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in this study, heavy metal pollution in batlama stream flowing into the black sea from giresun (turkiye) province and the toxicity induced by this pollution were investigated by allium test. heavy metal concentrations in stream water were analyzed by using icp-ms. germination percentage, weight gain, root length, micro... | detection of heavy metal contamination in batlama stream (turkiye) and the potential toxicity profile |
this paper will constrain the possible sources and processes for the formation of recently observed h2o vapor plumes above the surface of the dwarf planet ceres. two hypotheses have been proposed: (1) cryovolcanism where the water source is the mantle and the heating source is still unknown or (2) comet-like sublimatio... | ceres: predictions for near-surface water ice stability and implications for plume generating processes |
this paper presents a new approach to analysing the brightness change of a jupiter family comet. we assume that the coma contains particles composed of water ice, carbonaceous, and silicate dust. different sizes of dust particles were taken into account following the adopted size distribution. from an analysis of moder... | the influence of the size of ice-dust particles on the amplitude of the change in the brightness of a comet caused by an outburst |
modelling the evolution of comets is a complex task aiming at providing constraints on physical processes and internal properties that are inaccessible to observations, although they could potentially bring key elements to our understanding of the origins of these primitive objects. this field has made a tremendous ste... | modelling the evolution of a comet subsurface: implications for 67p/churyumov-gerasimenko |
our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the khonsu region on the comet 67p/churyumov-gerasimenko. despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. it is noticeable that the smooth areas in khon... | spectrophotometry of the khonsu region on the comet 67p/churyumov-gerasimenko using osiris instrument images |
multi‑walled carbon nanotubes (mwcnts) have many applications in industry and used as additives in polymers, catalysts, anodes in lithium‑battery and drug delivery. there is little information about mwcnts' (210 nm) genotoxic potential on juvenile freshwater fish channa punctatus. therefore, in this study, we have dete... | assessment of dna damage and oxidative stress in juvenile channa punctatus (bloch) after exposure to multi‑walled carbon nanotubes |
we investigate the existence of ion-acoustic shock waves in a five component cometary plasma consisting of positively and negatively charged oxygen ions, kappa described hydrogen ions, hot solar electrons, and slightly colder cometary electrons. the kdvb equation has been derived for the system, and its solution plotte... | korteweg-devries-burgers (kdvb) equation in a five component cometary plasma with kappa described electrons and ions |
the optical, spectroscopic, and infrared remote imaging system (osiris), the scientific imaging system onboard the rosetta mission, has been acquiring images of the nucleus of the comet 67p/churyumov-gerasimenko since 2014 august with a resolution which allows a detailed analysis of its surface. indeed, data reveal a c... | geologic mapping of the comet 67p/churyumov-gerasimenko's northern hemisphere |
the comet physics laboratory (cophylab) is an international research program to study the physical properties of cometary analog materials under simulated space conditions. the project is dedicated to studying, with the help of multiple instruments and the different expertise and background from the different partners,... | the cophylab comet-simulation chamber |
carbon, hydrogen, nitrogen, oxygen, and sulfur are the main elements involved in the solid-phase chemistry of various astrophysical environments. among these elements, sulfur chemistry is probably the least well understood. we investigated whether sulfur ion bombardment within simple astrophysical ice analogs (originat... | organosulfur compounds formed by sulfur ion bombardment of astrophysical ice analogs: implications for moons, comets, and kuiper belt objects |
the young (50-400 myr) a3v star β leo is a primary target to study the formation history and evolution of extrasolar planetary systems as one of the few stars with known hot (∼1600 k), warm (∼600 k), and cold (∼120 k) dust belt components. in this paper, we present deep mid-infrared measurements of the warm dust bright... | the hosts survey: evidence for an extended dust disk and constraints on the presence of giant planets in the habitable zone of β leo |
a detailed study is made of celestial observations recorded in east asian and european history around a.d. 774-5 and 993-4. these include reports of supernovae, comets, sunspots and aurorae. the aim is to attempt to provide astronomical evidence in support of the measured 14c increases in tree rings at these dates. how... | astronomical evidence relating to the observed 14c increases in a.d. 774-5 and 993-4 as determined from tree rings |
