White Dwarf Stars and Life's Building Blocks:

Discussion in 'Astronomy, Exobiology, & Cosmology' started by paddoboy, Feb 9, 2017.

  1. paddoboy Valued Senior Member

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    Dwarf star 200 light-years away contains life's building blocks
    February 9, 2017 by Stuart Wolpert

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    This artist's concept shows a massive, comet-like object falling toward a white dwarf. New Hubble Space Telescope findings are evidence for a belt of comet-like bodies orbiting the white dwarf, similar to our solar system's Kuiper Belt. The findings also suggest the presence of one or more unseen surviving planets around the white dwarf, which may have perturbed the belt to hurl icy objects into the burned-out star. Credit: NASA, ESA, and Z. Levy (STScI)
    Many scientists believe the Earth was dry when it first formed, and that the building blocks for life on our planet—carbon, nitrogen and water—appeared only later as a result of collisions with other objects in our solar system that had those elements.

    Today, a UCLA-led team of scientists reports that it has discovered the existence of a white dwarf star whose atmosphere is rich in carbon and nitrogen, as well as in oxygen and hydrogen, the components of water. The white dwarf is approximately 200 light-years from Earth and is located in the constellation Boötes.

    Benjamin Zuckerman, a co-author of the research and a UCLA professor of astronomy, said the study presents evidence that the planetary system associated with the white dwarf contains materials that are the basic building blocks for life. And although the study focused on this particular star—known as WD 1425+540—the fact that its planetary system shares characteristics with our solar system strongly suggests that other planetary systems would also.





    Read more at: https://phys.org/news/2017-02-hubble-witnesses-massive-comet-like-pollute.html#jCp
     
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  3. paddoboy Valued Senior Member

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    http://iopscience.iop.org/article/1...CBD832056345913AB8D3F530628E82.ip-10-40-1-105

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    The Chemical Composition of an Extrasolar Kuiper-Belt-Object*

    Abstract
    The Kuiper Belt of our solar system is a source of short-period comets that may have delivered water and other volatiles to Earth and the other terrestrial planets. However, the distribution of water and other volatiles in extrasolar planetary systems is largely unknown. We report the discovery of an accretion of a Kuiper-Belt-Object analog onto the atmosphere of the white dwarf WD 1425+540. The heavy elements C, N, O, Mg, Si, S, Ca, Fe, and Ni are detected, with nitrogen observed for the first time in extrasolar planetary debris. The nitrogen mass fraction is ~2%, comparable to that in comet Halley and higher than in any other known solar system object. The lower limit to the accreted mass is ~1022g, which is about one hundred thousand times the typical mass of a short-period comet. In addition, WD 1425+540 has a wide binary companion, which could facilitate perturbing a Kuiper-Belt-Object analog into the white dwarf's tidal radius. This finding shows that analogs to objects in our Kuiper Belt exist around other stars and could be responsible for the delivery of volatiles to terrestrial planets beyond the solar system.

     
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  5. paddoboy Valued Senior Member

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    OK, what I immediatly thought was in around 3 billion years? hence, when our Sun starts to bloat and enter the red giant phase.
    By that time of course, we should be well spread out amongst the solar system and stars....at least one would hope so!

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    Eventually the Giant red Sun will swallow the inner terrestrial planets of Mercury, Venus and probably also Earth.
    So unless some catastrophic event has not in the meantime had any significant effect, humanity may well survive still within this solar system, say on Mars, or even possibly the Galilean Satellites of Jupiter, which are all thought to have water, other than Io.
    Also a WD star can maintain heat for many billions of years, so we could still very well be calling our system home for a long while yet.

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    ps: When a WD finally gives up all its heat, we will have left nothing but a black cinder, and as yet no known WD has yet reached that stage....at least none have ever been observed.

    In other words, as indicated by the article and paper, viable life bearing systems around WD stars, are possible.
     
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