Tzitlaly,

Sorry for the delay, but I've finally had a chance to look over your presentation (version you emailed to me on August 7.  (Let me know if you've got a more recent version).   I've put the version I'm looking at here:

http://astro.swarthmore.edu/~cohen/projects/Tzitlaly/ 

just to be clear about which version I'm commenting on. 

Before I start, I wanted to remind you that you have to submit a 4 page paper on your research by October 1; you should plan on sending me a draft for feedback by September 18.  There's information about the paper here: 

http://astro.swarthmore.edu/knac/symp2010_guidelines.html

You can take figures directly from your talk, and treat the slide text as an outline for your paper, fleshing it out with additional words. 

OK, here are my comments on your talk: 

General: 

It looks very good.  

The notes you have to go along with each slide will be useful; in some cases, there's more information than you'll want to actually say (e.g. information about the spectrograph on slide #3 -- though if you mention at the end of your talk that we'd like to make follow up spectroscopic observations on our B star in the near future, maybe it would in fact be good to at least mention the new spectrograph early on in the talk). 

On slide #3, rather than quoting a limiting magnitude (which is dependent on exposure time in any case), how about quoting the exposure time you typically used for 176582, its magnitude, and the S/N (we can talk about this, but it's related to the size of your photometric error bars) you typically achieved. 

For slide #4, I think I've got a photo of you (and Jean) in the control room. 

Slide #5: you show a sample light curve and talk about turning raw observations into a light curve.  Good.  I think the one you're showing is U Cep.  You should state that on the slide (and maybe be prepared to briefly mention that it's an eclipsing, mass-transfer binary and you're showing the ingress to an eclipse).  You could also/instead show one of the extrasolar planet transit light curves.  

Slide #6: you're showing what B stars are.  Maybe have an arrow pointing to the B star region on the HR diagram (and maybe another one to the Sun, for comparison). 

Slide #7 shows how magnetic B stars channel their winds to form a magnetosphere, which rotates around the star, blocking varying portions of the photosphere and therefore leading to photometric variability.  Great.  This is a key slide for your talk.   I think you'll want to stress that this model predicts rotationally modulated variability.  (I can ask Rich for an additional movie that shows the magnitude vs. phase along with the simulation.) 

Slide #7a: in your notes for slide #7, you mention another Bp star with rotational modulation.  I think sigma Ori E, the prototype of the class, is a good example.  How about adding a slide right after slide #7 that shows sigma Ori E's light curve (from one of Townsend's papers)? 

Slide #8: This suite of models showing how the light curves vary with obliquity and viewing angle is very important, as it basically connects the theoretical model to what we're actually observing.  My main suggestion is that the figure is hard to read -- the words; the axis labels, especially.  You can add your own labels to the slide ("magnetic axis obliquity" and "inclination angle") in a big typeface.  People will be confused about what this image is showing - it looks complicated.  I don't think you should - or that you'd have the time to - explain the physics in detail.  But you should be ready to say something along the lines of, "the way that the photosphere's light is blocked by the magnetosphere, depends on the rotational velocity, the obliquity, and the inclination angle.  Here are a suite of model light curves for various combinations of parameters.  By measuring the photometric variability of Bp stars we're studying, we can constrain these important parameters." 

Slide #9 shows the Hipparcos photometry.  Here you can stress again that the shape of such a light curve can tell us about the star's parameters that affect the properties of the magnetosphere.  You can state the ways that your own observations will improve on the Hipparcos data  (confirm period, look for color variations). 

Slide #10 shows one of your own observations.  I would present this slide as an example of your own data, and not as the slide where you state your results.  You could mention the challenge of doing accurate enough photometry without too many comparison stars of similar brightness (have you already listed the magnitude of HD 176582?  If not, you should here).  You should label the star itself in the image.  You can talk about the challenge of doing accurate photometry from night to night. 

Next, I think you should put together a slide with preliminary light curves in a couple of different filters. Plus, have you tried folding your own data on the known period?  Once you do this, we can see what additional data we'd like to have, and I can make some more observations for you. 

Part of your conclusions could involve ruling out various parts of obliquity - inclination angle parameter space (based on the diagram on slide #8 plus the way your - or even just the Hipparcos - light curve looks; or doesn't look - in other words, you might not be able to say which model, exactly, IS the best, but you can probably say that lots of them definitely don't look like the data and are thus ruled out). 

Note that with the 1.58 day period more or less known, if we can find estimates of the star's radius and mass in the literature, then we can estimate its angular velocity as a fraction of the critical velocity (which is the other free parameter of Townsend's model).  The suite of models you show in slide #8 is for one particular value of this parameter (w/w_c), but is that value the one that's the most similar to HD 176582's?  Let me know if you need help thinking about or calculating this quantity for your star. 

OK, those are quite a few comments and suggestions.  I'd recommend you implement them within the next week, and then we can do another round of comments and revision. 

Thanks for all your work on this.  I'm looking forward to seeing the next version of the talk (and the first version of the paper).  

David

PS Have you made your travel plans for the KNAC meeting?