SIMBAD references

The pulsating white dwarf G29-38 possesses a dust disk and metal lines attributed to the accretion of its disk material. Von Hippel and Thompson have reported variability in the equivalent width of G29-38's Ca II K line on a timescale of days. We use high-resolution optical spectroscopy of G29-38's Ca II K line to test this observation. Over 6 days spanning 2007 June to 2007 October we see no evidence for variability in the equivalent width of the Ca II K line. We also sample the variability of the Ca II K line over integrated timescales of ∼100-500 s, where errors from incomplete coverage of pulsation modes are predicted to be ∼8%-15%. We find that the scatter of the equivalent widths over this time period is consistent with measurement errors at the 7% level, slightly weaker than predicted but within the uncertainties of predictions. Weaker Ca and Mg lines observed show no significant variability on yearly timescales over 10 years based on our data and other high-resolution spectra. We conclude that further study is warranted to verify whether the accretion onto G29-38 is variable.