Assertion: nebula | /r/LocatedNear | the star
Facets:
Source sentences:
text: A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star
text: In 1912, American astronomer Vesto Slipher added the subcategory of Reflection Nebulae after observing how a nebula surrounding a star matched the spectra of the Pleiades open cluster.
text: A third category was added in 1912 when Vesto Slipher showed that the spectrum of the nebula that surrounded the star