## Appendix A: the period-amplitude relation of novaeIn order to study the period-amplitude relation of novae, the amplitudes of all novae with known period were calculated from the maximum and minimum magnitudes quoted in the catalogue of Duerbeck (1987). The only system excluded from this investigation is GK Per because due to its evolved secondary its period is much longer than that of any other nova. The outburst amplitudes are plotted against orbital period
A linear least squares fit to the data yields a formal period-amplitude relation (shown as a solid line in Fig. 7) with an inclination of . The correlation coefficient is . The significance level at which the null hypothesis of zero correlation is disproved (see e.g. Press et al. 1986) is . (Excluding V1500 Cyg, DO Aql and HR Del leads to , and .) Since the observed amplitude of the outburst depends on the
intrinsic strength of the eruption Warner's relation indicates that the absolute magnitude increases (i.e. its numerical value decreases!) with the period by mag/hour. Within the error limits this is identical to the decrease of the observed outburst amplitude of novae found above. In conclusion we can state that the intrinsic strength of a nova outburst does not depend on the orbital period of the system. Nova theory predicts that the outburst amplitude should increase with the white dwarf mass. The independence of intrinsic outburst amplitude and period therefore also indicates that the mass distribution of the white dwarfs in novae does not depend noticeably on the period. © European Southern Observatory (ESO) 1997 Online publication: June 5, 1998 |