|
|
Other white dwarfs have been found pulsating, but they are doing it with hydrogen and helium -- not carbon, explained Williams. His colleague Michael Montgomery had, in fact, predicted this sort of carbon pulsation. That's what sent them, along with graduate student Steven DeGennaro, to McDonald Observatory's 2.1-meter Otto Struve Telescope to look at the dozen of known carbon white dwarfs which had been previously discovered by the Sloan Digital Sky Survey. The team's discovery appears in the May 1 issue of Astrophysical Journal Letters. "Of 20,000 known (white dwarfs) there were only 10 candidates," said Williams describing their hunt for hot carbon white dwarfs. Of those, only the one in Ursa Major proved to be pulsating. But that's enough for now, he said. "We know that Mike Montgomery's model works," Williams said. "That makes us very happy." As for how this and other carbon white dwarfs became so stripped down, that is a bit of a mystery, Williams said. One possibility it that the star was very close to the mass at which stars blow up as supernova at the end of their lives instead of becoming white dwarfs. So its corpse is, likewise, a borderline, strange dwarf. Luckily, the pulsations themselves may contain clues to the mystery in the form of seismic information from the interior of the white dwarf, said astronomer Michael Briley of the National Science Foundation. "This will allow us to probe the white dwarf's interior," said Briley, "which in turn should help us solve the riddle of where the carbon white dwarfs come from and what happens to their hydrogen and helium." Related Links: |
advertisement
Download Space News At Bottom!
|
