Astron. Astrophys. 319, 617-629 (1997)

H₂O⁺, CO⁺, and dust in Comet P/Swift-Tuttle ^*

K. Jockers ¹ and T. Bonev <sup>2

1</sup> Max-Planck-Institut für Aeronomie, Postfach 20, D-37189 Katlenburg-Lindau, Germany
² Institute of Astronomy, Bulgarian Academy of Sciences, Tsarigradsko chaussée 72, 1784 Sofia, Bulgaria

Received 22 March 1996 / Accepted 9 August 1996

Abstract

Comet P/Swift-Tuttle was observed in the light of H₂ O , CO and continuum with the 2-m telescope of the Bulgarian National Astronomical Observatory (BNAO) on Nov. 25, 1992. We present column density maps of the H₂ O and CO ions and a map of the product of filling factor, geometrical albedo, and phase function. The H₂ O ions are more concentrated toward the nucleus than CO . The ion distributions are in close agreement with magnetohydrodynamic models including photochemistry of H₂ O , CO and their parents. The color of a spiral dust jet present in the continuum image was redder than the color of the ambient dust. The observations demonstrate the similarity between comets P/Halley and P/Swift-Tuttle.

Key words: comets: general; P/Halley; 109P/Swift-Tuttle

* Based on observations at the Bulgarian National Astronomical Observatory

Send offprint requests to: K. Jockers

Contents

• 1. Introduction
• 2. Observations and reduction
  • 2.1. The instrumentation
  • 2.2. The observations
  • 2.3. Data reduction
    • 2.3.1. Bias, flat fields, and sky background
    • 2.3.2. Extinction correction
    • 2.3.3. Subtraction of dust continuum
    • 2.3.4. Reduction to ion column densities and solar continuum
• 3. Results
• 4. Discussion
  • 4.1. The ions
    • 4.1.1. Spatial distribution of H₂ O and CO
    • 4.1.2. Tail structures
    • 4.1.3. The ion flux
    • 4.1.4. The CO to H₂ O ratio
  • 4.2. The dust
    • 4.2.1. The dust color
    • 4.2.2. Radial profiles and dust production
• 5. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998
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