[Mesa-users] about the decay rates of al26, al26-1 and al26-2

Ertao Li ertaolee at gmail.com
Tue Feb 6 09:31:16 EST 2018

Dear all,

I am trying to do some research about the abundance of Al26 by using the MESA. I have some questions about the decay rates of al26, al26-1 and al26-2, because they confuse me. Can anyone help please?

Firstly, I noticed that the decay rates (stored in cache/*.bin) of  al26, al26-1 and al26-2 are constant and do come from $MESA/data/rates_data/JINA_reaclib***. But, from the MESA instruction paper  apj 220 (2015) 15, page 32:
\The rates module provides weak reaction rates for
\hundreds of isotopes. By default, when atoms are fully ionized,
\these rates are based (in order of precedence) on the tabulations
\of Langanke & Martínez-Pinedo... 

What I think is that MESA only creates the decay rates from JINA but doesn't use them, MESA uses the  $MESA/data/rates_data/weakreactions.tables to get the decay rates but doesn't save them.  Am I correct?

Secondly, the partition functions in $MESA/data/chem_data/isotopes.dat should affect the decay rates of al26, al26-1 and al26-2. However, after I changed the partition functions, the decay rates do not change at all. Does MESA use the partition function?

Thirdly, why is the partition function of al26-1 and al26-2 always equal 1.0?

Lastly, how can I include the excitation and de_excitation between al26-1 and al26-2?
Thanks in advance,

Er-Tao Li(李二涛)
Assistant Professor                                                              Visiting Scholar
College of Physics & Energy                                                 Konkoly Observatory
Shenzhen University                                                             Hungarian Academy of Sciences           
Nanhai Ave 3688, Shenzhen, Guangdong, P.R.China, 518060   H-1121 Budapest, Konkoly Thege Miklós út 15-17
Tel: +86-755-26536232. Fax: +86-755-26534374                    Ph: +36 70 25 9 8316
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