one of the biggest surprises of the rosetta mission was the detection of o2 in the coma of 67p/churyumov-gerasimenko in remarkably high abundances. the measured levels of o2 in the coma are generally assumed to reflect the overall abundance and chemical origin of cometary o2 in the nucleus. along with its strong associ... | dual storage and release of molecular oxygen in comet 67p/churyumov-gerasimenko |
comet interceptor (comet-i) was selected in june 2019 as the first esa f-class mission. in 2029+, comet-i will hitch a ride to a sun-earth l2 quasi-halo orbit, as a co-passenger of esa's m4 ariel mission. it will then remain idle at the l2 point until the right departure conditions are met to intercept a yet-to-be-disc... | esa f-class comet interceptor: trajectory design to intercept a yet-to-be-discovered comet |
we report observations of the reactivations of the main-belt comets (mbcs) 238p/read and 288p/(300163) 2006 vw139 that also track the evolution of each object’s activity over several months in 2016 and 2017. we additionally identify and analyze archival sdss data showing 288p to have been active in 2000, meaning that b... | the 2016 reactivations of the main-belt comets 238p/read and 288p/(300163) 2006 vw139 |
the paper presents a new approach to determining the change in the brightness of a comet during an outburst. it was investigated how the porosity of the dust particle translates into an increase in comet brightness during an outburst. it has been shown that the greater the porosity of a given particle, the greater the ... | the influence of the porosity of dust particles on the amplitude of the change in the brightness of a comet |
bisphenol a (bpa), an infamous xenoestrogen, can cause the inimical environmental and health implications via generation of extremely reactive oxygen species (ros) and/or by mimicking the endocrine activity. the intention of this study was to understand the concentration range of bpa between 0.02-200 μg ml-1 that may i... | exploration of the ameliorative effect of dietary polyphenol on bisphenol-a prompted dna damage by in vitro and in silico approaches |
there are many discrepancies among the results of studies on the genotoxicity of lead. the aim of the study was to explore lead-induced dna damage, including oxidative damage, in relation to oxidative stress intensity parameters and the antioxidant defense system in human leukocytes. the study population consisted of 1... | oxidative dna damage and oxidative stress in lead-exposed workers |
context. we investigate the dust coma within the hill sphere of comet 67p/churyumov-gerasimenko.aims: we aim to determine osculating orbital elements for individual distinguishable but unresolved slow-moving grains in the vicinity of the nucleus. in addition, we perform photometry and constrain grain sizes.methods: we ... | orbital elements of the material surrounding comet 67p/churyumov-gerasimenko |
non-thermal radiation has been predicted within bow shocks around runaway stars by recent theoretical works. we present x-ray observations toward the runaway stars ζ oph by chandra and suzaku and of bd+43°3654 by xmm-newton to search for the presence of non-thermal x-ray emission. we found no evidence of non-thermal em... | x-ray observations of bow shocks around runaway o stars. the case of ζ oph and bd+43°3654 |
multiple outbursts of a jupiter-family comet (jfc), 15p/finlay, occurred from late 2014 to early 2015. we conducted an observation of the comet after the first outburst and subsequently witnessed another outburst on 2015 january 15.6-15.7. the gas, consisting mostly of c2 and cn, and dust particles expanded at speeds o... | 2014-2015 multiple outbursts of 15p/finlay |
in the era of "big data" and with the advent of web 2.0 technologies, esasky (http://sky.esa.int) aims at providing a modern and visual way to access astronomical science-ready data products and metadata. the main goal of the application is to simplify the interaction between the scientific community and the ever-growi... | esasky: a science-driven discovery portal for space-based astronomy missions |
the properties of dust inertial alfvén waves (diaws) in a dusty plasma with the effects of polarization force are investigated. first, the dispersion equation is obtained from the fluid equations by considering the polarization force. then, the energy balance equation is deduced by applying the sagdeev pseudopotential ... | inertial alfvén waves with polarization force in a dusty plasma |
outbursts and variations of brightness are well known manifestations of the physical activity of the comets. most cometary outbursts are recorded not very far from the sun, where sublimation of water ice plays a major role in the activity of this celestial bodies. however, comets sometimes show physical activity far fr... | a new simple model of comets-like activity of centaurs |
in the present article, we propose a new method of mass estimation which is ejected from a nucleus of a comet during its outburst of brightness. the phenomena of cometary outburst are often reported for both periodic and parabolic comets. the outburst of a comet brightness is a sudden increase in its brightness greater... | a new method for determining the mass ejected during the cometary outburst - application to the jupiter-family comets |
