by Ann » Wed Nov 15, 2017 7:24 am
Of course the apparent dominance of red giants in a cluster is clearly dependent on the overall color balance of the picture. Take a look at two pictures of old open cluster
M67, which is at least twice as old as Caroline's Cluster, and which may be as old as the Sun:
M67, blue (or saturated) color balance.
Palomar Observatory / STScI / WikiSky.
And check out
this page for a huge number of great pictures of and facts about M67!
By the way, check out the Wikipedia entry about M67, where it says:
Wikipedia wrote:
Richer et al.[7] estimate its age to be 4 billion years, its mass to be 1080 solar masses, and the number of white dwarfs to be 150. Hurley et al.[8] estimate its current mass to be 1400 solar masses and
its initial mass to be approximately 10 times as great.
Yes, open clusters do lose mass over time, don't they? They have to be born very massive to survive for more than a billion years, let alone for 3-5 billion years.
I also recommend
this post, made by me, when Caroline's Cluster got another APOD.
In that APOD, NGC 7789 looked bluer than it does in today's APOD.
Ann
Of course the apparent dominance of red giants in a cluster is clearly dependent on the overall color balance of the picture. Take a look at two pictures of old open cluster [url=https://en.wikipedia.org/wiki/Messier_67]M67[/url], which is at least twice as old as Caroline's Cluster, and which may be as old as the Sun:
[float=left][img2]http://cs.astronomy.com/resized-image.ashx/__size/1000x0/__key/telligent-evolution-components-attachments/13-60-00-00-00-46-44-51/NGC2682ASTR.jpg[/img2][c][size=85]M67, red (or yellow) non-saturated color balance.
Source: http://cs.astronomy.com/asy/m/starclusters/464451.aspx[/size][/c][/float] [float=right][img2]http://scienceblogs.com/startswithabang/files/2013/01/messier-67.jpeg[/img2][c][size=85]M67, blue (or saturated) color balance.
Palomar Observatory / STScI / WikiSky.[/size][/c][/float]
And check out [url=http://scienceblogs.com/startswithabang/2013/01/14/messier-monday-messiers-oldest-open-cluster-m67/]this page[/url] for a huge number of great pictures of and facts about M67!
By the way, check out the Wikipedia entry about M67, where it says:
[quote][url=https://en.wikipedia.org/wiki/Messier_67]Wikipedia[/url] wrote:
Richer et al.[7] estimate its age to be 4 billion years, its mass to be 1080 solar masses, and the number of white dwarfs to be 150. Hurley et al.[8] estimate its current mass to be 1400 solar masses and [size=110][i][b][color=#FF00FF]its initial mass to be approximately 10 times as great[/color][/b][/i][/size].[/quote]
Yes, open clusters do lose mass over time, don't they? They have to be born very massive to survive for more than a billion years, let alone for 3-5 billion years.
I also recommend [url=http://asterisk.apod.com/viewtopic.php?p=212128#p212128]this post[/url], made by me, when Caroline's Cluster got another APOD. [url=https://apod.nasa.gov/apod/ap131026.html]In that APOD[/url], NGC 7789 looked bluer than it does in today's APOD.
Ann