Saturday, December 17, 2016

Solution to Suggested Comprehension Ex. For Part 1 (Construction of a Star)

From the next to last U,V values given in the model table (i.e. at r/R = 0.262), confirm the values for: Mr/M, log P and log (rho) ,  i.e.   log   r .  Note the pressure at given Mr  is given by :

P   =      G  r Mr/ V r


We have: U = 2.006 and V = 2.829

Mr/M = 0.395 =  1.568  x 1033  g

density:  log (rho) =  log   r 


 r   =     UMr/4p r3

=  [(2.006) (1.568  x 1033  g)]/ 4p (2.567  x 1010  cm) 3

r  =   14.80  g/ cm 3        log   r  = 1. 1703


Pressure:

P   =      G  r Mr/ V r

=  [(6.67 x  10-8 dyne-cm 2/ g.2)  (14.80  g/ cm 3 )(1.568  x 1033  g)/   (2.829)(2.567  x 1010  cm)

P   =  2.131  x 1016    dynecm 2


log P   =   16.3286

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