Changes between Version 30 and Version 31 of u/erica/radtimescales


Ignore:
Timestamp:
04/04/16 16:23:39 (9 years ago)
Author:
Erica Kaminski
Comment:

Legend:

Unmodified
Added
Removed
Modified
  • u/erica/radtimescales

    v30 v31  
    256256The time it takes a sound wave to travel from the center of the prestellar core, to the outer edge is:
    257257
    258 [[latex($t_{cross}=\frac{L}{C_s}$)]]
    259 
    260 where the sound speed for 10 K molecular gas is ~.2 km/s and L is .05 pc. This gives:
    261 
    262 [[latex($\boxed{t_{cross}=7.714e+12 ~s}$)]]
    263 
    264 or 244 KY.
    265 
    266 How long it takes the gas to respond to changes in the internal energy depends on the crossing time over some appropriate length scale.
     258[[latex($t_{cross}=\frac{r}{C_s}$)]]
     259
     260where the sound speed for 10 K molecular gas is ~.2 km/s and r=.0069 pc. This gives:
     261
     262[[latex($\boxed{t_{cross}=~33~ kyr}$)]]
     263
     264
     265How long it takes the gas density to changes in response to changes in thermal energy corresponds to the crossing time, for some appropriate length scale.
    267266
    268267''' Freefall time '''