Photometric Properties of Classical Novae at Minimum

Abstract

Our present knowledge of the number of Galactic classical novae is briefly reviewed, and recurrent nova candidates are listed. The photometric behaviour of novae at minimum is studied, and the existence of a general decline of about dm / d log t = 1.3 (decline in magnitudes for each ten-fold temporal separation from the outburst, measured in years) is established. A small group of novae has post-outburst magnitudes which are noticeably brighter than their pre-outburst magnitudes, and are identified as short-period (magnetic) systems. Both groups show a similar brightness decline. Number counts N(m) of cataclysmic binaries may be helpful for solving the problem of recurrence times and hibernation properties of novae. The magnitude limit of existing complete samples, however, is too bright to draw firm conclusions.