mõõduka massiga tähtede plahvatuse järel nendest eemalduv ja kerakujuliselt paisuv jäänukudu
nebula consisting of an expanding, glowing shell of ionized gas ejected from old red giant stars late in their lives
Hea teada
The word "nebula" is Latin for mist or cloud, and the term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. Reference: 'Planetary nebula'. Wikipedia, https://en.wikipedia.org/wiki/Planetary_nebula [18.5.2017]
A planetary nebula is a region of cosmic gas and dust formed from the cast-off outer layers of a dying star. Despite their name, planetary nebulae have nothing to do with planets.
