RR Lyrae stars

[Michael Koppelman <lolife@bitstream.net>]

Hi.

I'm working on an RR Lyrae star that TASS uncovered. I'm trying to 
learn about RR Lyrae stars in the process. Arne recommended the book 
called "RR Lyrae Stars" by Horace Smith. It is very interesting but I 
have a couple of questions:

1. In terms of deriving the mean magnitude of the star, among other 
methods, they mention "Most recent investigations have defined the mean 
magnitude by integrating the lightcurves in intensity units to derive 
the intensity mean magnitude." Anyone care to shed any light on this? 
I'm comfortable with integration but don't really understand what that 
equation would look like.

2. Is there anyway to determine Fe/H by photometry?

3. What do they mean by the term "statistical parallax"? I assume they 
are using the word parallax in the morphed definition of "determining 
distance" (vs. trigonometric parallax). Does this term basically mean 
determining the distance using the statistical parameters of the star 
such as photometry, reddening, radial velocities, etc?

4. If you look at a paper like this: 
http://www.konkoly.hu/cgi-bin/IBVS?5363

It seems odd to me that:

a) They make a claim as to what M-M is with no justification.
b) All of their M-m are less than 1, yet they say that m is ~ 14m and M 
tends to be less than 1 for RR stars. What the hell are they talking 
about that M-m~0.1? I must not be familiar with the terminology.

5. Oddly enough, even though many RR Lyrae stars have the bump prior to 
the rise to maximum, I have not found anything in Smith that explains 
why. I'm still looking. He does mentioned shockwaves that may be 
present at that time but so far no elaboration.

Thanks!
Michael Koppelman