▁to ▁form ▁neut rons ▁by ▁means ▁of ▁electron ▁capture , ▁an ▁electron ▁neut r ino ▁is ▁produced . ▁In ▁a ▁typical ▁Type   II ▁super n ova , ▁the ▁newly ▁formed ▁neut ron ▁core ▁has ▁an ▁initial ▁temperature ▁of ▁about ▁ 1 0 0 ▁billion ▁k el v ins , ▁ 1 0 4 ▁times ▁the ▁temperature ▁of ▁the ▁Sun ' s ▁core . ▁Much ▁of ▁this ▁thermal ▁energy ▁must ▁be ▁shed ▁for ▁a ▁stable ▁neut ron ▁star ▁to ▁form , ▁otherwise ▁the ▁neut rons ▁would ▁" bo il ▁away ". ▁This ▁is ▁accomplished ▁by ▁a ▁further ▁release ▁of ▁neut r inos . ▁These ▁' ther mal ' ▁neut r inos ▁form ▁as ▁neut r ino - antine ut r ino ▁pairs ▁of ▁all ▁flav ors , ▁and ▁total ▁several ▁times ▁the ▁number ▁of ▁electron - capt ure ▁neut r inos . ▁The ▁two ▁neut r ino ▁production ▁mechan isms ▁convert ▁the ▁gravit ational ▁potential ▁energy ▁of ▁the ▁collapse ▁into ▁a ▁ten - second ▁neut r ino ▁burst , ▁re le asing ▁about ▁ 1 0 4 6 ▁jou les ▁( 1 0 0   fo e ). ▁ ▁Through ▁a ▁process ▁that ▁is ▁not ▁clearly ▁understood , ▁about ▁ 1 %, ▁or ▁ 1 0 4 4   jou les ▁( 1   fo e ), ▁of ▁the ▁energy ▁released ▁( in ▁the ▁form ▁of ▁neut r inos ) ▁is ▁re abs or bed ▁by ▁the ▁st alled ▁shock , ▁producing ▁the ▁super n ova ▁explos ion . ▁Ne ut r inos