Friday, June 06, 2008

Oh where oh where did my white dwarf go?

The more I study astronomy (playing fast and loose with that term, study, better to say avid reader I suspect) the more I am aware that there are stranger things in the universe than conceived in my own solar system. (oh yeah, goin to literary hell for that. yep yep). So what even participated this astronomical epiphany? An article in Science Daily concerning a white dwarf that should be present in the core of a planetary nebula and isn't to be found. What can be observed at the core is a pair of tightly bound stars that whirl around each other every five days, neither one of which is a white dwarf. (wait for it) Both stars also appear to be rotating more slowly than expected; they would be expected to always be facing the same sides toward each other, but they do not. The remaing two stars were born as a family of three, with the A stars circling each other tightly and a more massive star orbiting further out. This allowed room for the massive star to evolve to become a red giant, which only then engulfed the pair of A stars. Trapped inside the red giant in what astronomers call a "common envelope,"

Can you imagine that? Three stars close enough to orbit each other, so close in fact that when the most massive one goes off main sequence, the remaining stars are inside its' atmosphere!

The Science Daily article goes on to explain how this dynamic may have ejected the more massive star when it collapsed into a white dwarf, that in itself is every bit as interesting. Click here for complete article

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