Ueta, T. and Speck, A. K. and Stencel, R. E. and Herwig, F. and Gehrz, R. D. and Szczerba, R. and Izumiura, H. and Zijlstra, A. A. and Latter, W. B. and Matsuura, M. and Meixner, M. and Steffen, M. and Elitzur, M. (2006) Detection of a far-infrared bow shock nebula around R Hya: The first MIRIAD results. Astrophysical Journal, 648 (1). L39-L42. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:UETapjl06
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We present the first results of the MIRIAD (MIPS InfraRed Imaging of AGB Dust shells) project using the Spitzer Space Telescope. The primary aim of the project is to probe the material distribution in the extended circumstellar envelopes (CSEs) of evolved stars and recover the fossil record of their mass-loss history. Hence, we must map the whole of the CSEs plus the surrounding sky for background subtraction while avoiding the central star that is brighter than the detector saturation limit. With our unique mapping strategy, we have achieved better than 1 MJy sr-1 sensitivity in 3 hr of integration and successfully detected a faint (<5 MJy sr-1), extended (~400") far-infrared nebula around the asymptotic giant branch (AGB) star R Hya. Based on the parabolic structure of the nebula, the direction of the space motion of the star with respect to the nebula shape, and the presence of extended HΩ emission cospatial to the nebula, we suggest that the detected far-IR nebula is due to a bow shock at the interface of the interstellar medium and the AGB wind of this moving star. This is the first detection of the stellar-wind bow shock interaction for an AGB star and exemplifies the potential of Spitzer as a tool to examine the detailed structure of extended far-IR nebulae around bright central sources.
|Additional Information:||© 2006 The American Astronomical Society. Received 2006 June 9; accepted 2006 July 13; published 2006 August 10. This work is based on observations made with the Spitzer Space Telescope, which is operated by the JPL/Caltech under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. We also acknowledge additional support for the following individuals: an NPP Research Fellowship Award to T. Ueta, NASA ADP grant NAG 5-12675 to A.K. Speck, the LDRD program (20060357ER) at LANL for F. Herwig, NASA contract 1215746 issued by JPL/Caltech to R.D. Gehrz, grant 2.P03D.017.25 to R. Szczerba, a Grant-in-Aid (C) from JSPS (17540221) to H. Izumiura, JSPS for M. Matsuura, and NSF grant AST 05-07421 to M. Elitzur. We thank C.J. Wareing for sharing his insights on the stellar-wind bow shocks with us.|
|Subject Keywords:||circumstellar matter—infrared: stars—ISM: structure—stars: AGB and post-AGB—stars: individual (R Hydrae)—stars: mass loss|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Lindsay Cleary|
|Deposited On:||14 Nov 2006|
|Last Modified:||26 Dec 2012 09:17|
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