Be-ness is not only an evolutionary stage in the lives of some rapidly rotating hot B-type stars but also a transient phenomenon that may come and go over the years for the same star. Several reasons have been proposed to explain the behavior of these stars and are still in debate.
Mira variables are the longest-observed class of stars for which we have long-term quantitative data that allow us to study their behavior over centuries-long periods of time. Fortunately for us, they're also easy to observe and monitor, having some of the largest amplitudes of all variables, and hundreds of them are bright enough that they're within reach of astronomers with modest telescopes.
Multi-epoch animations for six UV Ceti (flare) stars. Because they are red dwarf stars, the known UV Ceti stars are confined to the immediate solar neighborhood. Many such stars have relatively large proper motions. Among the UV Ceti stars, WX UMa has the largest proper motion -- over five arcseconds per year. This means that charts for these stars must be updated occasionally to reflect their changing positions.
All of the following material was taken directly from William Tyler Olcott's book entitled Star Lore of All Ages, published in 1911 by The Knickerbocker Press. William Tyler Olcott was the founder of the AAVSO in 1911.
V723 Cas was discovered by M. Yamamoto, Okazaki, Aichi, Japan, on 1995 August 24.57 UT at photographic magnitude 9.2. The finding was made using a 200-mm f/4.0 lens, PO0 filter, and T-Max 400 film. A report by G.V. Williams of the Harvard-Smithsonian Center for Astrophysics shows percursory evidence of this nova located on the Palomar red plate of magnitude 18-19, as seen using the Digital Sky Survey (AAVSO Alert Notices 213, 214, 217, 218, 230; IAUC 6213).
A 1994 Hubble Space Telescope image of the expanding shell of gas expelled by Nova Cygni 1992. Credit: NASA, ESA, HST, F. Paresce, R. Jedrzejewski (STScI)
