scholarly journals The Zodiacal Cloud Complex

1991 ◽  
Vol 126 ◽  
pp. 131-138
Author(s):  
A.C. Levasseur-Regourd ◽  
J.B. Renard ◽  
R. Dumont
Keyword(s):  
Optical Properties ◽  
Symmetry Plane ◽  
Ecliptic Plane ◽  
Interplanetary Dust ◽  
The Sun ◽  
Zodiacal Light ◽  
Zodiacal Cloud ◽  
Classical Models ◽  
Cloud Complex ◽  
Two Populations

AbstractThe physical properties of the interplanetary dust grains are, out of the ecliptic plane, mainly derived from observations of zodiacal light in the visual or infrared domains. The bulk optical properties (polarization, albedo) of the grains are demonstrated to depend upon their distance to the Sun (at least in a 0.1 AU to 1.7 AU range in the symmetry plane) and upon the inclination of their orbits (at least up to 22°). Classical models assuming the homogeneity of the zodiacal cloud are no longer acceptable. A hybrid model, with a mixture of two populations, is proposed. It suggests that various sources (periodic comets, asteroids, non periodic comets...) play an important role in the replenishment of the zodiacal cloud complex.

scholarly journals Optical Properties of Interplanetary Dust in the Tangential Plane

1991 ◽  
Vol 126 ◽  
pp. 199-202
Author(s):  
J.B. Renard ◽  
A.C. Levasseur-Regourd ◽  
R. Dumont
Keyword(s):  
Optical Properties ◽  
Symmetry Plane ◽  
Ecliptic Plane ◽  
Interplanetary Dust ◽  
Polarization Degree ◽  
Zodiacal Light ◽  
Tangential Plane ◽  
Zodiacal Cloud ◽  
Local Polarization ◽  
Local Intensity

AbstractLocal intensity and emissivity, and consequently local polarization degree, temperature and albedo, can be retrieved from optical and thermal observations of zodiacal light. The local polarization degree (normalized at constant solar distance and phase angle) is found to decrease with elevation above the symmetry plane of the zodiacal cloud. The heterogeneity of the cloud, established towards the symmetry pole, is here demonstrated in the tangential plane (almost perpendicular to the ecliptic plane at 1 AU). We present a map of the local polarization degree in this plane.

scholarly journals On The Gegenschein and the Symmetry Plane

1991 ◽  
Vol 126 ◽  
pp. 147-150
Author(s):  
S. S. Hong ◽  
S. M. Kwon
Keyword(s):  
Symmetry Plane ◽  
Outer Part ◽  
Ecliptic Plane ◽  
Dust Concentration ◽  
Zodiacal Light ◽  
Zodiacal Cloud ◽  
Extended Region

AbstractUsing 3-dim density models of the zodiacal cloud, we have calculated brightness of the zodiacal light over an extended region around the anti-solar point. The isophotal contours of the model Gegenscheins differ from each other, morphologically, to the degree that they can differentiate the competing density models. The recently reduced Gegenschein observations of 2° resolution clearly favour the ellipsoid-type models to the fan-types, and also suggest that the surface of the densest dust concentration in the outer part of the cloud has its ascending node at longitude 100 ± 20° and is inclined 2 ± 0°.5 with respect to the ecliptic plane.

scholarly journals Spatially Varying Optical Properties of the Zodiacal Dust

1989 ◽  
Vol 8 ◽  
pp. 267-272
Author(s):  
S. S. Hong ◽  
S. M. Kwon
Keyword(s):  
Optical Properties ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
The Sun ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
Ample Evidence ◽  
Mixing Ratios ◽  
Zodiacal Dust ◽  
Spatially Varying

AbstractAnalyses of both the zodiacal light in the visible and the zodiacal emission in the infrared have provided us with ample evidence to claim that the interplanetary dust particles are mixtures or coagulations of more than one constituents and their mixing ratios vary with the distance from the sun.

scholarly journals 1.3.3 Consequences of the Inclination of the Zodiacal Cloud on the Ecliptic

1976 ◽  
Vol 31 ◽  
pp. 121-121
Author(s):  
R. Robley
Keyword(s):  
Solar System ◽  
Exponential Distribution ◽  
Inclination Angle ◽  
Radial Direction ◽  
Heliocentric Distance ◽  
Ecliptic Plane ◽  
Interplanetary Dust ◽  
Zodiacal Light ◽  
Invariant Plane ◽  
Zodiacal Cloud

Assuming that the decrease in the density of the interplanetary dust follows an exponential distribution both in the transverse and radial direction, we can write n = no Exp(-(h/H)-(r-l/R)), where h is the distance from the ecliptic plane and r the heliocentric distance both expressed in astronomical units (a.u.); then we show that the modulation of the radiance B(90, 0) of the zodiacal light observed at the ecliptic pole defines the parameter H as a function of the inclination angle B between the zodiacal cloud and the ecliptic plane; moreover, the experimental value of the ratio B(90, 0)/B(90, 90) defines the parameter R. It can be deduced that the flatness of the zodiacal cloud, expressed by R/H, is < 5 and that the plane of symmetry of the zodiacal cloud is very close to that of the invariant plane of the solar system (B<2°).

