Globular Clusters and Open Clusters

[Golan2072]

I'm sorry for my sketchy knowledge of astronomy, but I'd like to ahve some data on Globular and Opne clusters, their stellar densities, stellar characteristics (are they linked to nebulae in some cases as I recall?), and the locations of the closets ones to Sol.

Also, are there any disc-shaped small clusters?

 

[TheEngineer]

Hi !

The general answer: Wikipedia
You will find a pretty list of NGCs, Messier and Melotte objects as well as positional data and links to e.g. the SEDS archive with other tons of data.

Sadly, I do not know a fairly condensed list of near sol clusters.
But Hyades are pretty "near" (44 pc), as well as the Plejades (430 ly), NGC1432/S or Mel 111.

Its a bit collecting work.
But perhaps Mr. Thrash has a list already..

regards,

Mert

 

[Malenfant]

Globular clusters are way out there, most orbit the galaxy so there's none anywhere near Sol.

Open Clusters you're a bit better off with, since they're just stars that are clumped together (usually because they form at the same time and place). Though often Open Clusters tend to be rather young because of that - the stars haven't had time to go their separate ways.

http://en.wikipedia.org/wiki/Open_cluster
http://live.yurisnight.net/messier/open.html
http://live.yurisnight.net/messier/glob.html

 

[Golan2072]

What I'm looking for is a colonizable cluster. the big question is, when taking into account their age, would they form planetary systems or life?

 

[Antony]

Planetary systems probably. We seem to be finding planets all over the place. Life? less likely for "native advanced lifeforms", what we need to do is find an old cluster (are there any still more or less intact?). Anyone know where a list of the estimated ages of open clusters can be found?

 

[TheEngineer]

Planetary system: why not ?
But as Malenfant stated the open clusters are astronomically young and so planetary systems and planets would be young (just a few hundred million years or so), too.
This could mean, that geological activity is high and atmosphere is still "under" construction (and perhaps without something like an ozon layer).

Maybe not a good place for native life (except is spawned by some ancients) but a fairly intresting environment for a colony

Could be a setting for a vulcan planet or even a rain planet.

Just take a look on earths conditions around 4 billion years ago

 

[Golan2072]

Hmmm... So alot of colonies would either be terraformed (think Acheron in Aliens; the first movie had it as a "primordial" world; by the second movie it got terraformed to a level where you could breath the atmosphre, but weather sucks) or have domes and underground tunnels.

And microbial life is interesting - its just that coplex lifeforms are probably going to be brought along with the colonists (and with enough gengineering, the point of "alien" vs "earthlife" becomes quite moot from a game POV).

 

[Antony]

Another thing with young systems is the potential for asteroid bombardment. Planets are likely to be in the proverbial shooting gallery which is not condusive to life surving. Earth is believed to have been lucky to survive the earlier phase of this. If I remember correctly the moon is now theorised as having been created when an object the size of Mars impacted the young Earth.
In this regard having large gas giants like Jupiter is probably a bonus as they will sweep up a lot of this material.

 

[Malenfant]

The 'shooting gallery' phase is really early on in a system's evolution (like, the first 500 million years or so). After that things tend to calm down vrey rapidly. Though of course the point is that some of these systems may not be older than that anyway...

The Hyades for example are about 150 ly away and are only 790 million years old. That's long enough for planets to form around stars that can have them and after the main bombardment phase. But they still won't be habitable places to live...

The Pleiades are only about 80 million years old and so definitely won't have any worlds that are safe to live on.

http://www.seds.org/messier/xtra/ngc/hyades.html
http://www.seds.org/messier/m/m045.html

 

[BillDowns]

This is probably off the topic, but I've been curious about systems like Alpha Centauri A & B plus Proxima so close by. Would'nt that make a hash of those systems?

 

[Antony]

Using First In (as good a system for determining life as anything else) The stars in the Hyades could at best (give a +2 mod for age, and +2 if you managed to generate an "Ocean world") A roll of 12 on 2d6 gives a total of 16 which is Protazoa. This would result in the world being classified as a hostile nitrogen world. This corresponds to the young Earth or present day Titan. Definately not a pleasant place to live (unless of course you are the local kingpin of the protazoa).

There are of course small clusters (associations may be a better description) of stars which are technically not open clusters. They may have been once of course. These stars can be of all sorts of ages.

There may be some information on www.solstation.com that could also aid in your researches.

 

[Malenfant]

Originally posted by BillDowns:
This is probably off the topic, but I've been curious about systems like Alpha Centauri A & B plus Proxima so close by. Would'nt that make a hash of those systems?

