[mesa-users] Vink_wind_eta

Tue May 26 16:34:09 EDT 2015

Hi all,

I think this implementation works nicely for massive stars (MS O vs. RSG
vs. WR), but this means you won't be able to separately choose (modest) RGB
and (more aggressive) AGB winds since both would fall under wind_cool. You
could always use run_star_extras but the RGB-AGB distinction is significant
enough that I think they deserve separate categories.

Cheers,
Jieun

On Tue, May 26, 2015 at 4:09 PM, Zsolt Keszthelyi <
Z.Keszthelyi at campus.lmu.de> wrote:

> Hi,
>
> I was about to suggest the same thing! A further support is that this is
> basically already implemented in the 'Dutch wind'.
>
> Maybe 10 - 12 kK would be a good limit to distinguish between 'hot' and
> 'cool'.
>
> Cheers,
>  Zsolt
>
>
>
>
> > Von: Mathieu <mathren90 at gmail.com>
> > An: mesa-users at lists.sourceforge.net
> > Kopie:
> > Datum: Tue May 26 22:03:06 CEST 2015
> >
> > Hi everyone,
> >
> > since the wind mass loss is not directly connected with the burning
> > stage in the core, I would suggest avoiding to name the different wind
> > options according to the nuclear processes in the core.
> > It seems a bit confusing to me.
> >
> > Most of the mass loss algorithms apply in a given temperature range, so
> > I would suggest using something like:
> >
> >   - wind_hot
> >   - wind_cool
> >   - wind_WR
> >
> > and use a condition on the effective temperature (and surface hydrogen
> > abundance for the WR wind scheme) to switch between different rates.
> > This should match more consistently the physics of the wind driving
> > (which depends on the radiative flux, parametrized in terms of the
> > effective temperature), and also the way mass loss algorithms are
> > derived either from observations (e.g. de Jager, Nieuwenhuijzen, and van
> > Loon rates), or from numerical simulations of the wind (as in the Vink
> > case).
> >
> > Best wishes,
> >
> > Mathieu
> >
> > On 05/26/2015 07:32 PM, Bill Paxton wrote:
> > > Thank Ehsan.   And anyone else who'd like to add a comment, please do.
> > >
> > > bill
> > >
> > >
> > >
> > > On May 26, 2015, at 10:30 AM, Ehsan Moravveji wrote:
> > >
> > >> Hi Bill, hi all,
> > >> I think a reasonable naming that also takes care of generality could
> be something
> > like mass_loss_h_burning, and mass_loss_he_burning. Then whether or not
> one deals
> > with OB stars or an RGB, the former applies, and after the core He
> ignition, the
> > latter enters the stage.
> > >> Just a suggestion …
> > >>
> > >> Cheers
> > >> Ehsan.
> > >>
> > >>> On 26 May 2015, at 17:57, Bill Paxton <paxton at kitp.ucsb.edu> wrote:
> > >>>
> > >>> Thanks --- that is very helpful.  it looks like we're still using a
> scheme from
> > the infancy of mesa when there were only a few options, but now it isn't
> a good fit
> > for the range of options that have been added since then.  time for a
> cleanup.
> > >>>
> > >>> the RGB/AGB split was meant to provide a simple way for users to
> select different
> > wind schemes for different stages of evolution.
> > >>> and since the scheme could change on the fly, there needs to be a
> way to change
> > the wind_scaling_factor too.
> > >>> that is taken care of by providing separate values of scaling factor
> for the
> > different kinds of winds.
> > >>>
> > >>> I can easily do the renaming to replace "eta" by "scaling factor"
> while keeping
> > different scaling factors for different types of wind.
> > >>>
> > >>> Do you have suggestions for a way to replace the crude RGB/AGB by
> something better?
> >  RGB/AGB/OB?  or what?
> > >>> and please include precise details of the partitioning so that I can
> translate
> > it into code!
> > >>>
> > >>> Thanks again,
> > >>> Bill
> > >>>
> > >>>
> > >>>
> > >>>
> > >>> On May 26, 2015, at 3:26 AM, Zsolt Keszthelyi wrote:
> > >>>
> > >>>> Hi Bill,
> > >>>>
> > >>>> thanks for your reply.
> > >>>>
> > >>>> I think the issue is that eta is used in different contexts with
> different meanings
> > in the literature.
> > >>>>
> > >>>>
> > >>>> 1. In the context of RGB / AGB stars (Reimers 1975, Blöcker 1995)
> eta is a scaling
> > factor to match observed mass loss rates with their empirical mass loss
> formulas.
> > >>>>
> > >>>>
> > >>>> 2. On the other hand, in the context of WR stars (Cassinelli 1991
> and references
> > therein) eta was introduced with a physical meaning, to describe the
> wind with the
> > ratio of stellar wind momentum flux and the photon momentum flux, eta =
> Mdot * vinf
> > / (L / c).
> > >>>>
> > >>>> This eta is used in the context of OB stars (e.g., Lamers &
> Leitherer 1993,
> > Puls et al. 1996) as the performance number.
> > >>>>
> > >>>>
> > >>>>
> > >>>> Even though the idea of eta as a scaling factor is stated (and
> used), a user
> > was looking for eta in the Vink paper, so that is why I think calling it
> simply 'wind_scaling_f
> > actor' might make it easier for the users.
> > >>>>
> > >>>>
> > >>>> Also my understanding is that you must set either 'RGB_wind_scheme'
> or 'AGB_wind_scheme'