context. the issue of the long term dynamics of jupiter family comets (jfcs) involves uncertain assumptions about the physical evolution and lifetimes of these comets. contrary to what is often assumed, real effects of secular dynamics cannot be excluded and therefore merit investigation.aims: we use a random sample of... | secular orbital evolution of jupiter family comets |
this paper describes in detail hydroplastic structures, which are 'odd' kinematic indicators in the basal part of the eocene middle rus formation. such structures were previously ignored or falsely interpreted. these hydroplastic structures are found in the massive limestone exposures on the king fahd university of pet... | rus detachment in dammam dome, eastern saudi arabia: a new soft-sediment structure as a 'sensitive stress sensor' for the zagros collision |
it has been suggested that the comet-like activity of main-belt comets (mbcs) is due to the sublimation of sub-surface water-ice that is exposed when these objects are impacted by meter-sized bodies. we recently examined this scenario and showed that such impacts can, in fact, excavate ice and present a plausible mecha... | triggering the activation of main-belt comets: the effect of porosity |
we use n-body/hydrodynamical simulations to interpret the newly discovered bullet-cluster-like merging cluster zwcl 0008.8+5215 (zwcl008 hereafter), where a dramatic collision is apparent from multiwavelength observations. we have been able to find a self-consistent solution for the radio, x-ray, and lensing phenomena ... | multi-phenomena modeling of the new bullet-like cluster zwcl 008.8+52 using n-body/hydrodynamical simulations |
the water production rate of a comet is one of the fundamental parameters necessary to understand cometary activity when a comet approaches the sun within 2.5 au, because water is the most abundant icy material in the cometary nucleus. wide-field imaging observations of the hydrogen lyα emission in comet 67p/churyumov-... | imaging observations of the hydrogen coma of comet 67p/churyumov-gerasimenko in 2015 september by the procyon/laica |
as the solar system moves through the interstellar medium, the solar wind is deflected forming the heliosphere. the standard picture of the heliosphere is a comet-shape like structure with the tail extending for 1000s of astronomical units. this standard picture stems from a view where magnetic forces are negligible an... | magnetized jets driven by the sun: the structure of the heliosphere revisited—updates |
the disruption of an icy moon in a collision with an interloping comet a few hundred million years ago is a simple way to create saturn's rings. a ring parent moon with a mass comparable to mimas could be trapped in mean motion resonance with enceladus and dione in an orbit near the current outer edge of the rings just... | a recent origin for saturn's rings from the collisional disruption of an icy moon |
based on the high abundance of fine-grained material and its dark appearance, nwa 11024 was recognized as a cm chondrite, which is also confirmed by oxygen isotope measurements. but contrary to known cm chondrites, the typical phases indicating aqueous alteration (e.g., phyllosilicates, carbonates) are missing. using m... | northwest africa 11024—a heated and dehydrated unique carbonaceous (cm) chondrite |
we imaged comet 252p/2000 g1 (linear; hereafter 252p) with the hubble space telescope and both 252p and p/2016 ba14 (panstarrs; hereafter ba14) with the discovery channel telescope in 2016 march and april, surrounding its close encounter to earth. the r‧-band afρ of 252p in a 0.″2-radius aperture were 16.8 ± 0.3 and 57... | the unusual apparition of comet 252p/2000 g1 (linear) and comparison with comet p/2016 ba14 (panstarrs) |
small bodies in the solar system are conventionally classified into asteroids and comets. however, it is recently found that a small number of objects can exhibit properties of both asteroids and comets. some are more consistent with asteroids despite episodic ejections and are labeled as "active asteroids", while some... | meteor showers from active asteroids and dormant comets in near-earth space: a review |
we apply a principal component analysis (pca)-based pre-whitening method to the entire collection of main kepler mission long-cadence data for kic 8462852 spanning four years. this technique removes the correlated variations of instrumental origin in both the detected light curves and astrometry, resolving intrinsic ch... | photometric and astrometric vagaries of the enigma star kic 8462852 |
aims: 2p/encke is a short period comet that was discovered in 1786 and has been extensively observed and studied for more than 200 years. the taurid meteoroid stream has long been linked with 2p/encke owing to a good match of their orbital elements, even though the comet's activity is not strong enough to explain the n... | 2p/encke, the taurid complex neos and the maribo and sutter's mill meteorites |
