Question about globulars

[danny (Daniel)]

Hi ya all,
Had a wander through the wonderious star fields of Sco and Sag last night finding globular clusters. A question came to mind, are globular clusters in a way mini galaxies? From my readings I beleive they are formed before the disk of our galaxy and are made up of very old stars. Are these clusters left over material that didn't make it as part of core of the galaxy, as they are distributed in the spherical halo around the Milky Way, and if they are so old why are there no colour varients in the stars eg (old big red ones.)? Have any nova been found in globulars? Sorry if this sounds abit out there but I was just pondering.

[Dennis]

Hi Danny

Have a look at http://www.seds.org/messier/glob.html for a bit of a read up on these wonderful objects. They can explain it better than I can, and probably more accurately too!

Cheers

Dennis

[danny (Daniel)]

Thanks Dennis, great wealth of info.

[xelasnave]

Danny
I think your observation that globulars are sort of mini gallaxies has some truth in so far as there is support for the proposition that they are the remains of different small gallaxies that has had their outer stars stripped when meeting the larger gallaxy.
I can not give you a link to support the proposition but it sounds reasonable given the way they present, the ages of the stars within and their orbits around the "big" gallaxy.
Which raises the question "Is there a globular associated with the recently discovered remnants of the dwarf gallaxy found in Sagitarius"? I had not thought about it until now but if the above has any merit one would expect to find one I guess. Now there is a search project for all to engage in.
alex

[Doug]

G'day Danny, there is some colour in Globs, but not a lot of variety.
The seds article mentions RR lyre type variables and these can be seen in an animation of M3 at:
http://cfa-www.harvard.edu/~jhartman/M3_movies.html
takes a little time to load because of the 2 animations however I think it could be worth the look.
Cheers,
Doug

[Astroman (Andrew Wall)]

Those animations are way cool, maybe something in that for ome of our DSO imagers to try

[Starkler (Geoff)]

I have seen mention of globulars attached to galaxies other than our own.
Are any of these able to be seen visually?

[robagar]

Maybe around the Andromeda galaxy?

[Doug]

Geof, look here at this site:
http://antwrp.gsfc.nasa.gov/apod/ap021229.html

It is supposed to be about mag 9.7
cheers,
Doug

[ausastronomer (John Bambury)]

Geoff,

The Messier globulars and the vast majority of NGC globulars are contained within our own galaxy and are known as intergallactic globulars. Globulars in other galaxies are known as Extra Galactic Globulars. There are lots of those. The ACS Virgo Cluster Survey categorised 20,000 globular clusters contained within 100 galaxies in the Virgo galaxy group. There are lots that can be seen in larger amateur scopes including those in M31 and M87. Of course there are a multitude of extra galactic globulars to be observed in the LMC and the SMC and a lot of these are visible in smaller amateur scopes.

CS-John B