> > to apply one of the wind recipes, however the Kudritzki, Vink (OB) and
> Nugis & Lamers,
> > Gräfener & Hamann (WR) prescriptions are not valid for these stars. This
> might also
> > be a source of confusion since in a previous email the vink_wind_eta and
> RGB mass
> > loss was mentioned together.
> > >>>>
> > >>>>
> > >>>> I hope this is helpful.
> > >>>>
> > >>>> Cheers,
> > >>>>
> > >>>> Zsolt
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>
> > >>>>> Von: Bill Paxton <paxton at kitp.ucsb.edu>
> > >>>>> An: Zsolt Keszthelyi <Z.Keszthelyi at campus.lmu.de>
> > >>>>> Kopie: mesa-users at lists.sourceforge.net users <
> mesa-users at lists.sourceforge.net>
> > >>>>> Datum: Tue May 26 06:46:15 CEST 2015
> > >>>>>
> > >>>>>
> > >>>>> On May 23, 2015, at 4:25 AM, Zsolt Keszthelyi wrote:
> > >>>>>
> > >>>>>> It's a little bit unlucky nomenclature though, since in stellar
> wind physics
> > the
> > >>>>> eta is the so-called wind efficiency / performance number and has
> nothing to
> > do with
> > >>>>> a numerical scaling factor. (It might be useful to change it in
> the next version.)
> > >>>>>
> > >>>>>
> > >>>>> Hi,
> > >>>>>
> > >>>>> In star/defaults/controls.defaults we describe the various etas
> like this for
> > Reimers
> > >>>>> and Blocker winds:
> > >>>>>
> > >>>>>        !### Reimers_wind_eta
> > >>>>>        ! Parameter for mass loss by Reimers wind prescription.
> > >>>>>        ! Reimers mdot is `eta*4d-13*L*R/M` (Msun/year), with L, R,
> and M in
> > solar
> > >>>>> units.
> > >>>>>
> > >>>>>        !### Blocker_wind_eta = 0
> > >>>>>        ! Parameter for mass loss by Blocker's wind prescription.
> > >>>>>        ! Blocker mdot is `eta*4.83d-9*M**-2.1*L**2.7*4d-13*L*R/M`
> (Msun/year),
> > >>>>>
> > >>>>> Having stated that idea twice, we just hope the reader will make
> the leap to
> > understand
> > >>>>> that they work similarly for the remaining kinds of winds.
> > >>>>>
> > >>>>> So we use "parameter for mass loss" where you would use "wind
> efficiency /
> > performance
> > >>>>> number".
> > >>>>>
> > >>>>> In practice of course it is a numerical scaling factor for the
> strength of
> > the wind.
> > >>>>> At least it looks like that to me.  And it does that in the code.
> > >>>>>
> > >>>>> If I'm missing something important about the role of eta in
> stellar wind physics,
> > >>>>> please educate me.
> > >>>>>
> > >>>>> Thanks,
> > >>>>> Bill
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>>
> ------------------------------------------------------------------------------
> > >>>>> One dashboard for servers and applications across
> Physical-Virtual-Cloud
> > >>>>> Widest out-of-the-box monitoring support with 50+ applications
> > >>>>> Performance metrics, stats and reports that give you Actionable
> Insights
> > >>>>> Deep dive visibility with transaction tracing using APM Insight.
> > >>>>> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
> > >>>>>
> > >>>>> _______________________________________________
> > >>>>> mesa-users mailing list
> > >>>>> mesa-users at lists.sourceforge.net
> > >>>>> https://lists.sourceforge.net/lists/listinfo/mesa-users
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>
> > >>>
> ------------------------------------------------------------------------------
> > >>> One dashboard for servers and applications across
> Physical-Virtual-Cloud
> > >>> Widest out-of-the-box monitoring support with 50+ applications
> > >>> Performance metrics, stats and reports that give you Actionable
> Insights
> > >>> Deep dive visibility with transaction tracing using APM Insight.
> > >>> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
> > >>> _______________________________________________
> > >>> mesa-users mailing list
> > >>> mesa-users at lists.sourceforge.net
> > >>> https://lists.sourceforge.net/lists/listinfo/mesa-users
> > >
> > >
> ------------------------------------------------------------------------------
> > > One dashboard for servers and applications across
> Physical-Virtual-Cloud
> > > Widest out-of-the-box monitoring support with 50+ applications
> > > Performance metrics, stats and reports that give you Actionable
> Insights
> > > Deep dive visibility with transaction tracing using APM Insight.
> > > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
> > > _______________________________________________
> > > mesa-users mailing list
> > > mesa-users at lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/mesa-users
> >
> >
> >
> ------------------------------------------------------------------------------
> > _______________________________________________
> > mesa-users mailing list
> > mesa-users at lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/mesa-users
> >
>
>
> ------------------------------------------------------------------------------
> _______________________________________________
> mesa-users mailing list
> mesa-users at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/mesa-users
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20150526/c170e0e3/attachment.html>