[Mesa-users] Issues Resolving Pulsations for a Second-Crossing Cepheid

[Radek Smolec]

Hi Ewen,

wt., 17 cze 2025 o 17:11 Ewen Francis MacKenzie Whyte <
efmackenziewhyte at mta.ca> napisał(a):

> Hi Radek,
>
>
>
> I actually did try some RSP on these models, I had a script set up that
> would read in the necessary values from a history file and build the
> initial RSP model from those parameters. Unfortunately, all the periods
> were damped. Do you know why this might be?
>
What were the reported linear  growth rates for these models; positive? You
can find them in LINA_period_growth.data  file (third column) in your LOGS
directory. If you have selected models based on some of the literature
edges of the instability strip, the models may not actually be inside the
IS but close to it (hence the damped pulsations), so check this. If the
values are negative, try to go further along the evolutionary track. If the
reported values are positive and the pulsations have been damped, share the
inlist and the MESA version.
Best wishes,
Radek


>
>
> Best,
>
>
>
> Ewen
>
>
>
> *From: *Radek Smolec <smolec at camk.edu.pl>
> *Date: *Tuesday, June 17, 2025 at 11:52 AM
> *To: *Ewen Francis MacKenzie Whyte <efmackenziewhyte at mta.ca>
> *Cc: *mesa-users <mesa-users at lists.mesastar.org>
> *Subject: *Re: [Mesa-users] Issues Resolving Pulsations for a
> Second-Crossing Cepheid
>
> You don't often get email from smolec at camk.edu.pl. Learn why this is
> important <https://aka.ms/LearnAboutSenderIdentification>
>
> Dear Ewen,
>
>
>
> For most applications I can think of an envelope model of Cepheid created
> with RSP should be fine. Then you are not using a full structure model from
> MESA evolutionary run. Just record the physical parameters, M, L, Teff, Y
> and Z and give these as input to RSP, which will create a homogeneous
> envelope model and then evolve the model from initial perturbation to full
> amplitude pulsation. See MESA fifth instrument paper and rsp_Cepheid test
> suite.
>
> Best wishes,
>
> Radek
>
>
>
> pon., 16 cze 2025 o 21:59 Ewen Francis MacKenzie Whyte via Mesa-users <
> mesa-users at lists.mesastar.org> napisał(a):
>
> Hi all,
>
>
>
> My goal is to evolve a 10 solar mass Cepheid to the blue loop and save the
> model when it is close to the blue edge of the instability strip during the
> second crossing. At that point I would like to drop the timestep to a few
> hours and start generating a light curve to resolve the Cepheid’s
> pulsations.
>
>
>
> Thus far I have had no success in this endeavour. I have tried many
> different solutions like increasing the number of zones, attempting RSP
> analysis, lowering the star’s mass, using a finer temporal resolution, and
> so on. I am happy to provide inlists that I used if that helps.
> Unfortunately, none of my results have pointed to a pulsating Cepheid.
>
>
>
> I figured you all might have some new ideas for me to try, or controls
> that I am missing. Let me know your thoughts!
>
>
>
> Sincerely,
>
>
>
> Ewen
>
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