ASTRO: NGC 7419

NGC 7419 is the richest known coeval (all stars are the same age)
cluster of red super giants in the galaxy. It doesn't take many for
this distinction as it has only 5. Most clusters of this type have a
ratio of blue super giants to red ones of almost 2:1. This cluster the
ratio is 0.2:1, that is it has only one. That one is questionable so it
may contain none. And no that star is not at all obvious, in fact it is
very red! Why I can only guess, though the entire cluster is obviously
severely reddened by dust. Apparently little of its blue light is
getting through the dust. In fact none its blue stars shines with a
blue color. The best they can do is a slightly reddish white in my
image. The blue stars you see are foreground stars it would appear.
http://iopscience.iop.org/1538-3881/...126_3_1415.pdf

One paper puts the reddening at 1.65 magnitudes and gives a distance of
9500 ± 1300 light-years. The reddening varies quite a bit across the
cluster but on average the dust dims the cluster by 5.1 ± 0.4 That
doesn't seem enough to explain why its hottest and bluest star is so
red. It is red on the POSS plates as well. Many of its blue B stars
are Be stars meaning they have emission lines. The age of the cluster
appears to be about 25 million years but the Be stars are far younger,
0.3 to 3 million years old. So the cluster may have had two periods of
star formation. The article also indicates the dust from this formation
is still reddening the cluster. The super giant blue star is not one of
these young stars however.
http://arxiv.org/PS_cache/astro-ph/p.../0605017v2.pdf

In the annotated image the red super giants are denoted by R, (MY Cephi
is the one furthest to the NE--upper left) the possible single blue
super giant by BSG? (it is certainly not a Be star) and three young blue
emission line stars by Be. One of those is also questionable so I've
added a question mark for it. B denotes ordinary blue giant stars.
There is one carbon star, MZ Cephi, in the cluster. It is denoted by C.
It confused me at first as the cluster appeared to have 6 red super
giants until I saw one was a bright carbon star instead. G denotes a
background galaxy that looks much like a star that's a member of the
cluster. It is 2MASX J22541342+6048221. NED has no distance or even
magnitude estimate for it. There are a couple other galaxies in the
image as well. They too look like faint stars. They are labeled in the
annotated image with a G.

I've included both a full size (1" per pixel) and reduced (1.5" per
pixel) image. In the past when I posted just the reduced image I get
emails asking for the full one. Reduced fits today's monitors better
with no real loss of resolution when the image is of just stars. So I'm
including both as a time saver for me. Which size do you prefer?

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Rick
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Correct domain name is arvig and it is net not com. Prefix is correct.
Third character is a zero rather than a capital "Oh".