2. The observed period distribution
The observed orbital periods of novae are listed in Table 1 and their distribution is shown in Fig. 2. Most of the data are extracted from the compilations of Ritter & Kolb (1995), Duerbeck (1987), Warner (1987) and Bruch & Engel (1994). Additionally, the recently determined periods of DO Aql and V849 Oph (Shafter et al. 1993), V368 Aql (Diaz & Bruch 1994) and V909 Sgr and V4077 Sgr are listed. For the last two systems periods are suggested in unpublished photometric data obtained by one of us (MD) at LNA. They still require confirmation. The long periods of DI Lac, V841 Oph and GK Per indicate that their secondary components have already evolved away from the main sequence. In these cases the relations for the mass transfer between the components to be used in Sect. 4 are not valid. Therefore, we cannot regard nova systems with evolved secondaries [and long () orbital periods] here. This leaves us with a sample of 28 novae on which the observed period distribution to be used here is based.
Table 1. Inventory of classical novae with known orbital periods
Apart from the periods, Table 1 contains some further relevant information for each system in the sample. In particular, the - and - times, the outburst amplitude, the quiescent magnitude along with the colour excess, if known, and the observational feature from which the period can be derived are listed. A search for correlations between the period and other directly observable items revealed no dependence of the decay time or the expansion velocity of the shell on the period. But a significant correlation between the nova amplitude and the orbital period exists (see Appendix A).
© European Southern Observatory (ESO) 1997
Online publication: June 5, 1998