WB Chapter 1 - Stars Step1 Classification

In the Classification of a star it all depends on the magnitude of the star and from there they begin to determine other attributes of the star using known structures of nearby stars where it is easier to determine such. In this guide we do not have that option, so as we may begin with magnitude the way it is normally done. That would bring us on many different roads where the answers may not always be correct and there would be much work needed to accomplish this, so instead of a random magnitude where it is hard to determine the rarity of a star I will begin with the outright classification of the star.

The simple O,B,A,F,G,K,M, 0-9 and Ia,Ib,II,III,IV,V,VI and with a few more additions.

To begin roll a 1d100

1-12 - Go on to roll a star from Group 1

13-34 - Your star is from Group 2 but being the only type in the group give it a first classification of F


35-72 - Go on to roll a star from Group 3

73-100 - Go on to roll a star from Group 4

To determine whether a Solar System has more than one star make a roll of 3d10. If your solar system is located within an Open Cluster add a modifier of 5 to the roll, if it is in a Globular Cluster add a modifier of 8.
On a roll higher than 15 for the first star add a binary star. For any further star rolls it must be higher than 21.

Keep on rolling until you are satisfied or your roll fails

E.G. on my opening roll I got a 26(Not in a cluster so no modification) so I have a binary star. on my next roll I got a 9 so there are no further rolls. I now name my stars as Sykarr A for the primary star and Sykarr B for the binary star.


Next we need to determine the type of a star in a multiple star system in relation to the to the preceding star.

Roll a 1d10

1-2 - Second star is of identical spectral type and luminosity class, though possibly of another higher numeric  
         specification. Roll 1d10-1 - if lower than the original star, use the original star's number, otherwise use  
         the rolled number.


3+ - Second star is of random type, go back and determine a new group, make sure to keep to the rules 
        explained here because the primary star is always the more massive in classification. However, treat any 
        result that would give a second star of a higher type than the original star as a Brown Dwarf result.

Group1 - 1d10

1-2 - Your star is of type O
2-3 - Your star is of type B

4-6 - Your star is of type A

7-10 - Your star is of type NS - NS Stands for Neutron Star


Group 2


Group 3 - 1d100

1-27 - Your star is of type G

28-59 - Your star is of type K

 60-100 - Your star is of type M

Group 4 - 1d10

1-4 - Your star is of type WD - WD Stands for White Dwarf
5-10 - Your star is of type BD - BD Stands for Brown Dwarf - If you rolled on this type for your primary then ignore it a brown dwarf is extremely unlikely to be a primary star.


E.G. I rolled a 45 so my star is from Group 3. I roll a 96 so my star is of type M


Next we roll a 1d10-1 to determine it's position towards the next type.

E.G. I rolled a 4-1 so 3. My star is now of type M3


The last classifying scheme is to determine the star apart from others of the same type but with a different luminosity class

Roll a 1d100

Note - any star which is of the type BD or NS does not have this luminosity class, so just ignore it. A star of type WD will always be VII in luminosity class

1-2 - The stars Luminosity classification is Ia
3-4 - The stars Luminosity classification is Ib
5-9 - The stars Luminosity classification is II
10-21 - The stars Luminosity classification is III
22-39 - The stars Luminosity classification is IV
40-90 - The stars Luminosity classification is V
91-100 - The stars Luminosity classification is VI


E.G. I rolled a 88 so my primary star is now fully classified as a M3V type star. Because I have 2 stars in my system I had to go back and do the classification steps for the second star. I rolled a 7 so my component B star will be of a different spectral type. Because my original star if from group 3 i must roll a group 3 or 4 star or it will be a Brown Dwarf. I rolled a 15 so my second star is a Brown Dwarf (BD).