scholarly journals A bimodal distribution of haze in Pluto's atmosphere

2021 ◽  
Author(s):  
Siteng Fan ◽  
Peter Gao ◽  
Xi Zhang ◽  
Danica Adams ◽  
Nicholas Kutsop ◽  
...  
Keyword(s):  
Solar System ◽  
Size Distribution ◽  
Bimodal Distribution ◽  
Observational Evidence ◽  
Chemical Processes ◽  
Particle Sizes ◽  
New Horizons ◽  
Solar System Bodies ◽  
Haze Formation ◽  
Physical And Chemical

Abstract Pluto, Titan, and Triton make up a unique class of solar system bodies, with icy surfaces and chemically reducing atmospheres rich in organic photochemistry and haze formation. Hazes play important roles in these atmospheres, with physical and chemical processes highly dependent on particle sizes, but the haze size distribution in reducing atmospheres is currently poorly understood. Here we report observational evidence that Pluto's haze particles are bimodally distributed, which successfully reproduces the full phase scattering observations from New Horizons. This result suggests a dimensional transition in organic haze formation, and indicates that both oxidizing and reducing atmospheres can produce multi-modal hazes.

scholarly journals A bimodal distribution of haze in Pluto’s atmosphere

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Siteng Fan ◽  
Peter Gao ◽  
Xi Zhang ◽  
Danica J. Adams ◽  
Nicholas W. Kutsop ◽  
...  
Keyword(s):  
Shape Change ◽  
Bimodal Distribution ◽  
Observational Evidence ◽  
Chemical Processes ◽  
Particle Sizes ◽  
New Horizons ◽  
Solar System Bodies ◽  
Haze Formation ◽  
Physical And Chemical ◽  
Dynamical Origin

AbstractPluto, Titan, and Triton make up a unique class of solar system bodies, with icy surfaces and chemically reducing atmospheres rich in organic photochemistry and haze formation. Hazes play important roles in these atmospheres, with physical and chemical processes highly dependent on particle sizes, but the haze size distribution in reducing atmospheres is currently poorly understood. Here we report observational evidence that Pluto’s haze particles are bimodally distributed, which successfully reproduces the full phase scattering observations from New Horizons. Combined with previous simulations of Titan’s haze, this result suggests that haze particles in reducing atmospheres undergo rapid shape change near pressure levels ~0.5 Pa and favors a photochemical rather than a dynamical origin for the formation of Titan’s detached haze. It also demonstrates that both oxidizing and reducing atmospheres can produce multi-modal hazes, and encourages reanalysis of observations of hazes on Titan and Triton.

SIZE DISTRIBUTION AND SOLUBILITY OF 15 ELEMENTS IN ATMOSPHERIC AEROSOLS

1996 ◽  
Vol 06 (01n02) ◽  
pp. 299-310 ◽  
Author(s):  
M. KASAHARA ◽  
J.H. PARK ◽  
S. CHATANI
Keyword(s):  
Size Distribution ◽  
Atmospheric Aerosols ◽  
Size Range ◽  
Aerosol Particles ◽  
Bimodal Distribution ◽  
Coarse Fraction ◽  
Chemical Characteristics ◽  
Pixe Analysis ◽  
Mass Size ◽  
Physical And Chemical

To investigate the physical and chemical characteristics of atmospheric aerosols, aerosol particles were sampled with classifying into 13 size ranges between 0.01 and 30µm. Collected aerosol particles were separated into the soluble and insoluble components. The concentrations of 15 elements in both components were determined by a PIXE analysis using a 2.0MeV-proton beam. The mass size distribution of each element was illustrated in three types: mono-modal distribution having only one peak in the fine or coarse fraction and the bimodal distribution having one peak each in fine and coarse fractions. The mass mean diameter of 15 elements ranged between 0.62µm of S and 3.15µm of Fe. More than 85% of atmospheric aerosols consists of the lighter elements such as C, N, O, H and Al. The soluble component was dominant in the smaller size range and the insoluble component in the larger size range. Si, Ti and especially Fe existed in high insoluble state. Conversely, Ca, Zn, Br and especially S and Cl were dissolved in water.

scholarly journals The geology and geophysics of Kuiper Belt object (486958) Arrokoth

Science ◽  
2020 ◽  
Vol 367 (6481) ◽  
pp. eaay3999 ◽  
Author(s):  
J. R. Spencer ◽  
S. A. Stern ◽  
J. M. Moore ◽  
H. A. Weaver ◽  
K. N. Singer ◽  
...  
Keyword(s):  
Solar System ◽  
Smooth Surface ◽  
Kuiper Belt ◽  
Solar System Formation ◽  
Small Bodies ◽  
Kuiper Belt Object ◽  
New Horizons ◽  
Geological Features ◽  
Solar System Bodies ◽  
Contact Binary

