Key points are not available for this paper at this time.
The secondary star of the dwarf nova Z Cha has been detected with the CCD spectrograph of the CTIO 4 m telescope. The TiO λ7150/λ7650 band ratio implies a Boeshaar spectral type of M5.5 for the secondary star, which contributes ≡15% of the light at λ7500. The absolute absorption strength of TiO is very weak on the side of the star that faces the white dwarf and accretion disk. The authors use cross-correlation techniques to measure the velocity of the secondary star as a function of orbital phase, and examine the photometric variations of spectral features with orbital phase. They also model the phase variations of the absorption features in terms of their surface distribution on the secondary star, evaluate a correction to the observed K velocity to account for the nonuniform line strength, and derive physical parameters of the Z Cha system.
Wade et al. (Fri,) studied this question.