this paper develops a unified linear theory of local cross-field plasma instabilities, such as the farley-buneman, electron thermal, and ion thermal instabilities, in collisional plasmas with fully or partially unmagnetized multi-species ions. collisional lasma instabilities in low-ionized, highly dissipative, weakly m... | unified fluid-model theory of $\\mathbf{e}\\times\\mathbf{b}$ instabilities in low-ionized collisional plasmas with arbitrarily magnetized multi-species ions |
the diffusion of gas through porous material is important to understand the physical processes underlying cometary activity. we study the diffusion of a rarefied gas (knudsen regime) through a packed bed of monodisperse spheres via experiments and numerical modelling, providing an absolute value of the diffusion coeffi... | simulation and experiment of gas diffusion in a granular bed |
the rosetta mission escorted comet 67p/churyumov-gerasimenko for approximately two years including the perihelion passage (1.24 au, 2015 august), allowing us to monitor the seasonal evolution of the water and carbon dioxide loss rates. here, we model 67p/churyumov-gerasimenko water and carbon dioxide production as meas... | comparison of a pebbles-based model with the observed evolution of the water and carbon dioxide outgassing of comet 67p/churyumov-gerasimenko |
context. high-mass stars form in much richer environments than those associated with isolated low-mass stars, and once they reach a certain mass, produce ionised (hii) regions. the formation of these pockets of ionised gas are unique to the formation of high-mass stars (m > 8 m⊙), and present an excellent opportunit... | the evolution of young hii regions. i. continuum emission and internal dynamics |
'oumuamua and borisov were the first two interstellar objects confirmed in the solar system. the upcoming commencement of the vera c. rubin observatory&'s legacy survey of space of time (lsst) will enhance greatly the discovery rate of interstellar objects. this raises the question, what can be learned from large-n... | observable signatures of the ejection speed of interstellar objects from their birth systems |
we investigate the chemical composition of the solar system's giant planets atmospheres using a physical formation model with chemistry. the model incorporate disc evolution, pebbles and gas accretion, type i and ii migration, simplified disc photoevaporation and solar system chemical measurements. we track the chemica... | a pebbles accretion model with chemistry and implications for the solar system |
we re-introduce a semiclassical methodology based on theories developed for the determination of broadening coefficients. we show that this simple and extremely fast methodology provides results that are in good agreement with results obtained using the more sophisticate mqct approach. this semiclassical methodology co... | new h2o-h2o collisional rate coefficients for cometary applications |
the discovery of the first interstellar comet 2i/borisov confirmed the astronomers' speculation that the passage through the solar system of relatively large objects (asteroids and comets) formed outside of it is a common occurrence. there may be many such objects, but their discovery is still a rare case. large profes... | discovery of the first interstellar comet and the spatial density of interstellar objects in the solar neighborhood |
we present a study of interstellar comet 2i/2019 q4 (borisov) using both preperihelion and postperihelion observations spanning late september 2019 through late january 2020. the intrinsic brightness of the comet was observed to continuously decline throughout the timespan, likely due to the decreasing effective scatte... | physical characterisation of interstellar comet 2i/2019 q4 (borisov) |
the near-sun comet c/2019 y4 (atlas) is the first member of a long-period comet group observed to disintegrate well before perihelion. here we present our investigation into this disintegration event using images obtained in a three-day hubble space telescope campaign. we identify two fragment clusters produced by the ... | disintegration of long-period comet c/2019 y4 (atlas). i. hubble space telescope observations |
planetary embryos are built through the collisional growth of 10-100 km-sized objects called planetesimals, a formerly large population of objects, of which asteroids, comets, and kuiper belt objects represent the leftovers from planet formation in our solar system. here, we follow the paradigm that turbulence created ... | high-resolution study of planetesimal formation by gravitational collapse of pebble clouds |
we review the properties of dust formed during classical nova eruptions and the very late thermal pulses (vltps) that occur during the later stages of post-asymptotic giant branch evolution of low-mass stars. in both cases, carbon and hydrocarbon dust is produced. novae may also produce silicate dust, contrary to the u... | pre-solar grains from novae and "born-again giants" |
we study the size frequency distribution of the blocks located in the deeply fractured, geologically active enceladus south polar terrain with the aim to suggest their formative mechanisms. through the cassini iss images, we identify ~17,000 blocks with sizes ranging from ~25 m to 366 m, and located at different distan... | blocks size frequency distribution in the enceladus tiger stripes area: implications on their formative processes |