The Cold Classical Kuiper Belt, a class of small bodies in undisturbed orbits beyond Neptune, is composed of primitive objects preserving information about Solar System formation. In January 2019, the New Horizons spacecraft flew past one of these objects, the 36-kilometer-long contact binary (486958) Arrokoth (provisional designation 2014 MU69). Images from the flyby show that Arrokoth has no detectable rings, and no satellites (larger than 180 meters in diameter) within a radius of 8000 kilometers. Arrokoth has a lightly cratered, smooth surface with complex geological features, unlike those on previously visited Solar System bodies. The density of impact craters indicates the surface dates from the formation of the Solar System. The two lobes of the contact binary have closely aligned poles and equators, constraining their accretion mechanism.

scholarly journals Ryugu: A brand-new planetary sample returned from a C-type asteroid

2021 ◽  
Author(s):  
Toru Yada ◽  
Masanao Abe ◽  
Tatsuaki Okada ◽  
Aiko Nakato ◽  
Kasumi Yogata ◽  
...  
Keyword(s):  
Solar System ◽  
Near Infrared ◽  
Chemical Properties ◽  
Building Blocks ◽  
Bulk Sample ◽  
Near Infrared Reflectance ◽  
Origin And Evolution ◽  
Thermal Measurements ◽  
Solar System Bodies ◽  
Physical And Chemical

Abstract C-type asteroids are considered to be primitive small Solar-System bodies enriched in water and organics, providing clues for understanding the origin and evolution of the Solar System and the building blocks of life. C-type asteroid 162173 Ryugu has been characterized by remote sensing and on-asteroid measurements with Hayabusa2, but further studies are expected by direct analyses of returned samples. Here we describe the bulk sample mainly consisting of rugged and smooth particles of millimeter to submillimeter size, preserving physical and chemical properties as they were on the asteroid. The particle size distribution is found steeper than that of surface boulders11. Estimated grain densities of the samples have a peak around 1350 kg m-3, which is lower than that of meteorites suggests a high micro-porosity down to millimeter-scale, as estimated at centimeter-scale by thermal measurements. The extremely dark optical to near-infrared reflectance and the spectral profile with weak absorptions at 2.7 and 3.4 microns implying carbonaceous composition with indigenous aqueous alteration, respectively, match the global average of Ryugu, confirming the sample’s representativeness. Together with the absence of chondrule and Ca-Al-rich inclusion of larger than sub-mm, these features indicate Ryugu is most similar to CI chondrites but with darker, more porous and fragile characteristics.

A re-assessment of the Kuiper belt size distribution for sub-kilometer objects

2020 ◽  
Author(s):  
Alessandro Morbidelli ◽  
David Nesvorny ◽  
William Bottke ◽  
Simone Marchi
Keyword(s):  
Solar System ◽  
Size Distribution ◽  
Production Function ◽  
Power Law ◽  
Kuiper Belt ◽  
Spatial Density ◽  
Early Solar System ◽  
Size Frequency Distribution ◽  
New Horizons ◽  
The Impact

<p>In this work we combine several constraints provided by the crater records on Arrokoth and the worlds of the Pluto system to compute the size-frequency distribution (SFD) of the crater production function for craters with diameter D≤ 10km. For this purpose, we use a Kuiper belt objects (KBO) population model calibrated on telescopic surveys, that describes also the evolution of the KBO population during the early Solar System. We further calibrate this model using the crater record on Pluto, Charon and Nix.  Using this model, we compute the impact probability of bodies with diameter d>2km on Arrokoth, integrated over the age of the Solar System, that we compare with the corresponding impact probability on Charon. Our result, together with the observed density of sub-km craters on Arrokoth's imaged surface, constrains the power law slope of the crater production function. Other constraints come from the absence of craters with 1<D<7km on Arrokoth, the existence of a single crater with D>7km and the relationship between the spatial density of sub-km craters on Arrokoth and of D ~ 20km craters on Charon. Together, these data suggest the crater production function on these worlds has a cumulative power law slope of -1.5<q<-1.2. Converted into a projectile SFD slope, we find -1.2<q<sub>KBO</sub><-1.0. These values are close to the cumulative slope of main belt asteroids in the 0.2-2km range, a population in collisional equilibrium (Bottke et al. 2020). For KBOs, however, this slope appears to extend down to objects a few tens of meters in diameter, as inferred from sub-km craters on Arrokoth. From the measurement of the dust density in the Kuiper belt made by the New Horizons mission, we predict that the SFD of the KBOs become steep again below approximately 30m. All these considerations strongly indicate that the size distribution of the KBO population is in collisional equilibrium.</p>

The Mars-94 and Mars-96 missions

1994 ◽  
Vol 349 (1690) ◽  
pp. 295-307 ◽  
Keyword(s):  
Solar System ◽  
Short Description ◽  
Chemical Processes ◽  
Scientific Instruments ◽  
Martian Surface ◽  
Surface Layers ◽  
The Past ◽  
Wide Range ◽  
Physical And Chemical

