Black Holes and White Dwarves

This just in from the Chandra X-Ray observatory – it would appear that a black hole is eating a white dwarf! Technically, it was eating a black hole, about 65 million years ago…

There’s a few interesting anomalies about this event that are bound to refine astronomical information – Phil Plait, of course, has an excellent rundown in his informational and bombastic style, but if you’re willing to put up with me for a few paragraphs more…

First off; the star being pulled in is likely a White Dwarf (or a “degenerate dwarf” if you like the D&D style sound of that); these stars are hydrogen and helium poor, and rich in heavier metals that make the X-Ray emissions from this event distinctive.

Secondly, from the spectra of the infalling material, you can get an idea as to how fast the matter is falling in – giving you an idea of how large the black hole is. And this one is a strange size – not too big, not too small, a “middleweight” hole that had been suspected to exist, but never observed.

It will take the black hole about 100 years to eat this X-ray spewing dwarf, the core of which is made of a strange sort of matter – degenerate matter. This is a form of matter that can no longer be compressed, at this point quantum mechanics comes into play, and the matter is prevented from collapsing further because doing so would mean that elemental particles would have to occupy the same space.

That is a lot of pressure. And it is a real effect that exerts actual expansive force, holding up the core of the star against collapse. This pressure is called degeneracy pressure.

If one of the stars in a binary star system becomes a white dwarf, and the other star is close enough, the white dwarf will actually pull star matter from it’s partner onto the surface of the white dwarf. With the addition of this matter, the white dwarf will eventually become so massive that the pressure overcomes the degeneracy pressure.

Then the shit blows up and it’s called a Type Ia Supernova.

So what Chandra is observing is sort of the reverse phenomenon. I can’t imagine that things will blow up, but we’ve got another hundred years of watching to see what happens when that degenerate matter turns back to normal gas.

Now, I’m no astrophysicist (which is why I read Phil P’s blog in the first place) but it could be interesting to see – the degenerate matter will eventually become gaseous again as the white dwarf loses mass, which could…

…I dunno…

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3 responses to “Black Holes and White Dwarves

  1. i think we need to be concerned with more pressing issues
    http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/01/01/BA8V1AV589.DTL

  2. jacksonskepticalsociety

    Someone call my broker.

    I had gone and put all my money on 2012.

  3. cant spell broker without spelling broke

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