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Quasi–periodic Outburst Activity of Novae at Minimum

Published online by Cambridge University Press:  12 April 2016

M. Della Valle  and
M. Calvani
M. Della Valle
Affiliation:
International School of Advanced Studies, Trieste Dipartimento di Astronomia, Università di Padova
M. Calvani
Affiliation:
International School of Advanced Studies, Trieste

Abstract

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In this paper we present the statistical analysis of historical light curves of 8 old novae, performed through a Fourier analysis on ~ 1600 no-equispaced (in the time) observations published by Steavenson between 1921 and 1953. The results seems to support the existence of a semiregular variability on typical timescales of 50d ÷ 100d and amplitude of ~ 0.3 ± 0.1 magnitudes.

At present the largest body of data concerning the photometric behaviour of novae at minimum, is due to the pioneering works by Steavenson (1920→1950) and also to Robinson’s compilation (1975) of 33 preeruption lightcurves of novae.

Besides testing the evolutionary models, such as the Hibernation Scenario (Shara et al. 1986), the importance of very long term observations of novae at minimum, has been recently pointed out by Bianchini (1987) and Warner (1988) in close connection to the possible detection of solar-type cycles of activity of the secondary. In spite of these considerations an interesting body of ~ 1000 homogenous observations of 5 posteruption lightcurves provided by Steavenson between 1920 to 1950 (published on M.N.R.A.S) has been neglected and only recently recovered (Delia Valle 1988).

The aim of our analysis is:

  1. a) to verify possible presence of Dwarf Nova activity

  2. b) to confirm on the basis of a larger sample of objects, the existence of semiregular variability as observed in Q Cyg 1876 (Shugarov 1983) and v841 Oph (Della Valle and Rosino 1987).

In this contribute we present only the preliminary results of our Fourier’s analysis, performed by adopting the procedure suggested by Deeming (1975) to analyse data taken at unequally spaced time intervals, whereas a more complete analysis will be presented in a forthcoming paper.

Type
1a. Basic Properties of Novae
Information
International Astronomical Union Colloquium , Volume 122: Physics of Classical Novae , 1990 , pp. 48 - 49
Copyright
Copyright © Springer-Verlag 1990

References

- Bianchini, A. 1987, Proceedings of “2nd Italian Meeting on Infrared Astronomy” Vulcano 1987.Google Scholar
- Deeming, T.J. 1975, Astrophys. Space Sci. 36 137 CrossRefGoogle Scholar
- Della Valle, 1988, Ph.D. DissertationGoogle Scholar
- Della Valle, M., Rosino, L. 1987, IBVS 2995 Google Scholar
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- Shara, M.M., Livio, M., Moffat, A.F., Orio, M. 1986, Ap.J., 311 163 CrossRefGoogle Scholar
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- Warner, B. 1988, Nature, 336 129 CrossRefGoogle Scholar