47766
For more-massive stars , electron degeneracy pressure does not keep the iron core from collapsing to very great density , leading to formation of a neutron star , black hole , or , speculatively , a quark star .
 neutron star, quark star
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 neutron star, quark star