Stellar classification

[TangentFoxy]

• Primary source
• Not included in current model: Spectral peculiarities
• Not included in current model: Wolf-Rayet stars
• Not included in current model: White dwarf classifications
• There are a few other classification notes not included in the model, which will not be included.
• Not included: Cataclysmic variable star
• Binary and ternary star systems not included.
• Not included: Supernovae of any kind.
• Not included: Heavier elements closer to the center.
• Not included: Population I, II, III stars. III are oldest, and have no or almost no elements higher than H/He. II have some "metals", but are poor. I are newest (and biggest since bigger stars have short lifespans, they can't be older populations (citation needed)) and have the highest concentration of metals.
• Metallicity: X+Y+Z=1.00 where X is H, Y is He, and Z is every other element. Relates to Populations, not included currently.

[TangentFoxy]

References and notes to continue researching from:

• https://www.google.com/#q=occurance+of+different+classes+of+stars
• http://www.enchantedlearning.com/subjects/astronomy/stars/startypes.shtml
• http://www.universetoday.com/24299/types-of-stars/
• https://owlcation.com/stem/Different-Types-of-Stars-in-the-Universe
• http://space.about.com/od/stars/tp/What-Are-The-Different-Types-Of-Stars.htm
• https://www.google.com/#q=how+many+stars+are+red+giants
• https://en.wikipedia.org/wiki/Stellar_evolution
• https://en.wikipedia.org/wiki/Star_count
• https://en.wikipedia.org/wiki/UBV_photometric_system
• https://en.wikipedia.org/wiki/White_dwarf
• https://en.wikipedia.org/wiki/Carbon_star
• https://en.wikipedia.org/wiki/File:Size_of_Kepler_Planet_Candidates.jpg
• https://en.wikipedia.org/wiki/List_of_exoplanets
• https://en.wikipedia.org/wiki/Lists_of_planets
• https://en.wikipedia.org/wiki/File:NASA%27s_Hubble_Reveals_Rogue_Planetary_Orbit_For_Fomalhaut_B.jpg
• https://en.wikipedia.org/wiki/Planetary_habitability
• https://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems
• https://en.wikipedia.org/wiki/Astronomical_naming_conventions#Bayer_designation
• https://en.wikipedia.org/wiki/Astronomical_naming_conventions