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Could life arise around a dying star?

The views expressed are those of the author and are not necessarily those of Scientific American.

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White dwarf star Sirius B is roughly the same size as Earth (but has a mass 98% that of the sun) and is just over 8 light years away from us. Maybe we should pay it a visit... Credit: ESA and NASA

In five billion years the sun is going to blow up into a red giant, then collapse back down again into a white dwarf – a dying star roughly the same size as Earth itself. All of the solar system planets up to, and including, Earth will probably be vaporised during this stellar ballooning. We’ll be long gone (hopefully to another part of the universe, rather than gone gone).

But what will happen to Earth itself? White dwarfs stay in that state for a long time. After an initial fast cooling phase, they cool much slower and could remain stable for billions of years. Perhaps even long enough for life to arise once more in our solar system, if a planet survived, and the conditions were right…

And they could be. I have an article in this week’s New Scientist magazine about a new paper (on arXiv) by Luca Fossati at the Open University, UK, and colleagues. Fossati and his colleagues modelled what the light from a white dwarf would look like once it reached an Earthlike planet in the habitable zone around a white dwarf, and what the implications are for the possibility of life in a white dwarf star system. You’ll have to go and read the full article for the details… but I’m optimistic.

Kelly Oakes About the Author: Kelly Oakes has a master's in science communication and a physics degree, both from Imperial College London. Now she spends her days writing about science. Follow on Twitter @kahoakes.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. jtdwyer 10:15 pm 08/17/2012

    Personally, I think we’ll be doing really well if we can ever discover evidence of any life anywhere outside our own Solar system even given nice, healthy Sun-like stars – never mind any dim-watt elderly blokes!

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  2. 2. Kelly Oakes in reply to Kelly Oakes 4:22 am 08/18/2012

    jtdwyer: That would be amazing, of course. But looking around white dwarfs too has got to increase the chances of finding something, no? Plus planets transiting white dwarfs would be much easier to spot, as they’d basically eclipse the star because of its size.

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  3. 3. jgrosay 11:06 am 08/18/2012

    I guess it was discovered at least one planet that survived it’s star’s red giant phase, this probably can be calculated as the density of the expanded solar atmosphere in the phase of red giant can be predicted, and thus the possible drag the solar atmosphere may exert on the Earth orbiting the Sun during the red giant phase, and if the braking effect of this drag would take the planet out of its orbit, as orbiting bodies that slow down go far away from the central body, or the Earth would accelerate the speed in its orbit, thus falling into the Sun. If you consider the possibility of being there then, it would mean that you’re changed into a ghost, and your fate would be bad whatever it happens to the solar system.

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