Earth, Moon, and Planets

, Volume 79, Issue 1, pp 247–264

Thermal Emission From The Dust Coma Of Comet Hale-Bopp And The Composition Of The Silicate Grains

  • M. S. Hanner
  • R. D. Gehrz
  • D. E. Harker
  • T. L. Hayward
  • D. K. Lynch
  • C. C. Mason
  • R. W. Russell
  • D. M. Williams
  • D. H. Wooden
  • C. E. Woodward
Article

DOI: 10.1023/A:1006201820477

Cite this article as:
Hanner, M.S., Gehrz, R.D., Harker, D.E. et al. Earth, Moon, and Planets (1997) 79: 247. doi:10.1023/A:1006201820477

Abstract

The dust coma of comet Hale-Bopp was observed in the thermal infrared over a wide range in solar heating (R = 4.9–0.9 AU) and over the full wavelength range from 3 μm to 160 μm. Unusual early activity produced an extensive coma containing small warm refractory grains; already at 4.9 AU, the 10 μm silicate emission feature was strong and the color temperature was 30% above the equilibrium blackbody temperature. Near perihelion the high color temperature, strong silicate feature, and high albedo indicated a smaller mean grain size than in other comets. The 8–13 μm spectra revealed a silicate emission feature similar in shape to that seen in P/Halley and several new and long period comets. Detailed spectral structure in the feature was consistent over time and with different instruments; the main peaks occur at 9.3, 10.0 and 11.2 μm. These peaks can be identified with olivine and pyroxene minerals, linking the comet dust to the anhydrous chondritic aggregate interplanetary dust particles. Spectra at 16–40 μm taken with the ISO SWS displayed pronounced emission peaks due to Mg-rich crystalline olivine, consistent with the 11.2 μm peak.

Comet Hale-Boppinfrareddustsilicates

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • M. S. Hanner
    • 1
  • R. D. Gehrz
    • 2
  • D. E. Harker
    • 3
  • T. L. Hayward
    • 4
  • D. K. Lynch
    • 5
  • C. C. Mason
    • 2
  • R. W. Russell
    • 5
  • D. M. Williams
    • 2
  • D. H. Wooden
    • 6
  • C. E. Woodward
    • 3
  1. 1.MS 183-501 Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaUSA
  2. 2.Astronomy DepartmentUniversity of MinnesotaMinneapolisUSA
  3. 3.Wyoming Infrared Observatory, Physics and Astronomy DepartmentUniversity of WyomingLaramie
  4. 4.Astronomy DepartmentCornell UniversityIthacaUSA
  5. 5.Aerospace CorporationLos AngelesUSA
  6. 6.MS 245-6 NASA Ames Research CenterMoffett FieldUSA