cometary ice analogs: amorphous h2o ice can trap other molecules up to ∼30% by number, which are outgassed during ice crystallization (130 k to 150 k). beyond 160 k, crystalline ice sublimes with only a minor fraction (<1%) of other molecules with it. ice is a major component of astrophysical environments – from int... | thermal behavior of astrophysical amorphous molecular ices |
optical properties are required for the correct understanding and modelling of protoplanetary and debris discs. by assuming that comets are the most pristine bodies in the solar system, our goal is to derive optical constants of real protoplanetary material. we determine the complex index of refraction of the near-surf... | sub-mm/mm optical properties of real protoplanetary matter derived from rosetta/miro observations of comet 67p |
in this paper we presented the results of laboratory experiments dealing with the sliding of desiccated sand on the inclined surfaces of cometary analogs. the experiments were performed in a vacuum, using porous mixtures of water ice and quartz sand. the inclination angle of the surfaces of the samples was about 10 deg... | comets, sliding of surface dust ii |
planetesimals - asteroids and comets - are the building blocks of planets in protoplanetary discs and the source of dust, ice, and gas in debris discs. along with planets they comprise the left-over material after star formation that constitutes a planetary system. planets influence the dynamics of planetesimals, sculp... | stirred but not shaken: a multiwavelength view of hd 16743's debris disc |
i call attention to extraordinary features displayed by the genetically related long-period comet pair of c/1844 y1 (great comet) and c/2019 y4 (atlas). the issue addressed most extensively is the fragmentation and disintegration of the latter object, itself a thousands-of-years-old fragment. of the four fragments of c... | fragmentation and history of comet pair c/1844 y1 and c/2019 y4 |
i summarize and streamline the results of recent modeling of the orbital evolution and cascading fragmentation of the kreutz sungrazers. the model starts with aristotle's comet -- the progenitor whose nucleus is assumed to be a contact binary -- splitting near aphelion into the two lobes and concludes with the soho dwa... | kreutz sungrazers: summary of recent modeling and orbits of the soho objects |
volatiles, notably water, are key to the habitability of rocky planets. the presence of water in planetary material can be inferred from the atmospheric oxygen abundances of polluted white dwarfs, but this interpretation is often complex. we study the accretion process, and find that ices may sublimate and accrete befo... | asynchronous accretion can mimic diverse white dwarf pollutants ii: water content |
main belt comets (mbcs) exhibit sublimation-driven activity while occupying asteroid-like orbits in the main asteroid belt. mbcs and candidates show stronger clustering of their longitudes of perihelion around 15° than other objects from the outer main belt (omb). this potential property of mbcs could facilitate the di... | a targeted search for main belt comets |
planetesimals in the primordial disc may have experienced a collisional cascade. if so, the comet nuclei later placed in the kuiper belt, scattered disc, and oort cloud would primarily be fragments and collisional rubble piles from that cascade. however, the heating associated with the collisions cannot have been stron... | collisional heating of icy planetesimals - i. catastrophic collisions |
the omnipresence of dust particulates in space and astrophysical plasmas has been attracting numerous researchers to study the collective excitation and propagation dynamics of different eigen-mode structures in diversified astrocosmic circumstances for years. it includes planetary rings, interplanetary space, cometary... | acoustic waves in the jovian dusty magnetosphere: a brief review and meta-analysis |
kuiper-like belts of planetesimals orbiting stars other than the sun are most commonly detected from the thermal emission of small dust produced in collisions. emission from gas, most notably co, highlights the cometary nature of these planetesimals. here, we present models for the release of gas from comet-like bodies... | secondary gas in debris discs released following the decay of long-lived radioactive nuclides, catastrophic, or resurfacing collisions |
the claims of periodicity in impact cratering and biological extinction events are controversial. a newly revised record of dated impact craters has been analyzed for periodicity, and compared with the record of extinctions over the past 260 myr. a digital circular spectral analysis of 37 crater ages (ranging in age fr... | periodic impact cratering and extinction events over the last 260 million years |
we present a three-dimensional model of the evolution of the asteroid-cometary-planetary (acp) component of the solar system under the gravitational influence of jupiter. we demonstrate the origin of the kuiper belt of the sun, the oort cloud of the sun and jupiter, as well as the acp "spear," which becomes elongated w... | generation of unbound comets and planets by planetary systems |
