Assertion: nebula's region | /r/HasProperty | conspicuous ionized
Facets:
Source sentences:
text: The Orion Nebula, for example, is merely a conspicuous ionized region on the nearby face of a much larger dark cloud; the H II region is almost entirely produced by the ionization provided by a single hot star, one of the four bright central stars (the Trapezium) identified by Dutch astronomer Christiaan Huygens in 1656.