Collisional Evolution of the Edgeworth-Kuiper Belt: Implications for the Origin and Evolution of Small Body Populations

2002 ◽  
Vol 12 ◽  
pp. 219-222 ◽  
Author(s):  
Donald R. Davis ◽  
Paolo Farinella
Keyword(s):  
Size Distribution ◽  
Significant Role ◽  
Small Body ◽  
Kuiper Belt ◽  
Origin And Evolution ◽  
Short Period ◽  
Major Process ◽  
Collisional Evolution

AbstractCollisions have been a major process that shaped the Kuiper Belt that we see today. Collisional grinding likely played a significant role in removing mass from the trans-neptunian region and collisions are a mechanism for injecting fragments into resonances to start their journey to become short period comets. The Kuiper Belt preserves the accretional size distribution in bodies ≳ 100 km while the size distribution of smaller bodies is the result of collisional evolution. Observational confirmation of the transition size between these different regimes will constrain our understanding of the origin and evolution of the Kuiper Belt.

scholarly journals Impactor Flux on the Pluto-Charon System

2009 ◽  
Vol 5 (S263) ◽  
pp. 98-101 ◽  
Author(s):  
Gonzalo C. de Elía ◽  
Romina P. Di Sisto ◽  
Adrián Brunini
Keyword(s):  
Size Distribution ◽  
Kuiper Belt ◽  
Primary Source ◽  
Mean Motion ◽  
Stability And Instability ◽  
The Stability ◽  
Mean Motion Resonance ◽  
Collisional Evolution

AbstractIn this work, we study the impactor flux on Pluto and Charon due to the collisional evolution of Plutinos.To do this, we develop a statistical code that includes catastrophic collisions and cratering events, and takes into account the stability and instability zones of the 3:2 mean motion resonance with Neptune. Our results suggest that if 1 Pluto-sized object is in this resonance, the flux of D = 2 km Plutinos on Pluto is ~4–24 percent of the flux of D = 2 km Kuiper Belt projectiles on Pluto. However, with 5 Pluto-sized objects in the resonance, the contribution of the Plutino population to the impactor flux on Pluto may be comparable to that of the Kuiper Belt. As for Charon, if 1 Pluto-sized object is in the 3:2 resonance, the flux of D = 2 km Plutinos is ~10–63 percent of the flux of D = 2 km impactors coming from the Kuiper Belt. However, with 5 Pluto-sized objects, the Plutino population may be a primary source of the impactor flux on Charon. We conclude that it is necessary to specify the Plutino size distribution and the number of Pluto-sized objects in the 3:2 Neptune resonance in order to determine if the Plutino population is a primary source of impactors on the Pluto-Charon system.

scholarly journals Future Small Body Exploration after the Investigation of Asteroid Itokawa by Remote Sensing and Returned Sample Analyses

2012 ◽  
Vol 10 (H16) ◽  
pp. 152-152
Author(s):  
Hajime Yano
Keyword(s):  
Remote Sensing ◽  
Attitude Control ◽  
Small Body ◽  
Kuiper Belt ◽  
Cometary Nucleus ◽  
Ion Source ◽  
Communication Link ◽  
Sample Return ◽  
Origin And Evolution ◽  
Hayabusa 2

AbstractThis paper outlines current achievements of the Hayabusa mission and future small body missions with an emphasis on scientific prospects by both remote sensing in the vicinity of target objects and retuned sample analyses of them. First, the Hayabusa spacecraft aimed as technology demonstration for the worldfs first deep space round trip and sample return from an asteroid and it was launched via the M-V rocket in May of 2003. Soon after the touchdown on Asteroid Itokawa, a sub-km, S-type NEO in November 2005, the spacecraft lost its attitude control due to the leak of RCS propellant; the communication link was lost for 46 days. While the ion engine thrusters reached their lifetime by November of 2009 owing to either of an ion source or neutralizers at each engine, a challenging combination of the neutralizer-A with the ion source-B was devised to resume the spacecraftfs propulsion. This enabled the spacecraft to have returned to the Australian desert on the Earth in June 2010. The sample return capsule (SRC) was successfully recovered and returned to Japan for initial inspection of the Itokawa samples. After the announcement of initial sample analysis results, international announcement of sample distributions has started in the spring of 2012. Following up the original Hayabusa mission, JAXA has approved the Hayabusa-2 project in 2011, an asteroid sample return mission to 1999 JU3, a sub-km, C-type NEO aiming for 2014-5 launch, 2018-9 remote sensing including artificial impactor excavation and 2020 Earth return of both surface and sub-surface samples of the asteroid. C-type asteroid is thought to be abundant in organic matters and hydrated compound, so it has important clues to solve the origin and evolution of the life. NASAfs OSIRIS-Rex and ESAfs Marco Polo-R missions are also carbonaceous asteroid sample return missions in 2010fs-2020fs. Cometary nucleus or/and D-type asteroid sample returns like Hayabusa-Mk-II concept are natural progression of this type of the endeavor. JAXAfs solar power sail mission aims for eventual rendezvous with Jovian Trojan asteroids, reservoir of D/P-type asteroids as either leftovers of Jupiter system formation or the second generation intruders from the Kuiper belt regions.

