CONTRARY TO EXPECTATIONS FROM CURRENT STELLAR EVOLUTIONARY MODELS RECENT OBSERVATIONS UNCOVERED THE EJECTION OF SHELLS OF MATERIAL BY MASSIVE STARS IN THE YEARS BEFORE THE SUPERNOVA (SN) EXPLOSION. THE PHYSICAL MECHANISM BEHIND THE IMPULSIVE MASS EJ
$0FY2021National Aeronautics and Space AdministrationNASA
Northwestern University, Evanston IL