Recent content by beee

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    Why does deuterium burn at lower temperature than H

    Makes perfect sense, thank you. As I see now, creating 2H is one of the steps in p-p chain of 1H fusion, and rate limiting one at that. If you already have 2H, the fusion can take place at much lower temperatures.
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    Why does deuterium burn at lower temperature than H

    In general, nuclear fusion happens at a higher temperature for heavier elements. In my astrophysics class we derived an equation for probability of nuclear reactions, and without quoting it exactly, it boils down to have this probability proportional to exp(-mrZ1Z2), where mr is the reduced mass...
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    Decay chain of radioactive isotopes

    Thank you, Bateman equations are exactly what I was looking for!
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    Atmospheric C14 is measured permil Permil of what?

    I believe it is usually given as a ratio to stable C12. As for "per thousand" vs "per million", judging by the Wiki article referenced by tiny-tim, it is "per thousand". Another pointer to that is that in the tabulated data provided includes another quantity which is expressed as "ppm" which is...
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    Decay chain of radioactive isotopes

    How can I efficiently calculate the amount of material decayed after a specific time in a two-step decay chain? In my specific example, I have 56Ni -> 56Co -> 56Fe. The half life of the first process is 6.1 days, the second - 77.7 days. How can I accurately calculate the amount of 56Fe that...
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    Astrophysics: pressure in a supernova as in explodes

    This is called sleep is good for you! The next morning I redid my calculation and got something in that range - turns out I was accidentally multiplying by Boltzmann constant instead of dividing. :)
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    Astrophysics: pressure in a supernova as in explodes

    Homework Statement In its early phase, the supernova is an explosion within the star’s own envelope; about half the energy is thermal and half is kinetic. Estimate the ratio of radiation pressure to gas pressure in the star at the moment the shock reaches the surface. (Not in the pre-explosion...
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    Thermal/Statistical Physics Paramagnet

    I guess the only thing to do is take a limit of M(B, T, N) as T goes to zero. That seems to work perfectly and agrees with common sense in the end.
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