Alf Cen A and B aren't too close... they're 23.7 AU apart on average with a closest separation of about 11 AU - there's still room enough for planets around each star (within about three AU) there. Proxima on the other hand is about 13,000 AU from the binary so it's nowhere near them.

http://www.solstation.com/stars/alp-cent3.htm

 

[Malenfant]

Originally posted by Antony:
[QB] Using First In (as good a system for determining life as anything else) The stars in the Hyades could at best (give a +2 mod for age, and +2 if you managed to generate an "Ocean world") A roll of 12 on 2d6 gives a total of 16 which is Protazoa. This would result in the world being classified as a hostile nitrogen world. This corresponds to the young Earth or present day Titan. Definately not a pleasant place to live (unless of course you are the local kingpin of the protazoa).

Yeah, that sounds about right - nothing would be there except for the simplest of micro-organisms (prokaryotes?), and probably only around any hydrothermal vents on an ocean floor. The surface environment would be nasty - even though the system's generally settled down so that planet-sized objects aren't smacking into eachother, there will still be a fairly frequent impacts by small asteroids.

There are of course small clusters (associations may be a better description) of stars which are technically not open clusters. They may have been once of course. These stars can be of all sorts of ages.

If the stars have the same proper motion in the sky and are physically near eachother then chances are high that they had a common origin.

You get things like Castor or Xi Scorpii which are sextuple or quintuple systems (6 or 5 stars) , but those aren't really "Clusters".

 

[aramis]

Originally posted by Malenfant:
</font><blockquote>quote:</font><hr />Originally posted by BillDowns:
This is probably off the topic, but I've been curious about systems like Alpha Centauri A & B plus Proxima so close by. Would'nt that make a hash of those systems?

Alf Cen A and B aren't too close... they're 23.7 AU apart on average with a closest separation of about 11 AU - there's still room enough for planets around each star (within about three AU) there. Proxima on the other hand is about 13,000 AU from the binary so it's nowhere near them.

http://www.solstation.com/stars/alp-cent3.htm </font>[/QUOTE]Interestingly enough, Alpha A/B and Proxima are on the TPF and SIM targeting lists, according to solstation. There is a possibility that Proxima isa binary, or has a superjovian planet, too..

Which raises a question to Mal: If the supposed close-companion to P. C. is a brown dwarf, is that potentially thermally significant to the ecosphere?

 

[Malenfant]

A companion to Proxima, as best as I can see, is VERY uncertain. If it's there then it's apparently orbiting around 0.5 AU from the star.

Even if it existed and was a BD, it wouldn't be warm enough now to warm any satellites around it today (if it could even have any, being that close to the star).

 

[Plankowner]

Employee, back to your original Question...

Either use the Hyades cluster if you want to stay relatively close to Terra (within the Solomani Confederation if using OTU) or just make one up. Clusters can stick around for a billion years (ish). You COULD have some planets with simple life on them and reasonably breathable atmospheres. Once you get more than a sector or so away from Terra, you can pretty much do what you want...

IMTU, I used the Pleiades Cluster as a region that acted like a Rift. There were lots of stars there, but no life, few developed systems and LOTS of debris if you wanted to go there. Most of the Pleiades are still in the planet forming age, so very little is economically useful yet. Sure there are lots of resources around, but it is HELL getting to them and getting out alive. I Red Zoned a LOT of star systems. Made for a good wall on one side of the Sector without really effecting play that much. Sounded cool though and I could always point to a spot in the sky and say "Your characters are THERE".

 

[Malenfant]

Originally posted by Plankowner:
[QB]Either use the Hyades cluster if you want to stay relatively close to Terra (within the Solomani Confederation if using OTU) or just make one up. Clusters can stick around for a billion years (ish). You COULD have some planets with simple life on them and reasonably breathable atmospheres. Once you get more than a sector or so away from Terra, you can pretty much do what you want...

It'd be interesting to try to plot where exactly the nearest clusters and nebulae are in Traveller terms. That said the directions are all wrong in the game anyway, and existing stars are in the wrong places too as a result, so I'm not sure it'd be much use in the OTU. Could be handy for a campaign that used 3d-mapping or 3d-stacked sectors though.

 

[Plankowner]

GENERALLY, the Hyades should be located in the Aldebaran or Canopus Sectors (rimward edge)

The Pleiades are probably located rimward of the Banners sector.

As Malenfant said though since all of the marker stars (like Canopus) are not plotted correctly, it might be tough to make it "accurate", so make it fun!

Is there a list of the nearby Open Clusters by RA, DEC and Distance?

 

[TheEngineer]

Hi !

Guess the list of nearby (Traveller ranges) open clusters is fairly short.
We could collect a couple of those here....

Edit:
Just found this site:
http://www.rssd.esa.int/SA-general/Projects/Hipparcos/hyades.html

Contains a nice figure about hyades galactic x/y/z location.

