Comments on: Spectacular and sparkling, but what is it?

By: tracer

tracer — Wed, 25 May 2011 01:47:40 +0000

Hrm … I wonder if a LOT of globular clusters aren’t the remains of galactic cannibalism.

I remember hearing that most elliptical galaxies (which would include dwarf ellipticals) undergo one, and ONLY one, period of star formation when the galaxy first comes together. If THAT kind of galaxy collided with the Milky Way, got stripped of most of its stars, and ended up as a globe-shaped mass, it would be indistinguishable from Globular Clusters that formed the “normal” way.

… unless galactic cannibalism IS the “normal” way.

By: rwhite

rwhite — Tue, 24 May 2011 20:23:59 +0000

Do we have any idea of the general distance between any two stars in the cluster?

By: Grimbold

Grimbold — Mon, 23 May 2011 21:28:30 +0000

@4- I think a merger between two globulars is definitely plausible. That would explain the two different populations of stars. It could also explain the flattened appearance of Terzan 5; mergers between two objects moving relative to each other impart angular momentum to the merged object, making it rotate.

By: chris j.

chris j. — Mon, 23 May 2011 19:57:43 +0000

Georg, those stars all appear to be the same age.

By: Whomever1

Whomever1 — Mon, 23 May 2011 18:47:42 +0000

So, globular cluster or dwarf galaxy remnant–would there be a black hole in the center of it?

By: Georg

Georg — Mon, 23 May 2011 18:39:28 +0000

This star cluster is made for soups:

http://img.fotocommunity.com/images/Essen-Trinken/Pasta/Sternchen-Nudeln-mal-ganz-gross-a23047253.jpg

By: Matt B.

Matt B. — Mon, 23 May 2011 18:07:34 +0000

The second picture is rotated 90 degrees counterclockwise compared to the first. You can tell by paying attention to a small trapezoid of stars near the center and a pair near that (half-way to the left edge in the second picture).

By: Thea

Thea — Mon, 23 May 2011 18:02:44 +0000

You said the colour contrast between the two groups of stars was more obvious in the Hubble image than in the VLT image. To me, however, the colour difference is more obvious in the VLT picture. I suppose it’s different to different people.

By: HvP

HvP — Mon, 23 May 2011 17:57:44 +0000

I guess I’ve been so used to the older Messier and Herschel catalogs, and the names assigned from orbiting platforms, that the prefix “Terzan” sounds very odd.

No disrespect to Mr. Agop Terzan, but the designation Terzan 5 sounds like something a Star Trek writer would have come up with. Actually, that’s pretty cool. Who wouldn’t want to have something this interesting named after them? And to be able to give it such a cool name at that

By: chris j.

chris j. — Mon, 23 May 2011 17:14:43 +0000

if terzan 5 is a galactic remnant with sufficient gravity to avoid being stripped by the milky way entirely, then shouldn’t there be streamers like the canis major dwarf or sag deg?

Messier Tidy Upper @5:
i’ve often read how the stars within a single globular tend to be the same age, but i’ve never thought to ask before: are all of the milky way’s globulars the same age?

By: STANLEY

STANLEY — Mon, 23 May 2011 16:00:58 +0000

It’s almost like I want to feel that region of distorted space-time in which that cluster is located!

By: Michael Sternberg

Michael Sternberg — Mon, 23 May 2011 15:37:18 +0000

Chris: Not sure how isophotes are usually done, but if I apply a Gaussian Blur (r = 50) and then a posterization (n = 10 … 15 levels, say), the cluster comes out only slightly egg-shaped, thick end on the left, thin on the right.

By: Messier Tidy Upper

Messier Tidy Upper — Mon, 23 May 2011 15:25:37 +0000

Wonderful image. Superluminous! (Beyond mere brilliance)

Seems a bit like Omega Centauri which is similarly suspected of being a former dwarf galaxy in its own right. (Edit : As #3 Chris A has noted already I see.)

Oh & because someone here has to say it :

“My God its’ full of stars!”
-Dave Bowman, ‘Space Odyssey : 2001′, Arthur C. Clarke & Stanley Kubrick

@4. dave cortesi : I think the idea is that all the Milky Way’s globular clusters formed at much the same time all at once and should therefore have stellar populations of stars that are all about the same age which clashes with the varying ages of the stars in Terzan 5.

By: dave cortesi

dave cortesi — Mon, 23 May 2011 15:21:30 +0000

What’s wrong with it being a merger between two globulars? They must occasionally interact, mustn’t they? Which would account for two age-cohorts in one cluster.

By: Chris A.

Chris A. — Mon, 23 May 2011 14:38:22 +0000

Just looking at it, I’d wager that its isophotes are nowhere close to circular, compared to your average globular. It looks distinctly flattened at the top, unless that’s more of the non-uniform extinction.

Also, haven’t they identified at least three epochs of star formation in Omega Cen? Perhaps the paradigm of globular cluster star formation occurring in one go is beginning to fall apart.

By: Michael Sternberg

Michael Sternberg — Mon, 23 May 2011 14:33:04 +0000

I have a hard time matching the two images. Are they meant to be similar in field of view and orientation? They are both optical (or nearly so), so we’d expect roughly similar stellar magnitudes, right?

Always wondered – do astronomers develop an intuition for connecting dots?

By: Melissa

Melissa — Mon, 23 May 2011 13:34:40 +0000

Looks like star soup. Mmmm…star soup.