The formation and evolution of the Solar System

2002 ◽  
Vol 10 (2) ◽  
pp. 171-184
Author(s):  
THÉRÈSE ENCRENAZ
Keyword(s):  
Solar System ◽  
Kuiper Belt ◽  
Giant Planets ◽  
The Sun ◽  
Silicate Material ◽  
Surface Information ◽  
Origin And Evolution ◽  
Short Period ◽  
Formation And Evolution ◽  
Main Components

Astronomers have built the main components of a scenario for the formation of the Solar System. Small planetary bodies accreted others by collisions within a rotating protoplanetary disk that formed at the same time as the Sun. While terrestrial planets near the warming Sun could accumulate only solid metallic and silicate material, the giant planets formed from ice and gas at lower temperatures. Each planet and satellite then followed its own specific evolution, depending upon the properties of its atmosphere and/or surface. Information about the origin and evolution of the Solar System is also provided by the comets, which can be considered as frozen fossils of the Solar System's early stages. On the borders of the outer Solar System, beyond the orbit of Neptune, the newly discovered Edgeworth–Kuiper belt is probably the reservoir where short-period comets are formed.

scholarly journals Rapid, large-scale species discovery in hyperdiverse taxa using 1D MinION sequencing

BMC Biology ◽  
2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Amrita Srivathsan ◽  
Emily Hartop ◽  
Jayanthi Puniamoorthy ◽  
Wan Ting Lee ◽  
Sujatha Narayanan Kutty ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Large Scale ◽  
Low Cost ◽  
Small Body ◽  
Small Subset ◽  
Similar Species ◽  
Large Species ◽  
Morphological Examination ◽  
Species Discovery ◽  
Short Period

Abstract Background More than 80% of all animal species remain unknown to science. Most of these species live in the tropics and belong to animal taxa that combine small body size with high specimen abundance and large species richness. For such clades, using morphology for species discovery is slow because large numbers of specimens must be sorted based on detailed microscopic investigations. Fortunately, species discovery could be greatly accelerated if DNA sequences could be used for sorting specimens to species. Morphological verification of such “molecular operational taxonomic units” (mOTUs) could then be based on dissection of a small subset of specimens. However, this approach requires cost-effective and low-tech DNA barcoding techniques because well-equipped, well-funded molecular laboratories are not readily available in many biodiverse countries. Results We here document how MinION sequencing can be used for large-scale species discovery in a specimen- and species-rich taxon like the hyperdiverse fly family Phoridae (Diptera). We sequenced 7059 specimens collected in a single Malaise trap in Kibale National Park, Uganda, over the short period of 8 weeks. We discovered > 650 species which exceeds the number of phorid species currently described for the entire Afrotropical region. The barcodes were obtained using an improved low-cost MinION pipeline that increased the barcoding capacity sevenfold from 500 to 3500 barcodes per flowcell. This was achieved by adopting 1D sequencing, resequencing weak amplicons on a used flowcell, and improving demultiplexing. Comparison with Illumina data revealed that the MinION barcodes were very accurate (99.99% accuracy, 0.46% Ns) and thus yielded very similar species units (match ratio 0.991). Morphological examination of 100 mOTUs also confirmed good congruence with morphology (93% of mOTUs; > 99% of specimens) and revealed that 90% of the putative species belong to the neglected, megadiverse genus Megaselia. We demonstrate for one Megaselia species how the molecular data can guide the description of a new species (Megaselia sepsioides sp. nov.). Conclusions We document that one field site in Africa can be home to an estimated 1000 species of phorids and speculate that the Afrotropical diversity could exceed 200,000 species. We furthermore conclude that low-cost MinION sequencers are very suitable for reliable, rapid, and large-scale species discovery in hyperdiverse taxa. MinION sequencing could quickly reveal the extent of the unknown diversity and is especially suitable for biodiverse countries with limited access to capital-intensive sequencing facilities.

