Astron. Astrophys. 326, 271-276 (1997)

Mid infrared spectral observations of UX Orionis ^*

H.-G. Reimann ¹, J. Gürtler ¹, C. Friedemann ¹ and H. U. Käufl <sup>2

1</sup> Friedrich-Schiller-Universität Jena, Astrophysikalisches Institut und Universitäts-Sternwarte, Schillergäßchen 2, D-07745 Jena, Germany
² European Southern Observatory, D-85748 Garching, Germany

Received 21 October 1996 / Accepted 25 April 1997

Abstract

The circumstellar infrared emission of the evolutionarily young irregular variable UX Orionis has been investigated. The observed spectral energy distribution has been modelled by radiative transfer calculations and the parameters for a spherically symmetric envelope have been derived. Two mid-infrared spectra of UX Orionis were obtained with the T hermal I nfrared M ultim ode I nstrument (TIMMI) at the ESO 3.6-m telescope. The spectra show the presence of a nearly structureless silicate emission band. Comparison with laboratory data indicates that the circumstellar silicate grains should have radii of 0.75-1 µ m.

Key words: stars: individual: UX Ori stars: circumstellar matter (ISM:) dust, extinction infrared: stars

* Based on observations collected at the European Southern Observatory, La Silla, Chile.

Send offprint requests to: H.-G. Reimann

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Contents

• 1. Introduction
• 2. Observations and data reduction
• 3. Modelling of the circumstellar dust shell
  • 3.1. Available optical and infrared data
  • 3.2. A spherically symmetric circumstellar shell
• 4. Modelling of the 10-µ m silicate emission band
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: April 20, 1998
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