[Mesa-users] Stars older than universe

[Fahri Aliçavuş]

Hello Gökhan,
I think Rob is right, you should use the Binary module anyway. and you have
to consider effects such as rotation, magnetic braking. You should also
consider orbital evolution because in the last case they have a period of
about 1 day and the components affect each other.

For the situation, here are some  possibilities:

-Stars may be a pre-main sequence.

-The system may have started its evolution with a high eccentricity, in
which case mass transfer may occur even if it is detached (in some phases).

- You can try different Z's. you may also consider rotation (you used zero)

-You should also consider that the radius error in the article is given
around 13%.

However, if you compare your results with Mist (
http://waps.cfa.harvard.edu/MIST/interp_tracks.html), the age of the star
should be around 2-3 Gyr (if it is a main-sequence star) for the radius of
the star. So, you probably make a mistake somewhere while producing models.

Cheers,
Fahri

Gökhan Yücel <gokhanyucel at akdeniz.edu.tr>, 14 Ara 2020 Pzt, 10:50 tarihinde
şunu yazdı:

> Hello everyone,
>
> I have been doing evolution of binary stars that their stellar parameters
> are well known until mass transfer starts. To do that, I simple evolve
> single stars until they reach to their current radii and save their models.
> After that I use binary mode to evolve them. I have been successful to do
> that for a while but I have encountered some sort of situations while doing
> a single star evolution. Some very low mass stars, M spectral type
> specifically, has an age more than universe itself according to models. I
> believe something is wrong in here. I have checked the parameters and how
> they had been calculated and there is nothing in this area. This has
> happened some other stars, all of them are very late types, too.
>
> M = 0.489 Msun, R = 0.453 Rsun
>
> I attached the files. I am using mesa version of "r12115" and SDK version
> of "20190830".
>
> What am I doing wrong?
>
> Sincerely,
> Gökhan_______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>
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