A white dwarf is a type of star that contains about as much matter as the Sun (nearly a million times as much as the Earth), but packed into a size no bigger than the Earth. Most of the stars in our galaxy will eventually become white dwarfs later in their lives - after the hydrogen fuel burning deep inside runs out. This won't happen to the Sun for another 5 billion years or so.

Some stars have already become white dwarfs, and astronomers can see them as tiny points of light in the sky, visible only through large telescopes. As it turns out, some of the white dwarfs show very regular variations in the amount of light reaching our telescopes. The pattern of this variation suggests that these white dwarfs are pulsating - as if there are continuous star-quakes going on. By studying the patterns of light variation, astronomers can learn about the interior structure of white dwarfs - in much the same way as seismologists can learn about the inside of the Earth by studying earthquakes. For this reason, the study of these pulsating white dwarfs is called asteroseismology.

The observations of pulsating white dwarfs are being done with the Whole Earth Telescope - a collaboration of astronomers around the world. I am involved in helping to make these observations, but I also work on interpreting them using our mathematical models. I approach the models in two ways:

  • I assume the models are accurate representations of the real white dwarf stars, and I try to find the combination of model parameters that do the best job of matching the observations.

  • I assume the models are flawed representations of the real white dwarf stars, and I try to find what changes to the physical laws governing the structure of the stars are possible without ruining the ability of the model to match the observations.

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