Abstract
We present broadband 24, 70, and 160 μm photometry and 5-35 and 55-90 μm spectra of the eruptive variable V4332 Sgr from Spitzer observations. The distinguishing feature of the 5-35 μm spectrum is an unusually broad absorption feature near 10 μm at the position generally associated with silicate-rich dust. Through radiative transfer modeling, we show that this broad feature cannot arise from silicates alone but requires the inclusion of alumina (Al 2O3) as a dust condensate. The case for including Al 2O3 is further strengthened by the presence of the AlO radical, a potentially important molecule in forming Al2O 3. The present detection indicates that porous alumina manifests itself through a broadening of the 9.7 μm silicate feature and additionally displays, on the shoulder of the silicate feature, a component at ∼11.5 μm. We discuss how further observations of V4332 Sgr may have the potential of verifying some general predictions of the dust condensation process.
Original language | English (US) |
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Pages (from-to) | L25-L28 |
Journal | Astrophysical Journal |
Volume | 666 |
Issue number | 1 PART 2 |
DOIs | |
State | Published - 2007 |
Keywords
- Cataclysmic variables-Stars
- Color figures
- Individual (V4332 Sagittarii) Online material
- Infrared
- Stars-Novae
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science