context. several authors predicted an outburst of the draconid meteor shower in 2018, but with an uncertain level of activity.aims: optical meteor observations were used to derive the population and mass indices, flux, and radiant positions of draconid meteors.methods: we performed 90 min of multi-station observations ... | a new method for measuring the meteor mass index: application to the 2018 draconid meteor shower outburst |
while water and sulfuric acid droplets are the main component of stratospheric aerosols, measurements performed for about 30 years have shown that non-sulfate particles (nsps) are also present. such particles, released from the earth mainly through volcanic eruptions, pollution or biomass burning, or coming from space,... | origins and spatial distribution of non-pure sulfate particles (nsps) in the stratosphere detected by the balloon-borne light optical aerosols counter (loac) |
the chapter provides a comprehensive and up to date review of physical properties (structure, strength, porosity etc.) and chemical composition of small solar system bodies with sizes ranging from several micrometers to several meters. experts from different fields of research, using different methods, joined their eff... | physical and chemical properties of meteoroids |
ancient chinese, korean, and vietnamese observers left us records of celestial sightings, the so‑called "guest stars" dated up to ∼2500 years ago. their identification with modern observable targets could open interesting insights into the long‑term behavior of astronomical objects, as shown by the successful identific... | a new approach to generate a catalogue of potential historical novae |
we present measurements of comet 46p/wirtanen obtained by the neowise spacecraft in 2017 through 2019. we detected signal in excess of the dust in the 4.6 μm channel attributable to the presence of co, or more likely, co2 emission. the excess, when the comet was outbound at a heliocentric distance of 1.9 au, was consis... | neowise observed co and co2 production rates of 46p/wirtanen during the 2018-2019 apparition |
the lander philae of the rosetta mission landed on the surface of the comet 67 p/churyumov-gerasimenko on november 12, 2014. among the specific subsystems and instruments carried on philae, the sampling, drilling and distribution (sd2) subsystem had the role of providing in-situ operations devoted to soil drilling, sam... | planning and implementation of the on-comet operations of the instrument sd2 onboard the lander philae of rosetta mission |
this paper reviews the current knowledge on the composition of cometary dust (ice, minerals and organics) in order to constrain their origin and formation mechanisms. comets have been investigated by astronomical observations, space missions (giotto to rosetta), and by the analysis of cometary dust particles collected ... | variations in cometary dust composition from giotto to rosetta, clues to their formation mechanisms |
context. sulfur is an abundant element in the cosmos and it is thus an important contributor to astrochemistry in the interstellar medium and in the solar system. astronomical observations of the gas and of the solid phases in the dense interstellar/circumstellar regions have evidenced that sulfur is underabundant. the... | thermal and energetic processing of astrophysical ice analogues rich in so2 |
we searched for rotational lines of h12c14n in comet 46p/wirtanen, using the purple mountain observatory 13.7 m radio telescope. the j = 1-0 lines of hcn (3.4 mm wavelength) were unambiguously detected in 46p during the 2018 december 14-15 period, with a beam resolution of 62"2 and a velocity resolution of ∼0.21 km s-1... | observations of the hydrogen cyanide in comet 46p/wirtanen at a 3.4 mm wavelength |
the nucleus of the jupiter-family comet 67p/churyumov-gerasimenko was discovered to be bi-lobate in shape when the european space agency spacecraft rosetta first approached it in 2014 july. the bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on h... | a comparison between the two lobes of comet 67p/churyumov-gerasimenko based on d/h ratios in h2o measured with the rosetta/rosina dfms |
uncontrolled urbanization growth contributes to the pollution of aquatic environments. heavy metals released by domestic and industrial effluents can negatively affect aquatic organisms. this study aimed to evaluate the effect of environmental pollutants, such as metals, on fish dna damage, in stretches of an urban str... | genotoxic effect of heavy metals on astyanax lacustris in an urban stream |
without a significant atmosphere or global magnetic field, the lunar surface is exposed to micrometeoroid bombardment, ultraviolet (uv) radiation, and the solar wind. micrometeoroid bombardment grinds the surface into a regolith comprised of dust grains ranging in size from 10 nm to 1 mm (grün et al., 2011). incident u... | the effect of asymmetric surface topography on dust dynamics on airless bodies |
