Re: [Utah-astronomy] M22, Part 2
This makes me wonder if one of my basic assumptions is wrong. I thought all globulars were extremely ancient. But could a population of blue stars be as old as red ones? Can someone help me understand this? Thanks, Joe --- On Thu, 6/11/09, erikhansen@TheBlueZone.net <erikhansen@TheBlueZone.net> wrote: From: erikhansen@TheBlueZone.net <erikhansen@TheBlueZone.net> Subject: Re: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, June 11, 2009, 10:32 AM
It seems it depends on type of stars make up the Globular. I searched briefly and found a Globular with OB associations are likely to be blue and are found in the disk of our galaxy which is the case of M22. Globular Clusters in the halo of our galaxy are likely to be red.
I'm not sure. I've seen it in other photos of globular clusters, too. One
reason may be that in order to show anything other than a big glare, the brightness had to be adjusted. Possibly the bright stars that remained somehow influenced the color balance to make the dimmer ones look blue. If someone else knows, I'd like to hear. Thanks, Joe
--- On Thu, 6/11/09, M Wilson <astro_outwest@yahoo.com> wrote:
From: M Wilson <astro_outwest@yahoo.com> Subject: Re: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, June 11, 2009, 8:49 AM
Great writing and article, Joe. I have a question though. M22 and other globulars are supposed to be populated with old aged red stars, but your photo, and many (but not all) others I've seen on the Internet, indicates that the colors of those stars to be blue. Is there an explanation for this?
--- On Wed, 6/10/09, Joe Bauman <josephmbauman@yahoo.com> wrote:
From: Joe Bauman <josephmbauman@yahoo.com> Subject: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Wednesday, June 10, 2009, 11:31 PM
Hi Friends, Here's the second, and for now, last, part of my M22 epic.
http://www.deseretnews.com/blogs/1,5322,10000034,00.html?bD=20090610
Thanks, Joe
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
Blue stars do not live a long time. The hotter a star, the faster it uses it's fuel. Blue stars are giants and super-giants. Red giants are physically large, but not nearly as massive as blue stars. They are bloated, distended envelopes and represent the last stages of a star's life before core collapse and transformation into a white dwarf or neutron star. If Erik is right and there are two types of globular (disk and halo), then I suspect the amount of gas in each is radically different. Very little gas in older globulars, so no new star formation. On Thu, Jun 11, 2009 at 10:48 AM, Joe Bauman <josephmbauman@yahoo.com>wrote:
This makes me wonder if one of my basic assumptions is wrong. I thought all globulars were extremely ancient. But could a population of blue stars be as old as red ones? Can someone help me understand this? Thanks, Joe
Joe, take a look at this: http://antwrp.gsfc.nasa.gov/apod/globular_clusters.html On Thu, Jun 11, 2009 at 10:48 AM, Joe Bauman <josephmbauman@yahoo.com>wrote:
This makes me wonder if one of my basic assumptions is wrong. I thought all globulars were extremely ancient. But could a population of blue stars be as old as red ones? Can someone help me understand this? Thanks, Joe
Joe, See image of M13 at http://www.redorbit.com/images/gallery/hubble_space_telescope/hubble_acswfpc 2_image_of_globular_cluster_m13/18/40/index.html taken by Hubble. There are still many blue stars but more are older reddish stars. The blue stars, because they are in general more luminous, appear more common than they really are. -----Original Message----- From: utah-astronomy-bounces@mailman.xmission.com [mailto:utah-astronomy-bounces@mailman.xmission.com] On Behalf Of Chuck Hards Sent: Thursday, June 11, 2009 12:30 PM To: Utah Astronomy Subject: Re: [Utah-astronomy] M22, Part 2 Joe, take a look at this: http://antwrp.gsfc.nasa.gov/apod/globular_clusters.html On Thu, Jun 11, 2009 at 10:48 AM, Joe Bauman <josephmbauman@yahoo.com>wrote:
This makes me wonder if one of my basic assumptions is wrong. I thought all globulars were extremely ancient. But could a population of blue stars be as old as red ones? Can someone help me understand this? Thanks, Joe
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
I think what is true is that stars in globular clusters are off the main sequence, which the majority are red giants. So, I think your basic assumption is still correct.
This makes me wonder if one of my basic assumptions is wrong. I thought
all globulars were extremely ancient. But could a population of blue stars be as old as red ones? Can someone help me understand this? Thanks, Joe
--- On Thu, 6/11/09, erikhansen@TheBlueZone.net <erikhansen@TheBlueZone.net> wrote:
From: erikhansen@TheBlueZone.net <erikhansen@TheBlueZone.net> Subject: Re: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, June 11, 2009, 10:32 AM
It seems it depends on type of stars make up the Globular. I searched briefly and found a Globular with OB associations are likely to be blue and are found in the disk of our galaxy which is the case of M22. Globular Clusters in the halo of our galaxy are likely to be red.
I'm not sure. I've seen it in other photos of globular clusters, too. One
reason may be that in order to show anything other than a big glare, the brightness had to be adjusted. Possibly the bright stars that remained somehow influenced the color balance to make the dimmer ones look blue. If someone else knows, I'd like to hear. Thanks, Joe
--- On Thu, 6/11/09, M Wilson <astro_outwest@yahoo.com> wrote:
From: M Wilson <astro_outwest@yahoo.com> Subject: Re: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Thursday, June 11, 2009, 8:49 AM
Great writing and article, Joe. I have a question though. M22 and other globulars are supposed to be populated with old aged red stars, but your photo, and many (but not all) others I've seen on the Internet, indicates that the colors of those stars to be blue. Is there an explanation for this?
--- On Wed, 6/10/09, Joe Bauman <josephmbauman@yahoo.com> wrote:
From: Joe Bauman <josephmbauman@yahoo.com> Subject: [Utah-astronomy] M22, Part 2 To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Date: Wednesday, June 10, 2009, 11:31 PM
Hi Friends, Here's the second, and for now, last, part of my M22 epic.
http://www.deseretnews.com/blogs/1,5322,10000034,00.html?bD=20090610
Thanks, Joe
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
_______________________________________________ Utah-Astronomy mailing list Utah-Astronomy@mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy Visit the Photo Gallery: http://www.slas.us/gallery2/main.php Visit the Wiki: http://www.utahastronomy.com
participants (4)
-
Chuck Hards -
Don J. Colton -
erikhansen＠TheBlueZone.net -
Joe Bauman