Spitzer observations of V4332 sagittarii: Detection of alumina dust

D. P.K. Banerjee, K. A. Misselt, K. Y.L. Su, N. M. Ashok, P. S. Smith

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

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 languageEnglish (US)
Pages (from-to)L25-L28
JournalAstrophysical Journal
Volume666
Issue number1 PART 2
DOIs
StatePublished - 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

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