the esa mission comet interceptor will target an oort or interstellar comet during its first approach to the sun. meanwhile, the vera rubin lsst survey will observe hundreds of active comets per month beyond 4 au from the sun, where water vapour pressure is expected to be too low to eject dust. we discuss observations ... | comets beyond 4 au: how pristine are oort nuclei? |
here, two of a range of possible models are explored that assume that: (i) two of the main chondritic components (chondrules and refractory inclusions) dominated the earth's building blocks, (ii) that their relative abundances differed from those of known chondrites, and (iii) that the elemental compositions of all com... | an exploration of whether earth can be built from chondritic components, not bulk chondrites |
asteroids show a variety of shapes, ranging from roundish to elongated to binary systems and 'contact binaries' like (25143) itokawa, the target of the hayabusa mission (jaxa). these bodies spend most of their time within a collisional system, the asteroid belt, where impact processes are relatively frequent. speculati... | gravitational re-accumulation as the origin of most contact binaries and other small body shapes |
cometary dust provides a unique window on dust growth mechanisms during the onset of planet formation. measurements by the rosetta spacecraft show that the dust in the coma of comet 67p/churyumov-gerasimenko has a granular structure at size scales from sub-μmup to several hundreds of μm, indicating hierarchical growth ... | the footprint of cometary dust analogues - i. laboratory experiments of low-velocity impacts and comparison with rosetta data |
using chemical and petrologic evidence and modeling, we deduce that two chondrule-like particles named iris and callie, from stardust cometary track c2052,12,74, formed in an environment very similar to that seen for type ii chondrules in meteorites. iris was heated near liquidus, equilibrated, and cooled at ≤100 °c h-... | constraints on the formation environment of two chondrule-like igneous particles from comet 81p/wild 2 |
this study explores the long-duration (0.8-2.3 ma), time-averaged micrometeorite flux (mass and size distribution) reaching earth, as recorded by the transantarctic mountains (tam) micrometeorite collection. we investigate a single sediment trap (tam65), performing an exhaustive recovery and characterization effort and... | the extraterrestrial dust flux: size distribution and mass contribution estimates inferred from the transantarctic mountains (tam) micrometeorite collection |
we examine the development of the active asteroid 311p/panstarrs (formerly, 2013 p5) in the period from 2013 september to 2014 february using high resolution images from the hubble space telescope. this multi-tailed object is characterized by a single, reddish nucleus of absolute magnitude h >= 18.98 ± 0.10, corresp... | episodic ejection from active asteroid 311p/panstarrs |
within the framework of the heterogeneous dust evolution model for interstellar solids (themis), this work explores the surface processes and chemistry relating to core/mantle interstellar and cometary grain structures and their influence on the nature of these fascinating particles. it appears that a realistic conside... | dust evolution, a global view: iii. core/mantle grains, organic nano-globules, comets and surface chemistry |
the branching ratios for the n(4s) + n(2d), n(4s) + n(2p), and n(2d) + n(2d) channels are measured for the photodissociation of {{{n}}}2({x}1{{{{σ }}}g}+;v\prime\prime =0,j\prime\prime ) in the vacuum ultraviolet (vuv) region of 100,808-122,159 cm-1 using the vuv-vuv pump-probe approach combined with velocity-map-imagi... | quantum-state dependence of product branching ratios in vacuum ultraviolet photodissociation of n2 |
the observed rate of water production of comet 67p/churyumov-gerasimenko near its perihelion can be approximated by a very steep power function of the heliocentric distance. widely used thermophysical models based on a static dust layer on top of the icy/refractory matrix are poorly consistent with these observations. ... | near-perihelion activity of comet 67p/churyumov-gerasimenko. a first attempt of non-static analysis |
the james webb space telescope (jwst), as the largest space-based astronomical observatory with near- and mid-infrared instrumentation, will elucidate many mysterious aspects of comets. we summarize four cometary science themes especially suited for this telescope and its instrumentation: the drivers of cometary activi... | cometary science with the james webb space telescope |
we provide a three-dimensional model of the inner layered structure of comet 67p based on the hypothesis of an extended layering independently wrapping each lobe. a large set of terrace orientations was collected on the latest shape model and then used as a proxy for the local orientation of the surfaces of discontinui... | a three-dimensional modelling of the layered structure of comet 67p/churyumov-gerasimenko |
staphylococcus aureus is historically regarded as a non-motile organism. more recently it has been shown that s. aureus can passively move across agar surfaces in a process called spreading. we re-analysed spreading motility using a modified assay and focused on observing the formation of dendrites: branching structure... | staphylococcus aureus forms spreading dendrites that have characteristics of active motility |
