Open AccessAn irradiation effect in Nova DN Gem 1912 and the significance of the period gap for classical novae
Author(s) -
Retter A.,
Leibowitz E. M.,
Naylor T.
Publication year - 1999
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.1999.02704.x
Subject(s) - physics , photometry (optics) , astrophysics , orbital period , amplitude , light curve , cataclysmic variable star , nova (rocket) , irradiation , accretion disc , astronomy , stars , optics , white dwarf , nuclear physics , aeronautics , engineering
Continuous CCD photometry of the classical nova DN Gem during 52 nights in the years 1992–1998 reveals a modulation with a period of 0.127844 d. The semi‐amplitude is about 0.03 mag. The stability of the variation suggests that it is the orbital period of the binary system. This interpretation makes DN Gem the fourth nova inside the cataclysmic variable (CV) period gap, as defined by Diaz & Bruch, and it bolsters the idea that there is no period gap for classical novae. However, the number of known nova periods is still too small to establish this idea statistically. We eliminate several possible mechanisms for the variation, and propose that the modulation is driven by an irradiation effect. We find that model light curves of an irradiated secondary star fit the data well. The inclination angle of the system is restricted by this model to 10°≲ i ≲65°. We also refine a previous estimate of the distance to the binary system, and find d =1.6±0.6 kpc.