[mesa-users] Creating a gamma Dor model

[Hideyuki Saio]

Hi Rich,

I have obtained models for three slowly rotating gamma Dor stars so far.  Frequencies of these models fit reasonably well with observed frequencies, but I didn’t pay attention to the stability.  The parameters of these models are

    M      X       Z     log Teff    log L    T(bottom CZ)       
  1.46  0.65  0.01    3.842     1.04       51 kK    ——  KIC 11145123
  1.45  0.724 0.01   3.821     0.85       185 kK  ——  KIC 9244992
  1.90  0.72  0.014  3.835     1.31        51 kK   ——  KIC 7661054

 I used some versions of MESA with activating atomic diffusion and radiative turbulence as
       radiation_turbulence_coeff = 1.  
       do_element_diffusion = .true. 
 
Just for your information.
Hideyuki
           

   
> 2016/07/14 5:03、RICHARD H D TOWNSEND <townsend at astro.wisc.edu> のメール：
> 
> Hi folks —
> 
> I’m interested in creating a models for gamma Dor stars, in which gravity modes are unstable due to convective flux blocking. I’ll be using GYRE to do the stability calculations; I appreciate that the convection-pulsation interaction probably needs a more-sophisticated approach than GYRE’s current method (convective freezing), but for now GYRE should suffice.
> 
> My first step is attempting to reproduce some of the gamma Dor models presented in Warner, Kaye & Guzik (2003, ApJ 593, 1049). However, try as I might, I seem to end up with models that don’t have the (relatively) thick outer convection zone reported by Warner et al.
> 
> As a specific example, I attach a MESA inlist which aims to reproduce the M=1.55 Msun model reported in Table 1 of Warner et al. Running this inlist with MESA 8118 results in a final model with the following properties:
> 
> Teff = 6927 K
> L/Lsun = 6.82
> Age = 1.049 Gyr
> 
> This model is somewhat cooler than the model reported in Warner et al (their Teff = 6965K), but the difference is small. The luminosity matches exactly, and the age is close (their age = 1.076 Gyr). So, it looks like I’m in the right ballpark.
> 
> However, when I look at the internal structure of the model, I’m struck by the fact that the inner edge of the envelope convection zone is at T ~ 63 kK (logT ~ 4.75), rather than the ~ 240 kK (logT ~ 5.4) reported by Warner et al. Here’s a plot of the radiative vs total flux, as a function of temperature, which demonstrates this:
> 
> <figure_1.png>
> 
> Indeed, I find that to get the convection zone(s) to extend to deeper layers, I have to allow the star to be significantly cooler and more evolved.
> 
> Since I’m not all too familiar with gamma Dor stars, I’m likely making a stupid mistake in my inlist file. Can anyone suggest what might be the problem?
> 
> Many thanks,
> 
> Rich
> 
> <inlist><profile_columns.list>
> 
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