scholarly journals Comets (Existing Populations)

1994 ◽  
Vol 160 ◽  
pp. 77-94
Author(s):  
Ľ. Kresák
Keyword(s):  
Kuiper Belt ◽  
Dynamical Evolution ◽  
Oort Cloud ◽  
Survival Times ◽  
Evolutionary Time ◽  
Origin And Evolution ◽  
History Of ◽  
The Individual ◽  
Evolutionary Paths

The definition, population, extent, origin and evolution of the individual subsystems of comets and transitions between them are discussed, together with presentation of the relevant statistical data and their changes with time. The largest outer subsystems are unobservable, but their existence is documented by the necessity of progressive replenishment of the observable populations, with limited survival times. There is persuasive evidence for two different evolutionary paths, one from the Oort cloud and another from the Kuiper belt. While the extent and accuracy of the data available is increasing rapidly, the Jupiter family of comets is the only one for which the evolutionary time scales do not exceed by many orders of magnitude the history of astronomical observations. The individual comet populations differ from one another not only by the distribution of orbits, but also by the size distribution and aging rate of their members. Their dynamical evolution is coupled with disintegration processes, which make it questionable whether the present state can be interpreted as a long-term average.

scholarly journals Managing relationships through repetition

Pragmatics ◽  
2019 ◽  
Vol 29 (1) ◽  
pp. 57-82
Author(s):  
Saeko Machi
Keyword(s):  
Significant Role ◽  
The Other ◽  
Japanese Language ◽  
Talk Show ◽  
The Third ◽  
Short Period ◽  
Points Of View ◽  
Tv Talk Show ◽  
Dynamic Relationships

Abstract This study examines cross-speaker repetition in triadic conversations in the Japanese language. For the analysis, three sets of triadic conversations between close friends taken from a TV talk show are used. The results reveal that repetition in triadic conversations performs distinctive functions that are not observed in dyadic conversations: repetition often takes place between only two participants of the triad and allows the two to team up and strengthen their bond exclusively (teaming repetition), or even playfully tease the third participant (teasing repetition). Repetition is also shared between the three participants. In such cases, it allows the participants to create an instant bond by joking or referring to shared circumstances (immediate threefold repetition), or to gradually establish rapport by connecting their utterances and co-constructing a story (repetition relay). All these types of repetition express the participants’ points of view and contribute efficiently to their relationships that shift from moment to moment. The study further demonstrates cases in which one participant makes good use of various repetition types in a short period of time and efficiently allocates thoughts and feelings to the other two participants. The study concludes that repetition plays a significant role in Japanese conversation, helping speakers to converse smoothly and manage the dynamic relationships efficiently.

Broad oxygen tolerance in the nematode Caenorhabditis elegans

2000 ◽  
Vol 203 (16) ◽  
pp. 2467-2478 ◽  
Author(s):  
W.A. Van Voorhies ◽  
S. Ward
Keyword(s):  
Caenorhabditis Elegans ◽  
Metabolic Rate ◽  
Developmental Stages ◽  
Small Body ◽  
Metabolic Cost ◽  
Soil Nematode ◽  
Nematode Caenorhabditis Elegans ◽  
Oxygen Levels ◽  
C Elegans ◽  
Short Period

