AAS 203rd Meeting, January 2004
Session 44 Cataclysmic Variables, Novae
Poster, Tuesday, January 6, 2004, 9:20am-6:30pm, Grand Hall

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[44.06] Time Resolved H\alpha Spectroscopy of the Eclipsing Old Nova DQ Her

E. Mastrantonio (Lycoming College), A. Bianchini (University of Padova), R. Canterna (University of Wyoming)

Time resolved H\alpha VPH spectroscopic observations of the old nova DQ Her (1934) were taken during an eclipse of the white dwarf primary using the 1.82 m Mt. Ekar telescope (Asiago, Italy). The lightcurves of the H-alpha and He I line emitting regions exhibit several interesting features, including an eclipse minimum 0.02P before that of the continuum, low flux levels just before eclipse ingress and a shoulder during eclipse egress (between 1.1P and 1.15P). The latter might suggest the emergence of an emitting region--possibly the accretion stream-- during the eclipse egress that was otherwise obscured. The apparent lack of a hot spot during our observations might be explained by the presence of solar-type magnetic cycles in the secondary star, causing the mass transfer rate of the accretion stream to decrease and its impact with the disk to be less energetic. Radial velocities of ~±140 Km s-1 derived from the wings of the H\alpha profiles are consistent with the orbital motion of the white dwarf primary as suggested in the literature [1]. Instead, the peaks of the emission line seem to be formed by at least three components which, though undergoing partial eclipse, seem to change their relative intensities rather than the wavelength, as if they were emitted by regions that do not follow the orbital motion of the primary. This behavior is not obvious within the standard model of Cataclysmic Variables.

This work has been supported by NSF REU site grant AST 0097356 (University of Wyoming).

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