Changes between Version 17 and Version 18 of u/erica/radtimescales


Ignore:
Timestamp:
03/30/16 15:26:41 (9 years ago)
Author:
Erica Kaminski
Comment:

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  • u/erica/radtimescales

    v17 v18  
    8484
    8585So the coupling time depends on the temperature difference you want to achieve, as well as the planck opacity, density, and radiation output from the protostar. Note, I may have made dropped a factor of 4pi/c in the case it isn't absorbed by 'a'.
     86
     87''' Crossing time '''
     88
     89The time it takes a sound wave to travel from the center of the prestellar core, to the outer edge is:
     90
     91[[latex($t_{cross}=\frac{L}{C_s}$)]]
     92
     93where the sound speed for 10 K molecular gas is ~.2 km/s and L is .05 pc. This gives:
     94
     95[[latex($\boxed{t_{cross}=7.714e+12 ~s}$)]]
     96
     97or 244 KY.
     98
     99How long it takes the gas to respond to changes in the internal energy depends on the crossing time over some appropriate length scale.
     100