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 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 Dust Measurements in the Outer Solar System

1994 ◽  
Vol 160 ◽  
pp. 367-380
Author(s):  
Eberhard Grün
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Thermal Emission ◽  
Scattered Light ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Spatial Density ◽  
Outer Solar System ◽  
The Sun

In-situ measurements of micrometeoroids provide information on the spatial distribution of interplanetary dust and its dynamical properties. Pioneers 10 and 11, Galileo and Ulysses spaceprobes took measurements of interplanetary dust from 0.7 to 18 AU distance from the sun. Distinctly different populations of dust particles exist in the inner and outer solar system. In the inner solar system, out to about 3 AU, zodiacal dust particles are recognized by their scattered light, their thermal emission and by in-situ detection from spaceprobes. These particles orbit the sun on low inclination (i ≤ 30°) and moderate eccentricity (e ≤ 0.6) orbits. Their spatial density falls off with approximately the inverse of the solar distance. Dust particles on high inclination or even retrograde trajectories dominate the dust population outside about 3 AU. The dust detector on board the Ulysses spaceprobe identified interstellar dust sweeping through the outer solar system on hyperbolic trajectories. Within about 2 AU from Jupiter Ulysses discovered periodic streams of dust particles originating from within the jovian system.

scholarly journals The Contribution of Kuiper Belt Dust Grains to the Inner Solar System

1996 ◽  
Vol 150 ◽  
pp. 163-166
Author(s):  
Jer-Chyi Liou ◽  
Herbert A. Zook ◽  
Stanley F. Dermott
Keyword(s):  
Solar System ◽  
Interstellar Dust ◽  
Numerical Study ◽  
Kuiper Belt ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Dust Grains ◽  
Zodiacal Light ◽  
Interplanetary Dust Particles ◽  
The Earth

AbstractThe recent discovery of the so-called Kuiper belt objects has prompted the idea that these objects produce dust grains that may contribute significantly to the interplanetary dust population at 1 AU. We have completed a numerical study of the orbital evolution of dust grains, of diameters 1 to 9 μm, that originate in the region of the Kuiper belt. Our results show that about 80% of the grains are ejected from the Solar System by the giant planets while the remaining 20% of the grains evolve all the way to the Sun. Surprisingly, these dust grains have small orbital eccentricities and inclinations when they cross the orbit of the Earth. This makes them behave more like asteroidal than cometary-type dust particles. This also enhances their chances to be captured by the Earth and makes them a possible source of the collected interplanetary dust particles (IDPs); in particular, they represent a possible source that brings primitive/organic materials from the outer Solar System to the Earth.When collisions with interstellar dust grains are considered, however, Kuiper belt dust grains larger than about 9 μm appear likely to be collisionally shattered before they can evolve to the inner part of the Solar System. Therefore, Kuiper belt dust grains may not, as they are expected to be small, contribute significantly to the zodiacal light.

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 Physical Modeling of the Zodiacal Dust Cloud

2001 ◽  
Vol 204 ◽  
pp. 17-34 ◽  
Author(s):  
Leonid M. Ozernoy
Keyword(s):  
Solar System ◽  
Physical Modeling ◽  
Interstellar Dust ◽  
Extrasolar Planets ◽  
Dust Cloud ◽  
Interplanetary Dust ◽  
Asteroid Belt ◽  
Dust Particles ◽  
Resonant Structure ◽  
Zodiacal Light

