Assertion: nebula's star | /r/HasProperty | planetary nebulae
Facets:
Source sentences:
text: Roughly one-third of them had the emission spectrum of a gas (i.e. Emission Nebulae) while the rest showed a continuous spectrum, consistent with a mass of stars (i.e. Planetary Nebulae).
text: NASA's Hubble Space Telescope has shown us that the shrouds of gas surrounding dying, sunlike stars (called planetary nebulae) come in a variety of strange shapes, from an "hourglass" to a "butterfly" to a "stingray.