Artist's impression of AE Aqr
Credit:Terada et al.; JAXA; NASA; Artist: Casey Reed

The Beating of the Dwarf

White dwarfsare cinders left behind after low mass stars have run out of hydrogen fuel and their outer atmospheres have drifted away into space. These objects are very hot when first revealed but they rather quickly grow cool and faint beyond detectability. No one knows how many white dwarfs there are in our Galaxy. Sometimes white dwarfs are gravitationally bound to a "normal" companion star, and can draw matter off the companion and rejuvenate themselves somewhat by the power of this accretion. When this happens sometimes surprising things can occur. One such surprise was detected by the Suzaku X-ray observatory. Astronomers using Suzaku to monitor a white dwarf binary star system called AE Aqr (shown in the artist interpretation above) found something never before seen: regular beats or pulses of hard X-ray emission. These pulsations are believed to originate near the poles of this highly magnetized white dwarf. A similar mechanism operates in neutron stars, much rarer objects produced by the collapse of the core of a high mass star. This is the first time pulsations like this have been seen from a white dwarf. How many other pulsing dwarfs are out there?

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Page Author: Dr. Michael F. Corcoran
Last modified Friday, 20-Apr-2012 15:20:51 EDT