Spectropolarimetric observations of cool DQ white dwarfs

Abstract

Aims. Following our recent discovery of a new magnetic DQ white dwarf (WD) with CH molecular features, we report the results for the rest of the DQ WDs from our survey. Methods. We use high signal-to-noise spectropolarimetric data to search for magnetic fields in a sample of 11 objects. Results. One object in our sample, WD1235+422, shows the signs of continuum circular polarization that is similar to some peculiar DQs with unidentified molecular absorption bands, but the low signal-to-noise ratio and spectral resolution of these data make more observations necessary to reveal the true nature of this object. © 2013 ESO.