Variability of 3 protoplanetary nebulae

We present new photometric data and analyze long-term UBV observations of three candidates for protoplanetary nebulae - F supergiants with infrared excesses at high Galactic...我们报道了全新的测光数据，并对三颗原行星状星云（protoplanetary nebulae）候选体的长期UBV测光观测展开分析——这类候选体均为带有红外超（infrared excesses）的F型超巨星（F supergiants），处于高银道（Galactic）……