[Mesa-users] The color and V band mag of the current Sun and solar-type stars

[Rob Farmer]

You can always provide your own file of bolometric corrections if you think
they will do a better job of fitting your objects of interest.

See http://mesa.sourceforge.net/star_job_defaults.html#Color_Files

Rob

On Mon, 7 Oct 2019 at 15:32, Aaron Dotter via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> Hi,
>
> Does the MESA colors module, independently of the evolutionary track, give
> a sufficiently accurate solar color?  (Keeping in mind that to measure the
> color of the sun is notoriously difficult because it is so bright.)
>
> It sounds like, for you, the answer to question 2 is No.  You cannot "fix"
> this issue with additional physics in the evolutionary track.  The issue
> lies within the colors data file used by the MESA colors module.
>
> To make further progress, you would need to access an independent module
> for calculating synthetic magnitudes (or calculate them yourself).  There
> are a handful of these available.
>
> How important is it that you are able to match B-V to better than 0.03?
> There are a variety of small details that matter at this level . . .
>
> Cheers,
> Aaron
>
>
> On Sat, Oct 5, 2019 at 4:50 PM M Sun <sunmeng1118 at gmail.com> wrote:
>
>> Hello Aaron,
>>
>> Thank you very much for your suggestion! I've tested with working in
>> simplex_solar_calibration directory and could produce a model close to the
>> current Sun. When I checked back the (B - V) mag, it still bluer than
>> observation about 0.03 mag. Here I attach the HR diagram, the color
>> magnitude diagram and R vs Age plot when running solar calibration
>> simulations. The initial conditions and the controls are attached as well.
>>
>> The stars I am working on have a different metallicity, the (B - V) mag
>> disagreement between simulation and observation is bigger than this
>> (although L and Teff are in a good agreement, there is a 0.06 mag of (B -V)
>> between model and data). I am wondering if I forget some important physics
>> when computing the colors. Or does anyone have this issue before and how do
>> we fix it, especially near ZAMS and MS phase? Thanks!
>>
>> cheers,
>> Meng
>>
>> On Fri, Oct 4, 2019 at 3:05 PM Aaron Dotter <aaron.dotter at gmail.com>
>> wrote:
>>
>>> Before checking the magnitudes, I recommend you try to reproduce the
>>> solar Teff, L, and R.  See, for example, the simplex_solar_calibration in
>>> the test suite.
>>>
>>> Independently, check whether or not the mesa/colors module is able to
>>> reproduce the solar colors for the solar metallicity, Teff and log(g).
>>> This can be done irrespective of the solar evolutionary track; you can
>>> simply call the colors module with the solar parameters as input.
>>>
>>> On Fri, Oct 4, 2019 at 3:54 PM M Sun via Mesa-users <
>>> mesa-users at lists.mesastar.org> wrote:
>>>
>>>> Hello MESA users,
>>>>
>>>> Recently I am trying to produce some evolutionary tracks for solar-type
>>>> stars in an open cluster. The luminosity, effective temperature agree with
>>>> the observation very well. However, when I check the color magnitude
>>>> diagram, those solar-type stars seem much bluer than observation near the
>>>> main sequence phase.
>>>>
>>>> Then I tried to make a track for the current Sun with different initial
>>>> metallicities and mixing length factors (still in the proper range I
>>>> think), it is bluer than I expected as well. Here I attached my plot. The V
>>>> mag and B mag I used for the current Sun (shown in the red star in the
>>>> plot) are --
>>>> solar_abs_V = 4.83
>>>> solar_abs_B = 5.48
>>>> The open circles indicate the age at 1, 2 ... 6 Gyrs from the
>>>> bottom right to top left. I terminate the simulations after 6 Gyrs.
>>>>
>>>> I am using MESA 12115 in the test_suite working directory
>>>> "1M_pre_ms_to_wd". Here I attached my inlists and please let me know if you
>>>> need more information. The atmosphere table I used is 'photosphere'. Many
>>>> thanks!!
>>>>
>>>> cheers,
>>>> Meng
>>>> --------------
>>>> Meng Sun
>>>> University of Wisconsin Madison
>>>> https://sunmeng1118.wixsite.com/mysite
>>>> _______________________________________________
>>>> mesa-users at lists.mesastar.org
>>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>>
>>>>
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