Spectroscopic Study of Q Cygni: Surprises from an Old Nova

Abstract

We present a time-resolved spectroscopic study of Q Cyg (Nova Cyg 1876), determining a period of P = 10.08 hr for the system. Our data also reveal P Cygni profiles in the He I λλ5876 and 7065 lines and occasionally in the Hα line. Although P Cygni profiles commonly appear in the UV resonance lines of nova-like cataclysmic variables, only BZ Cam was previously known to exhibit a rapidly variable wind, which leaves its signature in time-resolved optical spectral lines. A comparison between BZ Cam and Q Cyg reveals striking similarities between the two systems. The origin of the outflow in Q Cyg and a possible correlation of the P Cygni profiles with the system's optical state are discussed.