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 21. Light of the Night Sky / Lumière du Ciel Nocturne

1997 ◽  
Vol 23 (1) ◽  
pp. 231-236
Author(s):  
Christoph Leinert
Keyword(s):  
Interstellar Dust ◽  
Thermal Emission ◽  
Scattered Light ◽  
Diffuse Radiation ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
Extragalactic Background Light ◽  
Night Sky

The light of the night sky is a difficult to disentangle mixture of tropospherically scattered light, airglow, zodiacal light (including the thermal emission by interplanetary dust particles), unresolved stellar light, diffuse scattering and emission by interstellar dust and gas, and finally an extragalactic component. It has the reputation of being a very traditional field of astronomy, which certainly is true if we look at the long history of the subject. The recent renewed interest in this topic, which continued during this triennium, appears mainly to come from three sources: - first from the impressive results of the IRAS and COBE infrared satellites. They brought to general consciousness the fact that the infrared sky is characterised by strong emission from interplanetary and interstellar dust, and made clear that this emission may interfere with the study of faint interesting sources. - then from the development of sensitive detectors and arrays for essentially all of the wavelength range to be covered in this report, from the Lyman limit to ≈ 300 μm. Now the difficult measurements of the ultraviolet diffuse radiation and of the extragalactic background light in the infrared cosmological windows around 3 μm and 200 μm have become feasible and state of the art projects. - finally, the threat to astronomical observations arising from man-made development and lighting has become important enough to further studies of uncontaminated and contaminated night sky brightnesses. This report will refer mainly to those areas and is meant to highlight noteworthy developments. It was prepared with the help of Drs. Bowyer and Mattila.

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 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 COMMISSION 21: LIGHT OF THE NIGHT SKY

2008 ◽  
Vol 4 (T27A) ◽  
pp. 171-173
Author(s):  
Adolf N. Witt ◽  
Jayant Murthy ◽  
Bo Å. S. Gustafson ◽  
W. Jack Baggaley ◽  
Eli Dwek ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Thermal Emission ◽  
Interplanetary Dust ◽  
Zodiacal Light ◽  
Microwave Background ◽  
Interstellar Gas ◽  
Milky Way Galaxy ◽  
Thermal Emissions ◽  
Night Sky ◽  
Night Sky Brightness

Commission 21 consists of IAU members and consultants with expertise and interest in the study of the light of the night sky and its various diffuse components, at all accessible electromagnetic frequencies. In cosmic distance scales, the subjects of Commission 21 range from airglow and tropospheric scattering in Earth's atmosphere, through zodiacal light in the solar system, including thermal emission from interplanetary dust, integrated starlight in the Milky Way galaxy, diffuse galactic light due to dust scattering in the galactic diffuse interstellar medium, thermal emissions from interstellar dust and free free emission from ionized interstellar gas, to various diffuse extragalactic background sources, including the cosmologically important cosmic microwave background (CMB). Observations of the diffuse night sky brightness at any frequency typically include signals from several of these sources, and it has been the historic mandate of Commission 21 to foster the necessary collaboration of experts from the different astronomical sub-disciplines involved.

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 Evidence that the Properties of Interplanetary Dust Beyond 1 AU are Not Homogeneous

1980 ◽  
Vol 90 ◽  
pp. 71-74 ◽  
Author(s):  
Donald W. Schuerman
Keyword(s):  
Cross Section ◽  
Heliocentric Distance ◽  
Interplanetary Dust ◽  
Scattering Cross Section ◽  
Zodiacal Light ◽  
Dust Density ◽  
Scattering Cross ◽  
Pioneer 10

Traditionally, earth-based observations of the zodiacal light (ZL) require two assumptions for further analysis: (A1) the dust density (n) is a power of heliocentric distance (R), n ∝ R−ν; (A2) the nature (scattering cross section, σ) of the dust is independent of location, σ(r,h,θ)=σ(θ). Observations from Pioneer 10 do not verify these assumptions.

scholarly journals Dynamics of Micrometeoroids

1980 ◽  
Vol 90 ◽  
pp. 293-298 ◽  
Author(s):  
E. Grün ◽  
H. A. Zook
Keyword(s):  
Heliocentric Distance ◽  
Ecliptic Plane ◽  
Interplanetary Dust ◽  
Spatial Density ◽  
Orbital Elements ◽  
Zodiacal Light ◽  
Consistent Picture ◽  
Time Variations ◽  
Pioneer 10

Recent observations of zodiacal light have established a reliable and consistent picture of the spatial distribution of interplanetary dust in the ecliptic plane. The spatial density nr varies with heliocentric distance r according to a power law nr ∝ r−ν. From Helios observations an exponent v = 1.3 is derived for the distance interval from 0.08 A.U. to 1 A.U. (Link et al. 1976). Outside the earth's orbit the Pioneer 10 and 11 results suggest a higher exponent v = 1.5 for the distance interval from 1 A.U. to 3.3. A.U. (Hanner et al., 1976). Giese and Grün (1976) showed that the results from zodiacal light observations are compatible with the micrometeoroid fluxes derived from in situ measurements and lunar crater statistics. They found that micrometeoroids in the size range from 10 μm to 100 μm radii (corresponding roughly to 10−8g to 10−5g) contribute most to the zodiacal light brightness.The orbital distribution of large interplanetary particles (10−6 g < m < 10−3g) is known from meteor observations. Sekanina and Southworth (1975) reported average orbital elements of these particles: ā ∼ 1.25 A.U., ē ∼ 0.4 and ī ∼ 20°. Orbital information on micrometeoroids (m < 10−8g) is obtained from in situ detectors on board the Pioneer 8 and 9 and Helios 1 spaceprobes and the HEOS-2 satellite. Characteristics of the different micrometeoroid experiments are given in Table 1. There is almost no time overlap in the data taking intervals of the experiments. Therefore one has to assume that there are no time variations of the meteoroid flux on the time scale of 1 to 10 years if one compares the results from the different experiments. This assumption may be violated for the smallest of the observed particles (m < 10−13g) due to strong electromagnetic interaction of these particles with the interplanetary magnetic field (Morfill and Grün 1979).

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 Clues in Zodiacal Light Observations for a Dust Ring Along the Earth's Orbit

1996 ◽  
Vol 150 ◽  
pp. 329-332
Author(s):  
J.B. Renard ◽  
R Dumont ◽  
A.C. Levasseur-Regourd ◽  
E. Hadamcik
Keyword(s):  
Numerical Simulations ◽  
Heliocentric Distance ◽  
Interplanetary Dust ◽  
The Sun ◽  
Zodiacal Light ◽  
Space Density ◽  
Infrared Observations ◽  
The Earth ◽  
Dust Ring

AbstractThe ability of the Earth to trap interplanetary grains into a dust ring lying along the terrestrial orbit was shown by numerical simulations and confirmed by infrared observations (IRAS, COBE). Such a ring could have its signature on the elongation dependence of the zodiacal brightness along the ecliptic, especially near 90° of the Sun. Indeed, the elongation dependence observed at Tenerife by Dumont and Sanchez (1975) shows that the space density of interplanetary dust slightly increases with increasing heliocentric distance, within the 2 or 3 hundredths of AU approaching Earth's orbit.

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