This beautiful tuesday morning, Dave tutors us on relaxation and cluster core collapse.
Then it is party at Alison's place.
But, first, we go through thermodynamics of self-gravitating internally relaxed systems, multiple equilibria and general dimensionless solutions.
Open Cluster M7 (from Utahskies.org)
Globular cluster M4 (from Utahskies.org)
Core collapsed? Or not?
Globular cluster M15 (from Utahskies.org - ok actually hubblesite, but they had a scaled copy and I was on a roll)
Definitely core collapse, we think.
Seriously - there are more core collapsed or post-core collapsed clusters in the inner parts of the galaxy, as there should be, we think, maybe, depending on your definition.
M15 really almost certainly is in post-core collapse bounce, it is the only sensible way to explain PSR M15C and many other things about it.
But M4?
Which is it? A nice pre-collapse King model cluster?
Or a strongly modified way past post-core collapse cluster...?
ω Cen - absolutely positively definitely NOT a globular cluster
ω Cen is a nuisance, it violates all precepts about globulars, except how it looks,
ergo, it is not a globular
right?
"except how it looks, ergo, it is not a globular right?"
If it looks like a spherical cow, and moos like a spherical cow, it probably is a spherical cow.
Except that Omega Cen is not, alas, spherical...