Spectropolarimetric observations of cool DQ white dwarfs
T. Vornanen1, S. V. Berdyugina2,3 and A. Berdyugin4
1 Department of Physics and Astronomy, University of Turku, Vaisalantie 20, 21500 Piikkio, Finland
2 Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, 79104 Freiburg, Germany
3 NASA Astrobiology Institute, Institute for Astronomy, University of Hawaii, HI, USA
4 Finnish Center for Astronomy with ESO, University of Turku, Vaisalantie 20, 21500 Piikkio, Finland
Received: 24 October 2012
Accepted: 16 July 2013
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.
Key words: molecular processes / white dwarfs / magnetic fields
© ESO, 2013