14th European Workshop on White Dwarfs

Abstract. More than 40 years have passed since Ed Salpeter and others predicted that the carbon/oxygen cores of the coolest white dwarf stars in our Galaxy will theoretically crystallize. This effect has a dramatic impact on the calculated ages of cool white dwarfs, but until recently we have had no way of testing the theory. In 1992, pulsations were discovered in the massive potentially crystallized white dwarf BPM 37093, and in 1999 the theoretical effects of crystallization on the pulsation modes were determined. Observations from two Whole Earth Telescope campaigns in 1998 and 1999, combined with a new model-fitting method using a genetic algorithm, are now giving us the first glimpse inside of a crystallized star. 1. Crisis in the Cosmos In 1994, Ed Nather was reading the newspaper and came across a headline which read, “Crisis in the Cosmos- stars older than the universe”. Reading through the accompanying article, he learned that a group of astronomers had fit cosmological models to new observations from the refurbished Hubble Space