Assertion: supernova's progenitor star | /r/CapableOf | experience periodic nova eruptions
Facets:
value: before the supernova
type: TEMPORAL
Source sentences:
text: Ia. Direct observations of the progenitor of PTF 11kx were reported in the August 24 edition of Science and support this conclusion, and also show that the progenitor star experienced periodic nova eruptions before the supernova – another surprising discovery.