scholarly journals Photometric Axis Measurements of the Zodiacal Light at Large Elongations

1980 ◽  
Vol 90 ◽  
pp. 45-48
Author(s):  
H. Tanabe ◽  
A. Takechi ◽  
A. Miyashita
Keyword(s):  
Spatial Distribution ◽  
Interplanetary Dust ◽  
The Sun ◽  
Zodiacal Light ◽  
The Earth ◽  
Photoelectric Measurements ◽  
Ecliptic Longitude

Measurement of the position of the photometric axis of the zodiacal light at large elongations (90 ° < λ − λ⊙ < 270°; λ:ecliptic longitude, λ⊙: ecliptic longitude of the sun) provides information about the spatial distribution of the interplanetary dust outside the orbit of the Earth. However, modern photoelectric measurements in this part are scarce, except for the Gegenschein region, because of the observational difficulty due to faintness of this part of the zodiacal light.

scholarly journals The Optical Properties of Interplanetary Dust

1991 ◽  
Vol 126 ◽  
pp. 163-170 ◽  
Author(s):  
P.L. Lamy ◽  
J.M. Perrin
Keyword(s):  
Optical Properties ◽  
Light Scattering ◽  
Phase Function ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Local Enhancement ◽  
Zodiacal Light ◽  
Laboratory Results

AbstractAfter briefly evaluating the observations of the Zodiacal Light and F-corona, we review the laboratory results on the light scattering by dust particles and the various theories which have been recently proposed. We then discuss the optical properties of the dust with emphasis on the phase function, the polarization, the color, the albedo and the local enhancement in the Gegenschein.

scholarly journals 6.1 The Zodiacal Light

1976 ◽  
Vol 31 ◽  
pp. 475-477
Author(s):  
H. Elsässer
Keyword(s):  
Interplanetary Dust ◽  
The Sun ◽  
Deep Space ◽  
Zodiacal Light ◽  
Open Questions ◽  
Long Time

As one of the most important results of what we heard in these days I consider the density law of interplanetary dust derived from zodiacal light observations by the deep space probes going out to Jupiter and going in to 0.3 AU. The dependence on the distance to the sun R seems to be nearly as R-1. This finding is in agreement with a new discussion of ground based observations which was reported by Dumont. The density law was one of the open questions for a long time; for me this represents a break-through.

2.1.8 Sources of Interplanetary Dust: Asteroids

1976 ◽  
Vol 31 ◽  
pp. 187-205 ◽  
Author(s):  
J. S. Dohnanyi
Keyword(s):  
Interplanetary Dust ◽  
Asteroid Belt ◽  
The Sun ◽  
Number Density ◽  
Zodiacal Cloud ◽  
Relative Contribution ◽  
Potential Source ◽  
Asteroidal Belt ◽  
Pioneer 10

AbstractThe asteroid belt is examined as a potential source of interplanetary dust. Using results from the Pioneer-10 experiments the relative contribution of asteroidal and cometary particles to the Zodiacal cloud is estimated using methods developed in earlier studies of meteoroidal collisions (collisional model). It is found that the contribution of asteroidal particles to dust in the asteroidal belt is small compared with the number density of cometary type particles. Similar conclusions apply to the Zodiacal cloud between the sun and the asteroid belt. When definitive criteria for differentiating between comets and asteroids become available, a reexamination of some of our conclusions may become necessary.The distribution of asteroidal rotations is analyzed; it is found that the gross features of the distribution can be reproduced using the collisional model.

scholarly journals The Infrared Zodiacal Light

1991 ◽  
Vol 126 ◽  
pp. 171-178
Author(s):  
Martha S. Hanner
Keyword(s):  
Optical Properties ◽  
Solar Eclipse ◽  
Heliocentric Distance ◽  
Thermal Emission ◽  
Diffuse Radiation ◽  
Interplanetary Dust ◽  
Zodiacal Light

AbstractThermal emission from interplanetary dust is the main source of diffuse radiation atλ5-50 μm. Analysis of infrared sky maps from IRAS and ZIP lead to the result that the average optical properties of the dust change with heliocentric distance. The present uncertainties in calibration should be resolved by COBE. Existence of a dust sublimation zone at 4 solar radii awaits confirmation at the next solar eclipse.

scholarly journals Dust Near the Sun

1996 ◽  
Vol 150 ◽  
pp. 315-320
Author(s):  
I. Mann
Keyword(s):  
Near Infrared ◽  
Dust Cloud ◽  
Interplanetary Dust ◽  
Present Knowledge ◽  
The Sun ◽  
Zodiacal Light ◽  
Particle Properties ◽  
In Situ Experiments ◽  
Near Future

AbstractYielding the inner continuation of the interplanetary dust cloud, the dust at about 0.3 AU and closer to the Sun is studied under observing conditions different from those of the Zodiacal light. The F-coronal brightness indicates its optical particle properties as well as its overall spatial distribution. The present knowledge is based on visible and near infrared F-coronal observations and may be improved from data of the SOHO satellite in the near future. Some dynamical effects become particulary important for sub-μm particles in the solar vicinity. However, these particles seem to have only a small effect on the observable corona brightness, but are more accessible to in-situ experiments.

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