This study examined the effects of oxygen tensions ranging from 0 to 90 kPa on the metabolic rate (rate of carbon dioxide production), movement and survivorship of the free-living soil nematode Caenorhabditis elegans. C. elegans requires oxygen to develop and survive. However, it can maintain a normal metabolic rate at oxygen levels of 3.6 kPa and has near-normal metabolic rates at oxygen levels as low as 2 kPa. The ability to withstand low ambient oxygen levels appears to be a consequence of the small body size of C. elegans, which allows diffusion to supply oxygen readily to the cells without requiring any specialized respiratory or metabolic adaptations. Thus, the small size of this organism pre-adapts C. elegans to living in soil environments that commonly become hypoxic. Movement in C. elegans appears to have a relatively minor metabolic cost. Several developmental stages of C. elegans were able to withstand up to 24 h of anoxia without major mortality. Longer periods of anoxia significantly increased mortality, particularly for eggs. Remarkably, long-term exposure to 100 % oxygen had no effect on the metabolic rate of C. elegans, and populations were able to survive for a least 50 generations in 100 % (90 kPa) oxygen. Such hyperoxic conditions are fatal to most organisms within a short period.

Collisional Evolution of Small-Body Populations

Asteroids III ◽  
2002 ◽  
pp. 545-558
Author(s):  
Donald R. Davis ◽  
Daniel D. Durda ◽  
Francesco Marzari ◽  
Adriano Campo Bagatin ◽  
Ricardo Gil-Hutton
Keyword(s):  
Small Body ◽  
Collisional Evolution

scholarly journals Pyrene-based aggregation-induced emission luminogens (AIEgen): structure correlated with particle size distribution and mechanochromism

2019 ◽  
Vol 7 (23) ◽  
pp. 6932-6940 ◽  
Author(s):  
Xing Feng ◽  
Jun Zhang ◽  
Zhen Hu ◽  
Qingsong Wang ◽  
Md. Monarul Islam ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Significant Role ◽  
Emission Intensity ◽  
Morphological Changes ◽  
Nano Particle ◽  
Aggregation Induced Emission ◽  
Water Fraction ◽  
Particle Species

The morphology of pyrene-based AIEgens changes depending on the water fraction. The different size distribution and morphological changes of nano-particle species play a significant role in enhancing the emission intensity in the aggregated state.

scholarly journals Zodiacal exoplanets in time – X. The orbit and atmosphere of the young ‘neptune desert’-dwelling planet K2-100b

2020 ◽  
Vol 495 (1) ◽  
pp. 650-662 ◽  
Author(s):  
E Gaidos ◽  
T Hirano ◽  
A W Mann ◽  
D A Owens ◽  
T A Berger ◽  
...  
Keyword(s):  
Mass Loss ◽  
Spherically Symmetric ◽  
Orbital Eccentricity ◽  
Origin And Evolution ◽  
Atmospheric Escape ◽  
Hyades Cluster ◽  
Solar Composition ◽  
Short Period ◽  
Elevated Activity ◽  
Core Accretion

ABSTRACT We obtained high-resolution infrared spectroscopy and short-cadence photometry of the 600–800 Myr Praesepe star K2-100 during transits of its 1.67-d planet. This Neptune-size object, discovered by the NASA K2 mission, is an interloper in the ‘desert’ of planets with similar radii on short-period orbits. Our observations can be used to understand its origin and evolution by constraining the orbital eccentricity by transit fitting, measuring the spin-orbit obliquity by the Rossiter–McLaughlin effect, and detecting any extended, escaping the hydrogen–helium envelope with the 10 830 -Å line of neutral helium in the 2s3S triplet state. Transit photometry with 1-min cadence was obtained by the K2 satellite during Campaign 18 and transit spectra were obtained with the IRD spectrograph on the Subaru telescope. While the elevated activity of K2-100 prevented us from detecting the Rossiter–McLaughlin effect, the new photometry combined with revised stellar parameters allowed us to constrain the eccentricity to e < 0.15/0.28 with 90/99 per cent confidence. We modelled atmospheric escape as an isothermal, spherically symmetric Parker wind, with photochemistry driven by ultraviolet radiation, which we estimate by combining the observed spectrum of the active Sun with calibrations from observations of K2-100 and similar young stars in the nearby Hyades cluster. Our non-detection (<5.7 m Å) of a transit-associated He i line limits mass-loss of a solar-composition atmosphere through a T ≤ 10000 K wind to <0.3 M⊕ Gyr−1. Either K2-100b is an exceptional desert-dwelling planet, or its mass-loss is occurring at a lower rate over a longer interval, consistent with a core accretion-powered scenario for escape.

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