Howell, Steve B. and Brinkworth, Carolyn and Hoard, D. W. and Wachter, Stefanie and Harrison, Thomas and Chun, Howard and Thomas, Beth and Stefaniak, Linda and Ciardi, David R. and Szkody, Paula and van Belle, Gerard (2006) First Spitzer Space Telescope Observations of Magnetic Cataclysmic Variables: Evidence of Excess Emission at 3-8 μm. Astrophysical Journal Letters, 646 (1). L65-L68. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110630-110108077
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We present the first observations of magnetic cataclysmic variables using the Spitzer Space Telescope. We used the Infrared Array Camera to obtain photometry of the Polars EF Eri, GG Leo, V347 Pav, and RX J0154.0-5947 at 3.6, 4.5, 5.8, and 8.0 μm, respectively. In all of our targets, we detect excess mid-infrared emission over that expected from the component stars alone. We explore the origin of this IR excess by examining bremsstrahlung, cyclotron emission, circumbinary dust, and L/T brown dwarf secondary stars. Bremsstrahlung and cyclotron emission appear unlikely to be significant contributors to the observed fluxes. At present, the most likely candidate for the excess emission is dust that is probably located in a circumbinary disk with an inner temperature near 800 K. However, a simple dust disk plus any reasonable low-mass or brown dwarf-like secondary star is unable to fully explain the observed flux densities in the 3-8 μm region.
|Additional Information:||© 2006 American Astronomical Society. Received 2006 January 24; accepted 2006 June 8; published 2006 July 12. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, Caltech, under NASA contracts 1407 and 960785. We thank the Spitzer Science Center (SSC) Director for his generous allocation of observing time for the NASA/NOAO Spitzer Space Telescope Observing Program for Students and Teachers. NOAO, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the NSF, has provided many in-kind contributions for which the first author is grateful. Michelle Smith and Kimmerlee Johnson from Great Falls High School, Great Falls, Montana, assisted in the data processing. We also thank the SSC folks for their hospitality during our visit. The TLRBSE Project is funded by the NSF under ESI 0101982 through the AURA/NSF Cooperative Agreement AST-9613615. This work makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and IPAC/ Caltech, funded by NASA and the NSF. C. B. acknowledges support from the SSC Enhanced Science Fund, NASA’s Michelson Science Center, and the Spitzer Director’s Discretionary funds.|
|Subject Keywords:||stars: individual (EF Eridani, GG Leonis, V347 Pavonis, RX J0154.0–5947); stars: low-mass, brown dwarfs|
|Official Citation:||First Spitzer Space Telescope Observations of Magnetic Cataclysmic Variables: Evidence of Excess Emission at 3-8 μm Steve B. Howell, Carolyn Brinkworth, D. W. Hoard, Stefanie Wachter, Thomas Harrison, Howard Chun, Beth Thomas, Linda Stefaniak, David R. Ciardi, Paula Szkody, and Gerard van Belle doi: 10.1086/506558|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||30 Jun 2011 18:28|
|Last Modified:||26 Dec 2012 13:21|
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