Novae and Recurrent Novae
Novae were, for many years, the most prestigious stellar objects that an amateur astronomer could hope to discover. Indeed, only finding a comet, which bears the name of the discoverer, carried more kudos. Yet, essentially, a nova is simply an extreme form of cataclysmic variable (CV). Like dwarf novae and Type Ia supernovae, a binary system incorporating a hot white dwarf and a cooler secondary star is involved. In this case the secondary star can be a giant, subgiant, or dwarf star of spectral class K–M.
The IAU lists a total of 370 nonrecurring novae discovered since 1612. The orbital period of the binary system in a nova can range from that of the dwarf novae, that is, mere hours, to hundreds of days. The increase in brightness during a nova outburst is greater than that of a dwarf nova outburst, and you cannot expect to see the same star as a nova again, at least not with a so-called ‘classical’ nova.
So what happens when a nova appears in our skies? We have already seen, in...