[mesa-users] Puzzled about deuterium output

[Bill Paxton]

Hi Mike,

Interesting question -- and I don't have a quick answer.
Let's see if anyone on mesa-users can help us on this one.

Cheers,
Bill


On May 13, 2015, at 1:52 PM, Michal Simon wrote:

> Hi Bill,
> 
> I've successfully run models with "pp extras" for stars btwn 0.1 and 1.0 Msun.
> I now want to know how the D/H abundance depletes and included the
> "average h1" and "average h2" columns in the history_columns.list file. 
> 
> As a test I ran a 1 msun model.  As expected the D abundance becomes
> smaller by more than a factor of a 100 by ages of a few X 10^5 years.  But,
> the D/H values puzzle me, hence this msg.
> 
> At early times, say a fewX10^3 yrs history.data reports
> 
> average h1    = 0.69999
> average h2   =  3.69 X10^-5
> 
> That gives D/H ~ 5 X 10^-5, more than twice as large as expected because
> in   /chem/data/isotopes.data
> 
> I read for H1  8.0713  and for H2 = 13.1357.  Interpreting these as logs implies
> D/H 8.6 X 10^-6.....more or less ok.  In Paxton et al 2011 you write that for
> purposes of Fig. 5 you used 2 X 10^-5 to match Chabrier et al.   
> 
> Am I misinterpreting the numbers and there is no disagreement?  Is approx
> 9X10^-6 the default D/H abundance MESA uses?
> 
> Cheers, and thanks again in advance,
> Mike
> 
> 
> 
>