I have used the default game resources and expanded on them to increase the diversity of the star types during map generation.  Specifically it adds:

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As of version 1.3

- 23 star types grouped by classes:

     - 1 Class O star
     - 3 Class B stars
     - 3 Class A stars
     - 3 Class F stars
     - 3 Class G stars
     - 4 Class K stars
     - 6 Class M stars

- 55 star system types during map generation, including binary and trinary stars

- a custom made star name list based on the Bayer nomenclature

- a reduction of the frequency of star/planet/black holes/asteroid depending on map size