Spitzer detections of new dust components in the outflow of the red rectangle

Ciska Kemper, F. Markwick-Kemper, J. D. Green, E. Peeters

    Research output: Contribution to journalArticlepeer-review


    We present Spitzer high spectral resolution IRS spectroscopy of three positions in the carbon-rich outflow of post-asymptotic giant branch star HD 44179, better known as the Red Rectangle. Surprisingly, the spectra show some strong unknown mid-infrared resonances, in the 13-20 μm range. The shape and position of these resonances vary with position in the nebula, and they are not correlated with the polycyclic aromatic hydrocarbon features. We conclude that these features are due to oxygen-rich minerals, located in a region that is believed to be predominantly carbon-rich. We provide possible explanations for the presence of oxygen-rich dust in the carbon-rich outflows. Simple Mg-Fe oxides (Mg1-xFex^O) are suggested as carriers of these unidentified features. © 2005. The American Astronomical Society. All rights reserved.
    Original languageEnglish
    Pages (from-to)L119-L122
    JournalAstrophysical Journal
    Issue number2
    Publication statusPublished - 1 Aug 2005


    • Circumstellar matter
    • Dust, extinction
    • ISM: lines and bands stars: AGB and post-AGB
    • Stars: Individual (HD 44179)


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