Models that I created for my Earth & Space science class.  
I printed in 0.2 mm layer heights with 10% infill.
 

The Star Core Collapse has arrows with the inward crush of gravity on the layered core.
 

The Core slice shows a cutaway zoomed in with all of the “burning shells” of elements; hydrogen, helium, carbon, neon, oxygen, silicon, and the degenerate iron core.
 

There is also a Whole Core model that names each element.
 Both the whole core and core slice models are 7.6 mm tall and can be printed at the same time to cut down on the 12 filament changes.   Each of the element symbols / names is 0.2 mm tall, except for Fe / iron which is 2 additional layers higher so the white on black stands out better. 

I printed the Star Core Collapse model in blue as it ties in to my Hertzsprung-Russel Diagram model color scheme for the most massive O type stars.
https://www.printables.com/model/1113103-hertzsprung-russell-diagram

I also use the same element color scheme for my Elemental Abundance of the Universe model
https://www.printables.com/model/1120262-elemental-abundance-in-the-universe-model