The Astrophysical Journal, 662:651Y657, 2007 June 10 # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. BORN-AGAIN PROTOPLANETARY DISK AROUND MIRA B M. J. Ireland Planetary Science, California Institute of Technology, Pasadena, CA 91125;
[email protected] J. D. Monnier University of Michigan, Ann Arbor, MI 48109;
[email protected] P. G. Tuthill School of Physics, University of Sydney, NSW 2006, Australia;
[email protected] R. W. Cohen W. M. Keck Observatory, Kamuela, HI 96743 J. M. De Buizer Gemini Observatory, Casilla 603, La Serena, Chile C. Packham University of Florida, Gainsville, FL 32611 D. Ciardi Michelson Science Center, Caltech, Pasadena CA 91125 T. Hayward Gemini Observatory, Casilla 603, La Serena, Chile and J. P. Lloyd Cornell University, Ithaca, NY 14853 Received 2007 February 16; accepted 2007 March 10 ABSTRACT The Mira AB system is a nearby (107 pc) example of a wind accreting binary star system. In this class of system, the wind from a mass-losing red giant star (Mira A) is accreted onto a companion (Mira B), as indicated by an accretion shock signature in spectra at ultraviolet and X-ray wavelengths. Using novel imaging techniques, we report the detection of emission at mid-infrared wavelengths between 9.7 and 18.3 m from the vicinity of Mira B but with a peak at a radial position about 10 AU closer to the primary Mira A. We interpret the mid-infrared emission as the edge of an optically-thick accretion disk heated by Mira A. The discovery of this new class of accretion disk fed by M-giant mass loss implies a potential population of young planetary systems in white dwarf binaries, which has been little explored despite being relatively common in the solar neighborhood.