Here's a short (12 page) and pretty easy article from The Astrophysical Journal (2003), about end of life for massive stars. And why some would "directly" collapse (no big & bright supernova) into black holes.<p><a href="https://open.clemson.edu/cgi/viewcontent.cgi?article=1006&context=physastro_pubs" rel="nofollow">https://open.clemson.edu/cgi/viewcontent.cgi?article=1006&co...</a>