The Sun, in an Open Cluster

I read somewhere that the sun is part of an open cluster. If thats true,
wouldn;t it have to be awefully OLD for an open cluster?

What other stars are in the cluster? How many? How large is it? Any
nebula still left?

thanks

jjb

Jeremiah J. Burton wrote:
I read somewhere that the sun is part of an open cluster. If thats true,
wouldn;t it have to be awefully OLD for an open cluster?

What other stars are in the cluster? How many? How large is it? Any
nebula still left?

More precisely, the Sun was almost certainly formed as part of such a
cluster (based on virtually all young stars we see today coming in clusters
and associations). Open clusters lose their identities over time, for
at least two reasons. First, the more of the remaining gas is blown
away by the most massive cluster members (including their supernovae), the
less mass is left to hold the whole cluster together gravitationally.
On top of that, random encounters with stars and massive interstellar
clouds will strip stars away over time. These are reasons that there
are very few open clusters known to nearly as old as the Sun (M67 and
NGC 188?), and the number increases rapidly for smaller ages. By now,
Sol has lost track of the siblings, although there are a few nearby stars
with similar enough space motions that they might share a common
origin.

Bill Keel

Fellow Iowan Sam Wormley was saying
Several of the stars in the "big dipper"
have similar motions about the galaxy
as our sun.

Seems like I can remember reading long ago that Sirius seemed to be
moving along with this group too.
Marty

Marty wrote:

Fellow Iowan Sam Wormley was saying
Several of the stars in the "big dipper"
have similar motions about the galaxy
as our sun.

Seems like I can remember reading long ago that Sirius seemed to be
moving along with this group too.
Marty


I believe I've read that too. There is some doubt that
any of the stars mentioned in the this thread are the remnants of
the original cluster... mostly because the spectral types imply
big age differences.

In article , Sam Wormley wrote:
"Jeremiah J. Burton" wrote:

I read somewhere that the sun is part of an open cluster. If thats true,
wouldn;t it have to be awefully OLD for an open cluster?

What other stars are in the cluster? How many? How large is it? Any
nebula still left?


Several of the stars in the "big dipper" have similar motions about the
galaxy as our sun.

I remember reading that in, I think, T. W. Webb's Celestial Objects
for Common Telescopes, and mentioned it here last year.
Another poster pointed out that the Big Dipper stars must be
much much younger than the Sun. Given that even the dimmest of the
bright ones, Megrez, is a main-sequence A star with about 20 times
the Sun's luminosity, it sure can't be anything approaching
5 billion years old, so presumably the similar space velocity is only
coincidental.

Are there stars with ages compatible with the Sun's that have
similar space velocities? I'm interested in this too.

Stuart

"
Your answer has NOTHING to do with the question Sammy.

How do you figure? He identified several stars that are candidates for
having
formed in the same cluster as the Sun (inferred from similar motion) and
provided evidence for the age of the Solar System, in reference to the age
an
existing open cluster would be. Seems pretty in line with the original
question
to me.

What are YOU talking about. Your previous response went like this

" Sam-

That's a really peculiar statement. What exactly is it saying? Are you
expressing a range with a different tolerance top and bottom? Are these
simply
values given from two different sources?"

Although you are kinda polite, I am not, but our focus was the same. This
Wormley
guy provided a left field answer or comment. Something he does a lot.

"Jeremiah J. Burton" wrote in message
s.com...
I read somewhere that the sun is part of an open cluster. If thats true,
wouldn;t it have to be awefully OLD for an open cluster?

What other stars are in the cluster? How many? How large is it? Any
nebula still left?


I am amazed no one has mentioned Alpha C - A B and C for starters. At 4.36-
4.5 LYs away, they
sure do qualify. Alpha C A is some 7 Billion years old that again
qualifies. The sun is 5-6 Byrs.

http://www.alphacentauri.org/centauri.html

http://www.solstation.com/stars/alp2cent.jpg

Some more on the neighborhood

On Fri, 21 May 2004 01:42:24 GMT, "Thomas" wrote:

I am amazed no one has mentioned Alpha C - A B and C for starters. At 4.36-
4.5 LYs away, they
sure do qualify. Alpha C A is some 7 Billion years old that again
qualifies. The sun is 5-6 Byrs.

Based only on the system's nearness? It has a very high proper motion which
might argue against formation in the same cluster as the Sun (hint: plot the
proper motion backwards 5 billion years; is the system still close?) Also, if
the stars are a billion years or more older than the Sun, that argues against a
common origin, since star forming regions typically have lifetimes measured in
millions of years, not billions.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Fri, 21 May 2004 01:31:16 GMT, "Thomas" wrote:

What are YOU talking about. Your previous response went like this

" Sam-

That's a really peculiar statement. What exactly is it saying? Are you
expressing a range with a different tolerance top and bottom? Are these
simply
values given from two different sources?"

Although you are kinda polite, I am not, but our focus was the same.

Not even close. I wasn't commenting on anything more than some peculiar,
ambiguous wording, which Sam obviously recognized and was quick to clarify.
There was nothing at all wrong with what he was saying, and it was perfectly
relevant to the original question.


This Wormley guy provided a left field answer or comment. Something he does a lot.

I disagree. He often has useful contributions (although generally a bit terse).
You, on the other hand, appear to have little to contribute here other than
negativism. If you think his answers are in left field, I think that says more
about you than him. But like you said, you're not polite, a fact sure to
seriously dilute anything useful you might have to contribute.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com