Zodiacal emission. II. Dust near ecliptic
- California Univ., Berkeley (USA)
The location and brightness of the peak zodiacal emission are derived from IRAS observations of the diffuse infrared background radiation. A uniform ellipsoid geometrical model is fitted to the latitudes of peak brightness, from which the orientation of the surface of maximum dust density near the earth's orbit is derived. Deviations from the uniform ellipsoid indicate that this surface bends toward the invariable plane of the solar system beyond 2.5 AU from the sun. The variations of the peak zodiacal emission brightness with solar elongation and observation date allow two independent determinations of the gradient of the volume emissivity of interplanetary dust. Combined with theoretical calculations of the infrared emission from silicate and graphite grains heated by the sun, the gradient of the dust density is found to be n proportional to r exp (-1.1 + or - 0.2). Systematic brightness variations with ecliptic longitude reveal two potential asymmetries in the dust complex: excess emission following the earth in its orbit, and excess emission along lines of sight with ecliptic longitude lambda = 190 + or - 20 deg and solar lambda about 100 deg. 57 refs.
- OSTI ID:
- 5756434
- Journal Information:
- Astrophysical Journal; (USA), Vol. 369; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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GENERAL PHYSICS
INTERPLANETARY SPACE
COSMIC DUST
ZODIACAL LIGHT
BRIGHTNESS
COORDINATES
INFRARED RADIATION
LUMINOSITY
SOLAR SYSTEM
STAR MODELS
DUSTS
ELECTROMAGNETIC RADIATION
MATHEMATICAL MODELS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RADIATIONS
SPACE
640107* - Astrophysics & Cosmology- Planetary Phenomena