Comet Halley - Spatial and temporal variability of the silicate emission feature

Journal Article · Thu Jan 31 23:00:00 EST 1991 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115716· OSTI ID:5701067

Ryan, E V; Campins, H ^[1]

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1. Planetary Science Institute, Tucson, AZ (USA) Florida Univ., Gainesville (USA)

Narrow- and broadband photometry of Comet Halley covering the wavelength range 2-20 microns was obtained at the NASA Infrared Telescope Facility (IRTF) both preperihelion (UT 1986 January 17 and 18) and postperihelion (UT 1986 March 3-5). Strong features at 10 and 20 microns, indicative of silicate emission, were evident in the data. In addition to day-to-day variations in brightness at all wavelengths, changes were observed in the strength of the silicate emission feature on timescales as short as 3 hr. While the strength of the 10-micron feature varied with location in the coma, no such variability was observed in the shape of this emission feature, in agreement with higher spectral resolution observations (Campins and Ryan, 1989). Calculated color temperatures indicate that brightness and temperature do not correlate directly, i.e., brighter did not necessarily imply hotter dust grains. These observations are used to refine a relation between the color temperature of the dust and the heliocentric distance derived by Tokunaga et al. (1988). 17 refs.

• OSTI ID: 5701067
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 101; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640107* -- Astrophysics & Cosmology-- Planetary Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BRIGHTNESS
COMETS
COSMIC DUST
DUSTS
ELECTROMAGNETIC RADIATION
EMISSION SPECTRA
HALLEY COMET
INFRARED RADIATION
INTERPLANETARY SPACE
OPTICAL PROPERTIES
OXYGEN COMPOUNDS
PHOTOMETRY
PHYSICAL PROPERTIES
RADIATIONS
SILICATES
SILICON COMPOUNDS
SPACE
SPECTRA
SPECTROSCOPY
TELESCOPES
THERMAL RADIATION
VARIATIONS