Also, four of them are known to have planetary nebulae. -- Joe --- On Sun, 6/14/09, Kim <kimharch@cut.net> wrote: From: Kim <kimharch@cut.net> Subject: Re: [Utah-astronomy] M22's Blue Stars (continued) To: "'Utah Astronomy'" <utah-astronomy@mailman.xmission.com> Date: Sunday, June 14, 2009, 7:35 PM I recall an article some years back in either Astronomy or S&T that discussed one globular cluster in another galaxy that was extremely young compared to virtually all other known globulars. The evidence was a very high number of blue giants. Anyone else recall that article or know anything about this? Are the following facts correct for public star parties? 1. Globular clusters are not well understood. 2. GS are typically very old, on the order of 10 to 13 BY. 3. They are typically only a couple of dozen LY in diameter but with a density of hundreds to thousands of times that of our galactic neighborhood. (Of course "size" depends on to what point one measures the radius, core radius and half-light radius are the most common measures, I think - probably too much to try to explain in a public setting.) 4. GS may contain hundreds of thousands to well over 1 million stars. Anything else I should add? Kim

-----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy- bounces@mailman.xmission.com] On Behalf Of Jay Eads Sent: Sunday, June 14, 2009 6:02 PM To: Utah-Astronomy Subject: Re: [Utah-astronomy] M22's Blue Stars (continued)

I came across this article on Globulars and found the study to be quite interesting. It is located at http://www.astronomynow.com/Oldglobularclusterssurprisinglyyoung.html    and discusses that though the stars in globulars are old, if the study is confirmed, many globulars are either in their adolescence or in middle age in terms of their development.

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