If the mass of a star’s iron core exceeds the Chandrasekhar limit (but is less than 3 M Sun ), the core collapses until its density exceeds that of an atomic nucleus, forming a neutron star with a typ...If the mass of a star’s iron core exceeds the Chandrasekhar limit (but is less than 3 M Sun ), the core collapses until its density exceeds that of an atomic nucleus, forming a neutron star with a typical diameter of 20 kilometers. The star that evolved to become SN 1987A began its life as a blue supergiant, evolved to become a red supergiant, and returned to being a blue supergiant at the time it exploded.
Coleman Miller of the University of Maryland maintains this site, which goes from easy to hard as you get into it, but it has lots of good information about corpses of massive stars. Magnetars, Soft G...Coleman Miller of the University of Maryland maintains this site, which goes from easy to hard as you get into it, but it has lots of good information about corpses of massive stars. Magnetars, Soft Gamma Repeaters, and Very Strong Magnetic Fields: http://solomon.as.utexas.edu/magnetar.html. Robert Duncan, one of the originators of the idea of magnetars, assembled this site some years ago.