This review is based on extensive work done in collaboration with N. Gorkavyi, J. Mather, and T. Taidakova, which aimed at physical modeling of the interplanetary dust (IPD) cloud in the Solar System, i.e., establishing a link between the observable characteristics of the zodiacal cloud and the dynamical and physical properties of the parent minor bodies. Our computational approach permits one to integrate the trajectories of hundreds of particles and to effectively store up to 1010–11 positions with modest computer resources, providing a high fidelity 3D distribution of the dust. Our numerical codes account for the major dynamical effects that govern the motion of IPD particles: Poynting-Robertson (P-R) drag and solar wind drag; solar radiation pressure; particle evaporation; gravitational scattering by the planets; and the influence of mean-motion resonances. The incorporation of secular resonances and collisions of dust particles (both mutual and with interstellar dust) is underway. We have demonstrated the efficacy of our codes by performing the following analyses: (i) simulation of the distribution of Centaurs (comets scattered in their journey from the Kuiper belt inward in the Solar System) and revealing the effects of the outer planets in producing ‘cometary belts’; (ii) detailed inspection of a rich resonant structure found in these belts, which predicts the existence of gaps similar to the Kirkwood gaps in the main asteroid belt; (iii) a preliminary 3-D physical model of the IPD cloud, which includes three dust components – asteroidal, cometary, and kuiperoidal – and is consistent with the available data of Pioneer and Voyager dust detectors; (iv) modeling of the IPD cloud, which provides a zodiacal light distribution in accord, to the order of 1%, with a subset of the COBE/DIRBE observations; and (v) showing that the resonant structure in dusty circumstellar disks of Vega and Epsilon Eridani is a signature of embedded extrasolar planets. Further improvements of our modeling and their importance for astronomy and cosmology are outlined.

scholarly journals Cometary dust in Antarctic micrometeorites

2012 ◽  
Vol 8 (S288) ◽  
pp. 123-129 ◽  
Author(s):  
Naoya Imae
Keyword(s):  
Interstellar Dust ◽  
Compositional Analysis ◽  
Interplanetary Dust ◽  
Coarse Grained ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Interstellar Gas ◽  
Cometary Nuclei ◽  
Fine Grained ◽  
Cometary Dust

AbstractCometary nuclei consist of aggregates of interstellar dust particles less than ~1 μm in diameter and can produce rocky dust particles as a result of the sublimation of ice as comets enter the inner solar system. Samples of fine-grained particles known as chondritic porous interplanetary dust particles (CP-IDPs), possibly from comets, have been collected from the Earth's stratosphere. Owing to their fine-grained texture, these particles were previously thought to be condensates formed directly from interstellar gas. However, coarse-grained chondrule-like objects have recently been observed in samples from comet 81P/Wild 2. The chondrule-like objects are chemically distinct from chondrules in meteoritic chondrites, possessing higher MnO contents (0.5 wt%) in olivine and low-Ca pyroxene. In this study, we analyzed AMM samples by secondary electron microscopy and backscattered electron images for textural observations and compositional analysis. We identified thirteen AMMs with characteristics similar to those of the 81P/Wild 2 samples, and believe that recognition of these similarities necessitates reassessment of the existing models of chondrule formation.

scholarly journals Comet fragmentation as a source of the zodiacal cloud

2021 ◽  
Author(s):  
Jessica Rigley ◽  
Mark Wyatt
Keyword(s):  
Solar System ◽  
Kinetic Model ◽  
Size Distribution ◽  
Thermal Emission ◽  
Kuiper Belt ◽  
Radial Profile ◽  
Interplanetary Dust ◽  
Zodiacal Light ◽  
Zodiacal Cloud ◽  
Dynamical Simulations

<p>Models of the thermal emission of the zodiacal cloud and sporadic meteoroids suggest that the dominant source of interplanetary dust is Jupiter-family comets (JFCs). However, comet sublimation is insufficient to sustain the quantity of dust presently in the inner solar system. It has therefore been suggested that spontaneous disruptions of JFCs may supply the zodiacal cloud.</p> <p>We present a model for the dust produced in comet fragmentations and its evolution, comparing with the present day zodiacal cloud. Using results from dynamical simulations we follow individual JFCs as they evolve and undergo recurrent splitting events. The dust produced by these events is followed with a kinetic model which takes into account the effects of collisional evolution, Poynting-Robertson drag, and radiation pressure. This allows us to model both the size distribution and radial profile of dust resulting from comet fragmentation. Our model suggests that JFC fragmentations can produce enough dust to sustain the zodiacal cloud. We also discuss the feasibility of comet fragmentation producing the spatial and size distribution of dust seen in the zodiacal cloud.</p> <p>By modelling individual comets we are also able to explore the variability of cometary input to the zodiacal cloud. Comets are drawn from a size distribution based on the Kuiper belt and fragment randomly. We show that large comets should be scattered into the inner solar system stochastically, leading to large variations in the historical brightness of the zodiacal light.</p>

scholarly journals Fine Resolution Brightness Distribution of the Visible Zodiacal Light

