Re: GSC 540-84

[Michael Koppelman <lolife@bitstream.net>]

Hmm. I'll have to get used to your new terminology. I'm guessing that  
this star is what you describe as an RR0 type star, in that, according  
to Arne at least, it looks like there are not overtones, only the  
Blazhko effect. If I'm interpreting the new terminology correctly and  
understanding some of your conclusions correctly, it seems that the  
Blazhko effect is indeed rarer in stars pulsating in/with an overtone,  
which the RRc generally are.

Part of my confusion is: it seems to me that it could be hard to tell  
whether something is modulating in period or amplitude. If the primary  
period is much stronger, either case is going to look like a periodic  
alteration of the primary period. Am I correct that the Blazhko effect  
is an amplitude modulation and that the overtones you discuss are  
modulations in the period? I'm a musician so it's easy for me to view a  
complex wave as the sum of a primary "note" and overtones. The Blazhko  
effect, although I have more to read, seems to not be the sum of more  
than one "notes" but the actual modification of a single note?

Feel free to reply: "Go read more, Michael!"  ;)

Michael

On Saturday, October 4, 2003, at 05:32 PM, Doug Welch wrote:

> If you want to read the latest on statistics of RRc Blazhko's,
> check out our paper:
>
> "The MACHO Project Large Magellanic Cloud Variable-Star Inventory. IX.
> Frequency Analysis of the First-Overtone RR Lyrae Stars and the  
> Indication
> for Nonradial Pulsations"
> Astrophysical Journal, Volume 542, Issue 1, pp. 257-280
>
> http://adsabs.harvard.edu/cgi-bin/nph- 
> bib_query?bibcode=2000ApJ...542..257A&db_key=AST
>
> There is a similar paper for the RRab's currently in press.