WB Chapter 1 - Galaxies Step3 Location2

Step3:
For each of the different types of galaxies we go through and determine if the Solar System is within a cluster and of which type it is.


Irregulars are just that "irregular", they follow no set rules and just have a multitude of different objects anywhere they just have to be clustered together. As these are fairly young galaxies and only contain Population I Stars they do not have Globular clusters.

Roll 1d10

1-4 - Your Solar System is in an Open Cluster.

5-10 - Your Solar System is in no particular group and roams free where the buffalo are.

Ellipticals contain Population II stars and contain Globular Clusters rather than the Open kind.

Roll 1d10

1-3 - Your Solar System is in a Globular Cluster.

4-10 - Your Solar System roams free.

If your Solar System is not of any Galaxy then it may have been ejected from a galaxy as part of a group or cluster

Roll 1d10

1-3 - Your Solar System is in a Globular Cluster.

4-6 - Your Solar System is in an Open Cluster.

7-10 - Your Solar System roams free.

Finally we have Spiral Galaxies which are way more complicated. The Bulge is mostly Globular Clusters with some Open Clusters(although uncommon), the Disk is about the opposite with more Open Clusters than Globular Clusters and finally the Galactic Halo has lost all remnants of Stellar Formation and contains only Globular Clusters.

Unfortunately it gets worse, the bulge size has to be taken into account with a smaller bulge you will get younger Population I Stars which means that Open Clusters can be more common than their counterpart, see the list next see the ratios for the different Spiral classes.

• Sa and SBa 70% Globular, 30% Open
• Sb and SBb 50% Globular, 50% Open
• Sc and SBc 15% Globular, 75% Open

So let us first Start with the bulge, I am just going to take a wild guess that around half of all stars have some sort of association with the others around them. so for Sa and Sba classes it would be 40% Globular, 10% Open and 50% None.

Sa and SBa

Roll 1d100

1-40 - Your Solar System is in a Globular Cluster

41-50 - Your Solar System is in an Open Cluster.

51-100 - Your Solar System roams free.

Sb and SBb

Roll 1d100

1-25 - Your Solar System is in a Globular Cluster

26-50 - Your Solar System is in an Open Cluster.

51-100 - Your Solar System roams free.

Sc and SBc

Roll 1d100

1-10 - Your Solar System is in a Globular Cluster

11-50 - Your Solar System is in an Open Cluster.

51-100 - Your Solar System roams free.

The same sort of application applies for the groups on the Disk but Globular Clusters are a lot less common.

Roll 1d100

1-5 - Your Solar System is in a Globular Cluster
6-40 - Your Solar System is in an Open Cluster.
41-100 - Your Solar System roams free.

If you ended up in the Galactic Halo then Roll 1d10

1-4 - Your Solar System is in a Globular Cluster

5-10 - Your Solar System roams free.

E.G.My Star is on the disk in my Galaxy so I roll a 44 which means I am a free roamer.

Notes:
Make sure to note that nearby stars in Open Clusters are of similar age and probably formed in a Molecular Cloud also that most are under 2GY and usually only last a few hundred million years. Also note that Globular Clusters are considerably old and usually don't fall under the 10GY age mark.