2008/02/18 by John H. Debes, J. H. Debes, Mercedes López-Morales +1 · 1 citation
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Equivalent width #K-line #Line (geometry) #Line width #Spectral line #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/587550
14 pages, 4 figures, Accepted to ApJL
arxiv created 2008/02/18 · openalex publication_date 2008/03/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
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.