Some of these objects evolve too slowly to ever become bright enough for observation, which Alvio Renzini dubbed their "lazy" variety.
Some of these objects evolve too slowly to ever become bright enough for observation, which Alvio Renzini dubbed their "lazy" variety. Majaess et al. made a precise calculation of the distance to one of these objects named PHR 1315-1655 by showing that it is part of the open cluster Andrews-Lindsay 1. Microstructures in these objects include supersonic jets with point or major-axis symmetry, respectively called BRETs and (*) FLIERs. These objects exhibit a strong emission line at 500.7 nanometers due to a forbidden transition of doubly ionized oxygen. For a Sun-like star, the evolutionary stage named for these objects has a duration on the order of tens of thousands of years and occurs in between the asymptotic giant branch and white dwarf stages. For 10 points, name this type of nebula that consists of the ionized outer layers of a red giant and has a misleading name.
Some of these objects evolve too slowly to ever become bright enough for observation, which Alvio Renzini dubbed their "lazy" variety.
planetary nebulae [or  PNe; prompt on "(emission) nebulae"; do not accept "protoplanetary nebulae"]