Assertion: nebula's star | /r/ObjectUse | used up all the hydrogen
Facets:
value: at its core
type: LOCATION
Source sentences:
text: It was created roughly 10,000 years ago, when a Sun-like star used up all the hydrogen at its core, started to cool and expand, growing by tens to hundreds of times its original size, and eventually expelled its outer layers to form the planetary nebula.