a catalogue of equatorial coordinates and magnitudes for 2162 asteroids and 11 comets was compiled based on the results of processing of digitized photographic observations of the northern sky performed in 1981-1985. the positions were compared with the jpl de431 ephemeris. the mean (o - c)αδ values for all positions o... | catalogue of asteroids from digitized photographic plates of the fon program |
debris discs are second-generation dusty discs thought to be devoid of gas. however, this idea has been challenged in the last years by gas detections in some systems. we compiled a database of 301 debris discs and collected high-resolution optical spectra for ∼77 per cent of them. from the analysis of these data we id... | debris discs with multiple absorption features in metallic lines: circumstellar or interstellar origin? |
on the nucleus of comet 67p/churyumov-gerasimenko numerous pits and depressions of different sizes are identified. in the present work the origin of depression hatmehit is investigated. we propose a mechanism that includes recession of the surface due to sub-dust sublimation together with formation of cavities. recessi... | comet 67p/churyumov-gerasimenko, possible origin of the depression hatmehit |
suprathermal electrons with energies of ∼70 ev and above are observed at 1 au as dispersionless halo electrons and magnetic field-aligned beams of strahls. for a long time, it has been thought that both populations originate only from the solar corona, and that the only active process impacting their properties in the ... | counterstreaming strahls and heat flux dropouts as possible signatures of local particle acceleration in the solar wind |
air pollution is one the main causes of dna damage in living organisms. continuous exposure to the complex mixture of gases of polluted atmospheres affects health in many ways. sentinel organisms are good biological models to assess the genotoxic damage caused by various chemicals such as atmospheric pollutants. in thi... | in situ biomonitoring of air quality in rural and urban environments of mexico valley through genotoxicity evaluated in wild plants |
the international rosetta mission was launched on 2nd march 2004 and after its ten year journey, arrived at its target destination of comet 67p/churyumov-gerasimenko, during 2014. following the january 2014 exit from a two and half year hibernation period, rosetta approached and arrived at the comet in august 2014. in ... | rosetta science operations in support of the philae mission |
we use a thermodynamic statistical model to evaluate how the composition of europa’s internal ocean may have been affected by clathrate hydrate formation. assuming an input of the observed o2 and co2 from the surface into a mildly acidic ocean (ph < 6), and considering the possibility of contributions by reduced (wi... | the role of clathrate formation in europa’s ocean composition |
over the past thirty years, spacecraft missions, earth-based radar experiments, and telescopic observations have revolutionized our knowledge of main belt asteroids, near-earth asteroids, and comet nuclei. as a result of this effort, we now possess high resolution shape models and well-constrained spin rates, pole orie... | small body shapes and spins reveal a prevailing state of maximum topographic stability |
the lunar dust experiment (ldex), aboard nasa's lunar atmosphere and dust environment explorer (ladee) successfully mapped the dust density distribution over the lunar surface up to an altitude of ∼ 250 km. ldex detected dust grains launched off the surface in ejecta plumes generated by impacts of cometary and asteroid... | detecting meteoroid streams with an in-situ dust detector above an airless body |
the internal properties of cometary nuclei are the best clues to the size distribution and properties of the early planetesimals that formed the planets during the early solar system nebula processes. the consert radar was designed to probe the interior of comet 67p/churyumov-gerasimenko with a wavelength of about 3 m.... | consert constrains the internal structure of 67p at a few metres size scale |
context. molecular oxygen, nitrogen, and ozone have been detected on some satellites of saturn and jupiter, as well as on comets. they are also expected to be present in ice-grain mantles within star-forming regions. the continuous energetic processing of icy objects in the solar system induces physical and chemical ch... | vacuum ultraviolet photoabsorption spectroscopy of space-related ices: 1 kev electron irradiation of nitrogen- and oxygen-rich ices |
context. the southern hemisphere of comet 67p/churyumov-gerasimenko (67p) became observable by the rosetta mission in march 2015, a few months before cometary southern vernal equinox. the anhur region in the southern part of the comet's larger lobe was found to be highly eroded, enriched in volatiles, and highly active... | surface evolution of the anhur region on comet 67p/churyumov-gerasimenko from high-resolution osiris images |
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