( Pulsars ( ( are ( ( ( neutron stars ) , ) ( ( the ( ( highly dense ) ( , ( collapsed cores ) ) ) ) ( of ( stars ( that ( are ( ( thrown out ) ( in ( ( stellar explosions ) ( called supernovas ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Pulsars)) (VP (VBP are) (NP (NP (NN neutron) (NNS stars)) (, ,) (NP (NP (DT the) (ADJP (RB highly) (JJ dense)) (, ,) (JJ collapsed) (NNS cores)) (PP (IN of) (NP (NP (NNS stars)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (VP (VBN thrown) (PRT (RP out)) (PP (IN in) (NP (NP (JJ stellar) (NNS explosions)) (VP (VBN called) (NP (NNS supernovas)))))))))))))) (. .)))
Pulsars are neutron stars, the highly dense, collapsed cores of stars that are thrown out in stellar explosions called supernovas.
(ROOT (S (NP (NN Neutron) (NNS stars)) (VP (VBP are) (NP (NP (DT the) (NNS corpses)) (PP (IN of) (NP (ADJP (VBN left) (RP over)) (NN supernova) (NNS explosions))))) (. .)))