1991 ◽  
Vol 126 ◽  
pp. 183-186
Author(s):  
S. M. Kwon ◽  
S. S. Hong ◽  
J. L. Weinberg ◽  
N. Y. Misconi
Keyword(s):  
Angular Resolution ◽  
Brightness Distribution ◽  
Time Dependent ◽  
Diffuse Light ◽  
Zodiacal Light ◽  
Sky Brightness ◽  
Night Sky ◽  
Fine Resolution ◽  
Night Sky Brightness ◽  
East West

AbstractApplying time-dependent corrections of the atmospheric diffuse light to the observed night sky brightness, we have determined brightness of the zodiacal light over the region 40° ≤λ − λ⊙ ≤;320ΰand − 20°≤β≤20ΰ. The resulting map of equal brightness contours has an angular resolution of two degrees, and exhibits east-west and north-south asymmetries.

scholarly journals Dynamic Populations of Dust in Interplanetary Space

1996 ◽  
Vol 150 ◽  
pp. 3-14 ◽  
Author(s):  
E. Grün ◽  
P. Staubach
Keyword(s):  
Radiation Pressure ◽  
Small Particle ◽  
Interstellar Dust ◽  
Interplanetary Space ◽  
Interplanetary Dust ◽  
Infrared Emission ◽  
Zodiacal Light ◽  
Electromagnetic Interactions ◽  
Keplerian Orbits ◽  
Halo Population

AbstractInformation on the dynamics of interplanetary dust is obtained by observations of radio-meteors, zodiacal light, thermal infrared emission, and by measurements with in-situ detectors on board Earth satellites and deep spaceprobes. These methods are sensitive to different meteoroid sizes (mm- to sub-micron sized) and refer to different regions of space. Bigger particles (> 10-9 g) move on bound Keplerian orbits and are dynamically dominated by solar gravity, while the trajectories of particles smaller than 10-10 g are strongly influenced by radiation pressure and electromagnetic interactions. Modelling interplanetary dust is done by dividing the whole meteoritic complex into dynamically distinct populations. Divine's (1993) model identifies five dynamically different populations of interplanetary meteoroids: bigger particles are described by the “core”, and “asteroidal”-populations, intermediate sizes by the “halo”-population, and small particles are included in the “eccentric” and the “inclined”-populations. The intermediate and the small particle populations, in particular, have to be redefined for several reasons: new data are available which require the consideration of hyperbolic orbits and the inclusion of radiation pressure and electromagnetic forces. New small particle populations are interstellar dust and beta-meteoroids.

scholarly journals 21. Light of the Night Sky

1985 ◽  
Vol 19 (1) ◽  
pp. 227-234
Author(s):  
R. H. Giese ◽  
k Mattila ◽  
R. Dumont ◽  
Yu. I. Galperin ◽  
M. S. Hanner ◽  
...  
Keyword(s):  
Scattered Light ◽  
Statistical Significance ◽  
Dust Cloud ◽  
Interplanetary Dust ◽  
Sources Of Information ◽  
Zodiacal Light ◽  
Manned Spacecraft ◽  
Lunar Samples ◽  
Night Sky

The light of the night sky consists of atmospheric components (airglow, light scattered in the atmosphere) and – even in the case of spaceborne observations – of zodiacal, galactic and extragalactic light. Although all components are of similar importance, investigations on zodiacal light have profitted most by the space age since their object of research, the interplanetary dust cloud, became accessible to direct in-situ measurements. Lunar samples and measurements by micrometeoroid detectors provide individual and eventually detailed information on impact events, which however are limited in number and therefore restricted in statistical significance. Zodiacal light investigations involve scattered light of many particles in large volume elements and therefore provide global information about physical properties and spatial distribution of interplanetary dust grains, however just in terms of average values. Therefore both sources of information are complementary and a synthesis can only be achieved by synoptic interpretation of zodiacal light, micrometeoroid, and meteoroid investigations also including dynamical aspects. Measurements of zodiacal light (and emission) from rockets, manned or non manned spacecraft, and deep space probes gained drastically in importance compared to ground based observations. On the other hand investigations on airglow have become more and more a topic of geophysics Caeronomy). They remain relevant however to astronomy as far as photometric features are concerned. These general trends continued in the last triennium and have influenced the activities of our commission.

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