Re: [APML] OT: A Deep M13

["Robert Gendler" <robgendler@worldnet.att.net>]

Ray,
Thanks for the education! Knowledge of the science behind the images
really enriches the experience. I didn't know that Globulars as a group
are so complex and dynamic. I will need to speak to Jim Misti as its
his data so I'll get back to you.
Rob Gendler
email: robgendler@att.net
Web Site: http://www.robgendlerastropics.com
----- Original Message ----- 
From: "Ray Butler" <ray.butler@nuigalway.ie>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Monday, April 25, 2005 7:55 AM
Subject: Re: [APML] OT: A Deep M13


>
> Hi Robert,
>
> In my rush to talk about clusters, I forgot to add my compliments on the
> wonderful image! I wonder if it is approaching useful scientific
> quality. Why don't you send me the combined images for each filter band,
> and I'll rustle up some colour-magnitude diagrams? Just for comparison
> with published ones - I bet we'd all be surprised at what can be done
> with such "amateur" data. Has anyone done this before?
>
> Ray "there's a whole lot of astrophysics in those pretty pixels" Butler
>
> >Hi all,
> >Here's an M13 collaboration, data by Jim Misti, processed by me.
> >
> >http://www.robgendlerastropics.com/M13JM.html
> >
> >Just a little clarification about the presence of blue stars in many
> >globulars. Many of us have erroneously attributed the blue population
> >stars to "Blue Stragglers" which have received lots of publicity
recently.
> >Probably the vast majority of blue stars in globulars are blue horizontal
> >branch stars which having exhausted their hydrogen fuel are now
> >fusing helium to carbon. The other bland colored or white stars are
mostly
> >RR Lyrae stars which surprisingly make up a substantial population of
many
> >globulars. The blue stragglers which are likely the result of either
> >collisions
> >in high density central regions or mass transfer in binary systems are
> >considerably
> >dimmer than the helium burning horizontal branch stars and are mostly
> >located
> >in the central dense core of globulars.
> >
> >In summary many of the blue stars we see in CCD images of
> >globulars are blue horizontal branch helium burning stars and not
> >blue stragglers which are mostly central and less luminoius than the
> >other populations mentioned.
> >
> >I hope that professional astronomers out there will let me know if I got
> >some of this wrong.
> >
> >
> >Rob Gendler
> >email: robgendler@att.net
> >Web Site: http://www.robgendlerastropics.com
> >
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> >
> >
>
>
> -- 
> Dr. Ray Butler
> Lecturer, Physics & Astronomy | Physics Department | Computational
Astrophysics Laboratory
> National University of Ireland - Galway, University Road, Galway, Ireland
| www.nuigalway.ie
> ray.butler-AT-nuigalway.ie | Tel: +353-91-524411 ext 3788  | FAX:
+353-91-750584
>
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