Assertion: nebula | /r/HasProperty | material
Facets:
Source sentences:
text: The nebula is composed of material cast off by a dying sun-like star as it enters its white dwarf phase of evolution.
text: Messier 1 is also classified as a pulsar wind nebula, which means that the nebula is made of the material ejected by a pulsating neutron star interacting with interstellar gas and the magnetic field of the pulsar itself.