The main goal of Solar System studies in Russia for the next 10-15 years is Mars and the Mars-94 project is the first stage of this long-term space programme. In October 1994 it is planned to launch a spacecraft with the following components onboard: an orbiter, two small autonomous stations to be landed on the surface of Mars and two penetrators to analyse the underlying surface layers. The main scientific objectives of this mission are to investigate the evolution and contemporary physics of Mars, and to make, using various methods, a wide range of comprehensive studies of those physical and chemical processes which took place in the past and which continue there now. The payload of the Mars-94 orbiter includes 23 scientific instruments to study the Martian surface, the inner structure of the planet, its atmosphere, and its plasma envelope, as well as instruments for astrophysical studies. The next stage of the programme is a mission to Mars in 1996. At present the Mars-96 project includes a spacecraft with an orbiter, a Martian rover, a balloon, penetrators and small stations. A short description of the scenario, payload, and scientific objectives of these missions is presented in this paper.

scholarly journals Searching for water ice in the coma of interstellar object 2I/Borisov

2020 ◽  
Vol 634 ◽  
pp. L6 ◽  
Author(s):  
Bin Yang ◽  
Michael S. P. Kelley ◽  
Karen J. Meech ◽  
Jacqueline V. Keane ◽  
Silvia Protopapa ◽  
...  
Keyword(s):  
Solar System ◽  
Cross Section ◽  
Near Infrared ◽  
Chemical Processes ◽  
Spectral Slope ◽  
Water Ice ◽  
Extrasolar Systems ◽  
Physical And Chemical ◽  
Absorption Features ◽  
Rare Opportunity

Aims. Interstellar objects passing through our Solar System offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems. The main objective of our study is to search for diagnostic absorption features of water ice in the near-infrared (NIR) spectrum of the second interstellar object 2I/2019 Q4 (Borisov) and compare its ice features to those of the Solar System icy objects. Methods. We observed 2I in the NIR on three separate occasions. The first observation was made on 2019 September 19 UT using the SpeX spectrograph at the 3m IRTF and again on September 24 UT with the GNIRS spectrograph at the 8m GEMINI telescope; the last observation was made on October 09 UT with IRTF. Results. The spectra obtained from all three nights appear featureless. No absorption features associated with water ice are detected. Spectral modeling suggests that water grains, if present, comprise no more than 10% of the coma cross section. The comet consistently exhibits a red D-type like spectrum with a spectral slope of about 6% per 1000 Å, which is similar to that of 1I/’Oumuamua and is comparable to Solar System comets.

The Feasibility Study of Laser Particle Size Analyzer for Thick Pastes

2013 ◽  
Vol 372 ◽  
pp. 428-432
Author(s):  
Shuang Yu Zhang ◽  
Fu Yan Lv ◽  
Zheng Meng Xia ◽  
Na Li ◽  
Miao Wu
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Traditional Method ◽  
Particle Sizes ◽  
Laser Particle Size Analyzer ◽  
Upper Limit ◽  
Particle Size Analyzer ◽  
Coal Slime ◽  
Physical And Chemical

The particle size distribution determines the physical and chemical characteristics of the particle swarm, and then affects rheological properties and transportation resistance characteristics of the thick pastes . Therefore we should find a method to appropriately describe the particle size distribution of thick pastes. Take coal slime to represent, we contrast laser particle size analyzer test with traditional sieving test to find whether the laser particle size analyzer applies to thick pastes or not. The test shows that the laser particle size analyzer which is suitable for the thick pastes to measure their particle sizes. Although its results cant match with the traditional method perfectly, the upper limit particle size can be used as comparison parameter of both methods. In future, the particle size distribution can be directly used, and there is no need to translate it into the sieving particle size distribution.

scholarly journals Comet composition and Lab

2015 ◽  
Vol 11 (A29A) ◽  
pp. 227-227
Author(s):  
Dominique Bockelée-Morvan
Keyword(s):  
Solar System ◽  
Small Worlds ◽  
Icy Satellites ◽  
Small Bodies ◽  
New Horizons ◽  
Dwarf Planets ◽  
Cassini Mission ◽  
Solar System Bodies ◽  
Geochemical Analyses ◽  
Comet 67P

The XXIX IAU General Assembly took place during the golden year of the exploration of small solar system bodies. With the Rosetta ESA mission around comet 67P, NASA Dawn and New Horizons missions nearby dwarf planets Ceres and Pluto, respectively, and the NASA/Cassini mission in Saturn neighborhood, year 2015 marked an important step towards further understanding of small solar system bodies. On August 11-13, Focus meeting 9 "Highlights in the exploration of small worlds" gathered scientists of all over the world to present and discuss the spectacular results obtained from these missions, as well as recent achievements obtained from past missions, comprehensive spectroscopic surveys from space (e.g., Herschel, NEOWISE, Gaia), ground-based observations, and geochemical analyses. This meeting was also the opportunity to discuss the state of our understanding of the nature of the various populations of small bodies in the Solar System, including icy satellites, in a cosmo-chemistry perspective.

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