31038
The central source consists of a low-mass O-type star and a white dwarf , with masses of and respectively .
 O-type star, white dwarf
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:
 O-type star, white dwarf