As you can see Plankowners localisation is pretty good. Hyades center seems to be 40 pc rimward of sol (so around hex 1827 in the Aldebaran sector)and a couple of pc below the galactic plane.

Regards,

Mert

 

[TheEngineer]

Hi !

I found something and added a bit...

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">

Namen l b dia dist Stars Vm Remarks
ly
NGC 188 122°8 + 22°5 14' 5000 120 11,5 5 billion years o
Stock 2 133.4 - 1.9 60 8
NGC 869 = h Per 134.6 - 3.7 30 7100 6,5 5,6 million years
NGC 884 = chi Per 135.1 - 3.6 30 7400 8,5 3,2 million years
Tr2 137.4 - 3.9 20 8
NGC 1039 = M34 143.6 - 15.6 35 1400 8
Mel 20 = 147.0 - 7.1 185 3
Plejaden = M45 166.6 - 23.5 110 380 3
Hyaden 180.1 - 22.4 330 120 400 3,5 600 million years
NGC 1647 180.4 - 16.8 45 8,5
NGC 1778 168.9 - 2.0 7 9
NGC 1912 = M38 172.3 + 0.9 21 4200 9 220 million years
NGC 1960 = M36 174.5 + 1.0 12 4100 60 9 25 Million years
NGC 2099 = M37 177.7 + 3.1 24 4400 500 10,5 300 Million years
NGC 2158 186.6 + 1.8 5 2800 11 1 billion years
NGC 2168 = M35 186.6 + 2.2 28 2800 450 8 100 million years
NGC 2169 195.6 - 2.3 7 3600 30 7
NGC 2244 206.4 - 2.0 24 5500 6,5 130 ly diameter
NGC 2264 202.9 + 2.2 20 2400 7,5 star breeder
NGC 2287 = M41 231.1 - 10.2 38 2300 100 6 190 million years
Cr 121 235.4 - 10.4 50 6
NGC 2323 = M50 221.7 - 1.3 16 3200 200 8 10 ly diameter
NGC 2360 229.8 - 1.4 13 6150 9
NGC 2362 238.2 - 5.5 8 5000 60 7 25 million years
Cr 140 245.2 - 7.9 42 5,5
NGC 2420 198.1 + 19.6 10 11
NGC 2451 252.4 - 6.7 45 850 40 4 36 million years
NGC 2477 253.6 - 5.8 27 4200 300 10 700 million years
NGC 2533 247.8 + 1.3 4 9
NGC 2547 264.6 - 8.6 20 1960 6,5
NGC 2546 254.9 - 2.0 41 3300 6,5
NGC 2632 = Praesepe 205.5 + 32.5 95 577 350 6,5 790 million years
NGC 2682 = M67 215.6 + 31.7 30 2700 500 10 5 billion years o
NGC 3114 283.3 - 3.8 35 6
IC 2581 284.6 + 0.0 8 7
IC 2602 289.6 - 4.9 50 479 3
NGC 3532 289.6 + 1.5 55 1300 7,5
NGC 3766 294.1 + 0.1 12 5500 8
IC 2944 294.6 - 1.4 15 6,5
NGC 4349 299.8 + 0.8 16 8,5
Mel 111 = Coma 221.1 + 84.1 275 5
NGC 4755 303.2 + 2.5 10 7600 7 7,1 million years
Cr 285 = UMa Haufen 110.3 + 44.9 2
NGC 6067 329.8 - 2.2 13 8,5
NGC 6087 327.8 - 5.4 12 7,5
NGC 6231 343.5 + 1.2 15 5900 6,5 3,2 million years
NGC 6405 = M6 356.6 - 0.7 15 1600 7 Butterly cluster,
IC 4665 + 17.1 41 1400 30 7 36 million years
NGC 6475 = M7 355.9 - 4.5 80 800 80 6 220 million years
NGC 6530 - 1.1 15 5200 100 6 2 million years
IC4725 = M25 - 4.5 32 2000 8 89 million years
NGC 6705 = M11 - 2.8 14 6000 2900 10,5 250 million years
NGC 6791 70.0 + 10.9 16 13,5
NGC 6939 95.9 + 12.3 8 10
NGC 7063 83.1 - 9.9 8 9
NGC 7092 = M39 92.5 - 2.3 32 800 100 6,5 250 million years
TR 37 = IC 1396 99.3 + 3.7 50 7
NGC 7160 104.0 + 6.5 7 8
NGC 7209 95.5 - 7.3 25 10
NGC 7380 107.1 - 0.9 12 7200 8,5
NGC 7789 116.6 + 1.0 16 7600 10</pre>[/QUOTE]I will try to calc some x/y/z coordinates ...

regards,

Mert