Subject:
Re: wind opacity model
From:
Maurice Leutenegger <maurice@milkyway.gsfc.nasa.gov>
Date:
Fri, 24 Apr 2009 02:24:53 -0400
To:
David Cohen <cohen@hven.astro.swarthmore.edu>
CC:
Emma Wollman <ewollma1@swarthmore.edu>

Hi David,

David Cohen wrote:
> Maurice,
>
> It would be great to get the new wind opacity model from you by next week so Emma could make some progress on her paper/project/final-mass-loss-rate-results prior to out group meeting on May 8.
>
Okay, I just made it. Here's what I did:

"Solar": ags2005.txt (abundances), kappa1.0.fits (opacity as function of wavelength)
with N*=5, C*=0.03, O*=0.2 : ags2005zp.txt, kappa_ags_zp.fits

I found that the proportion of CNO (ags) / CNO (new model) = 1.9, which is not totally realistic, since the CNO process conserves C+N+O, so I made two more models, labeled alt1 and alt2. The first uses the same *proportion* of C:N:O, but forces their sum to be solar. The second uses the same CNO abundances as ags2005zp.txt, i.e. such that the sum of CNO is 0.53 solar, and then forces the rest of the metals to also be 0.53 solar. So both of these alternate models have CNO / Z = solar (here Z is the sum of the abundances of metals other than CNO), but alt1 has total metallicity = solar, while alt2 has metallicity 0.5 solar.

I also attached a plot comparing opacities. You can see that alt1 has about the same opacity as ags at energies higher than the oxygen edge, as one would expect.

Oh, now that I read the rest of your email, I see that you anticipated this point... well, you can gloss over what I just wrote and use "alt1" to get the model you want.

> I'm sure you must be busy with your trapped ions, so let us know if this won't be possible.  But Emma's longest day in the lab in Tuesday, so if you can send her the new model by then, that would be great.
>
> To recap, what we're talking about is a solar metallicity (Asplund) model but with CNO abundances altered as in zeta Pup.  These are:
>
> N = 5
> O = 0.2
> C = 0.03
>
> These are relative to Asplund's solar abundances, so... they'll have to be scaled up (by 1/0.53 I believe) so that the sum of CNO is solar.
>
> By the way, I've looked at that long conference proceedings of Pauldrach's, and although he shows a very nice fit to the Copernicus and IUE spectra and says that abundances are well determined, he doesn't actually list them.  But in an email from Puls from February, he reports that Pauldrach's values are:
>
> N = 5
> O = 0.1
> C = 1.5 (is this a typo?)
That must be wrong.

>
> Does the higher C lead to a total CNO that's about solar?  Nothing was mentioned about the overall metallicity.  Maybe we shouldn't concern ourselves with Paulrdrach's determination...
>
> Thanks,
> David
Let me know if I can do anything else to help.

Maurice
opacities20090424.tar.gz
	
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