was found only a few years ago, in 1982. The second one was found the following year. Like other pulsars, these objects are believed to be neutron stars -- incredibly dense stars formed in supernova explosions. As material blows outward from a supernova, the core of the star is crushed inward to an extreme density -- and a neutron star is made. The problem with millisecond pulsars -- which again pulse hundreds of times each second -- and therefore are thought to spin around hundreds of times in a single second -- is that they may be accountable only if they lie in double star systems. Material from a companion to the neutron stars may be causing these stars to speed up their spins -- but if that's the case, then how did the companion survive the indescribable violence of a supernova explosion -- which gave birth to the pulsar in the first place? The answers aren't all in -- but the millisecond pulsars are a new mystery for astronomers to think about. Script by Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin