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Astrophysics/average mass per particle
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Question
Hi Steve
This is a follow up question - when calculating the Jeans mass to determine when a cloud will collaspe - given by Mj= 3kTRj/2Gm - my question is what is average mass per particle for the following atoms, m?
1. neutral hydrogen atoms
2. neutral helium atoms
In case (i) I have used u = 1.661 * 10^-27 kg and
In case (ii) have used 4u = 4 * 1.661 * 10^-27 kg
Can you help
Derek
I don't answer homework question, and this isn't a follow-up to any question I've been asked before, but you might want to look up the real masses of hydrogen and helium in terms of u first, since the binding energy of helium and the isotopic abundance of hydrogen will affect your answers.
Steve Nelson
Expertise
Fusion, solar flares, cosmic rays, radiation in space, and stellar physics questions. Generally, nuclear-related astrophysics, but I can usually point you in the right direction if it's not nuclear-related or if it's nuclear but not astrophysics.
Experience
Currently a physics professor at the University of Texas of the Permian Basin. Doctoral dissertation was on a reaction in CNO-cycle fusion, worked in gamma-ray astronomy in the space science division of the naval research laboratory in the high-energy space environment branch.
Organizations
Physics professor at the University of Texas of the Permian Basin.
Education/Credentials
Ph.D. in physics, research was on nuclear fusion reactions important in stellar fusion.
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