Assertion: nebula's structure | /r/HasProperty | gas
Facets:
value: around a central object
type: LOCATION
Source sentences:
text: Hubble's crisp images revealed a doughnut-shaped structure composed of dust and gas around a central object, presumably a black hole.
text: These smaller structures, composed of gas and young stars, may be the building blocks from which the more familiar spiral and elliptical galaxies formed, possibly through processes such as multiple galaxy collisions.