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Jeans instability

by Cmertin
Tags: instability, jeans
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Nov3-12, 04:01 PM
P: 58
I'm trying to understand all the properties of the Jeans instability, the Jeans mass and the Jeans length. I understand the mathematics behind it, though not all the variables. There is a [itex]m_{H}[\itex] or I've also seen it as [itex]m_{p}[\itex] in the Jeans length and Jeans mass. The formula is as follows:

[itex]M_{J}=(\frac{5k_{B}T}{Gμm_{H}})^{1.5}(\frac{3}{4\Pi\rho_{0}})^{. 5}[\itex], I know that μ is the average molecular mass.

Can someone help me understand this please? I'm a bit confused. I tried looking at the units, though couldn't figure it out.

Also, another question about it: Does it work for all masses of ISM? From what I picked up in class, most things don't work for very large objects in astro, and they need more "fudge factors" to work. Is that the same for the Jeans instabilities?
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Yuu Suzumi
Nov14-12, 10:03 AM
Yuu Suzumi's Avatar
P: 16
Dear Cmertin,

H stands for hydrogene, p for proton. The nass measured in that unit is [itex]\mu[/itex]!

All the best,

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