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Published February 10, 2008 | Published
Journal Article Open

Near-infrared spectroscopic study of the accreting magnetic white dwarf SDSS J121209.31+013627.7 and its substellar companion

Abstract

The nature of the excess near-infrared emission associated with the magnetic white dwarf commonly known as SDSS 1212 is investigated primarily through spectroscopy, and also via photometry. The inferred low-mass secondary in this system has been previously detected by the emission and variation of Hα, and the 1-2.5 μm spectral data presented here are consistent with the presence of a late L or early T dwarf. The excess flux seen beyond 1.5 μm in the phase-averaged spectrum is adequately modeled with an L8 dwarf substellar companion and cyclotron emission in a 7 MG magnetic field. This interesting system manifests several observational properties typical of polars, and is most likely an old interacting binary with a magnetic white dwarf and a substellar donor in an extended low state.

Additional Information

© 2008. The American Astronomical Society. Received 2007 August 7, accepted for publication 2007 October 27. This paper benefitted greatly from the insight of an anonymous referee, to whom the authors are commensurately grateful. The authors would like to thank the following people: B. Rodgers, G. Doppman, and K. Labrie (for much appreciated help in understanding and processing GNIRS data); A. Stephens (for NIRI particulars); P. Hirst (for WFCAM particulars); and S. Leggett (for a useful discussion regarding photometric calibration errors). M. R. Burleigh is supported by a UK Science and Technology Facilities Council Advanced Fellowship. Spectroscopic observations for this paper were taken as part of the Gemini Director's Discretionary Time GS-2006A-DD-5. Photometric observations were obtained as part ofGemini Queue ProgramGN-2006A-Q-51 and UKIRT Service Program 1653. The Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the NationalResearchCouncil (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), andCONICET (Argentina). The United Kingdom Infrared Telescope is operated by the Joint Astronomy Centre on behalf of the UK Particle Physics and Astronomy Research Council. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. This paper has made use of the Aladin Sky Atlas operated at CDS, Strasbourg, France.

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August 22, 2023
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