Metals in the Variable DA G29-38

G29-38 (WD2326+049) is one of the brighter members of the class of variable DA or ZZ Ceti stars. It has one of the largest amplitudes in its variations and shows the typical complex variable lightcurves of other largeamplitude DAVs. Zuckerman and Becklin (1987) found an infrared excess in the stars spectrum above 2, µm. Two different models have been proposed to explain this excess: a brown dwarf companion or a near-by dust cloud. The Whole Earth Telescope observed this star in 1988 and Winget et al. (1990) reported a large phase change in the largest amplitude oscillation, indicating the presence of a massive companion. On the other hand, radial velocity measurements showed that there is no massive companion in the system, although a low-mass orbiting object is still possible (Barnbaum and Zuckerman 1992). However, recent photometric observations over a five year time span (Kleinman et al. 1994) did not show any evidence of orbital motion in the system.