At the end of their lives, stars like the Sun left behind a remnant white dwarf star called . In the process, it is likely that Earth-like planets exist around it are completely incinerated. However, white dwarfs are a very interesting scenario for the future of life in the universe. The fusion stage of the stars, in which we live, occupy a small fraction of the life of the universe (supposedly infinite). In contrast, white dwarfs will shining billions of years after it has been off the last star . It is possible that the fate of living beings depend on the existence of planets around these stars.
A white dwarf compared to the Earth.
As we discussed in a previous post so far has not uncovered any exoplanet around a white dwarf. These planets are most likely worlds second or third generation, ie, formed from planetary debris generated during the red giant phase. In any case, life could exist on these worlds? This is precisely what has been explored in a recent article Eric Agol of the University of Washington.
When stars as small (the size of Earth), the habitable zone around a white dwarf would be located very near the same, between 0.75 and 3 million miles to cool dwarfs (with a surface temperature of 5000 K) and 0.4 to 0.9 times the Sun's mass white dwarfs are great pieces of degenerate matter without an internal power source. Over time, a looooong time, be cooled to lead to a black dwarf. However, the universe is not even old enough to be able to form a black dwarf. The habitable zone around a white dwarf will shrink as the star cools, but still we are talking about large time scales. For example, a planet a million miles from a dwarf could stay up to eight billion years in the habitable zone, a time equivalent to the life of the Sun
habitable zone around a white dwarf as a function of distance and life / light (Eric Agol).
Possible appearance of curves light of the eclipses of habitable planets around white dwarfs (Eric Agol).
density probability of detection of planets around white dwarfs. The transit method favored in this case the detection of planets the size of the Earth (Eric Agol).
A planet in the habitable zone of a white dwarf could completely obscure the star as seen from Earth. This fact makes these stars in potential targets of the transit method to detect exoplanets, but it will not be easy.
Paradoxically consider the possibility the existence of habitable planets around dead stars. But it is possible that one day, our distant descendants refuge in these worlds while the rest of the world goes around.
More information:
A white dwarf compared to the Earth.
As we discussed in a previous post so far has not uncovered any exoplanet around a white dwarf. These planets are most likely worlds second or third generation, ie, formed from planetary debris generated during the red giant phase. In any case, life could exist on these worlds? This is precisely what has been explored in a recent article Eric Agol of the University of Washington.
When stars as small (the size of Earth), the habitable zone around a white dwarf would be located very near the same, between 0.75 and 3 million miles to cool dwarfs (with a surface temperature of 5000 K) and 0.4 to 0.9 times the Sun's mass white dwarfs are great pieces of degenerate matter without an internal power source. Over time, a looooong time, be cooled to lead to a black dwarf. However, the universe is not even old enough to be able to form a black dwarf. The habitable zone around a white dwarf will shrink as the star cools, but still we are talking about large time scales. For example, a planet a million miles from a dwarf could stay up to eight billion years in the habitable zone, a time equivalent to the life of the Sun
habitable zone around a white dwarf as a function of distance and life / light (Eric Agol).
Possible appearance of curves light of the eclipses of habitable planets around white dwarfs (Eric Agol).
density probability of detection of planets around white dwarfs. The transit method favored in this case the detection of planets the size of the Earth (Eric Agol).
A planet in the habitable zone of a white dwarf could completely obscure the star as seen from Earth. This fact makes these stars in potential targets of the transit method to detect exoplanets, but it will not be easy.
Paradoxically consider the possibility the existence of habitable planets around dead stars. But it is possible that one day, our distant descendants refuge in these worlds while the rest of the world goes around.
More information:
- Transit surveys for Earths in the habitable zones of white dwarfs , Eric Agol (arXiv, March 17, 2011).
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