The image shows the changes in light output over time of pulsating carbon white dwarf star.
Click on image for full size
Courtesy of K. Williams/ T. Jones/ McDonald Obs

Astronomers Discover New Type of Pulsating White Dwarf Star
News story originally written on May 1, 2008

Most of the stars in the universe, including the Sun, will end their lives as white dwarf stars. Astronomers have discovered a new type of white dwarf star, which is called a "pulsating carbon white dwarf."

A white dwarf star is what is leftover of a Sun-like star that has burned all of the fuel in its core. Recently, astronomers discovered a third type of white dwarf star. These "hot carbon white dwarfs" don't have their hydrogen and helium shells anymore, so their carbon layer is exposed. Since this discovery, astronomers have been searching to see if this new type of white dwarf star pulsates. They are interested in pulsating stars because the changes in the light a star puts out can show what goes on in its interior. This is similar to the way geologists study seismic waves from earthquakes to understand what goes on in Earth's interior. In fact, this type of star-study is called "asteroseismology."

So, astronomers names Michael H. Montgomery and Kurtis A. Williams began to study carbon white dwarfs with a telescope, looking for ones that pulsate. One of their graduate students, Steve DeGennaro, discovered a star about 800 light-years away in the constellation Ursa Major that fits the bill.

Studying these stars will shed light on how the surface of white dwarf stars lose their hydrogen and helium layers.

Last modified July 7, 2008 by Becca Hatheway.

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