Stories by Robert P. Kraft

They are of three main types: dwarf novae, novae and supernovae. Recent studies indicate that the typical nova or dwarf nova is the volatile member of an unusual and closely coupled star pair

Because the rate at which a cepheid variable star pulsates is related to its luminosity, it serves as an astronomical yardstick. Corrections in the yardstick have again raised estimates of the age of the universe