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aims: the osiris camera onboard the rosetta spacecraft obtained close-up views of the dust coma of comet 67p. the jet structures can be used to trace their source regions and to examine the possible effect of gas-surface interaction.methods: we analyzed the wide-angle images obtained in the special dust observation seq... | morphology and dynamics of the jets of comet 67p/churyumov-gerasimenko: early-phase development |
the reaction of the nitrogen atom (n) in its first electronically excited state (2d) with cyanoacetylene (hc3n) has been investigated under single-collision conditions by using the crossed molecular beam method with mass spectrometric detection at a collision energy of 31 kj mol-1. with the support of electronic struct... | combined crossed molecular beams and computational study on the n(2d) + hcccn(x1σ+) reaction and implications for extra-terrestrial environments |
transmission electron microscope examination of more than 250 fragments, >1 μm from comet wild 2 and a giant cluster interplanetary dust particle (gcp) of probable cometary origin has revealed four new calcium-aluminum-rich inclusions (cais), an amoeboid olivine aggregate (aoa), and an additional aoa or al-rich chon... | refractory materials in comet samples |
previous work on protoplanetary dust growth shows a halt at centimeter sizes owing to the occurrence of bouncing at velocities of ≳0.1 m s-1 and fragmentation at velocities ≳1 m s-1. to overcome these barriers, spatial concentration of centimeter-sized dust pebbles and subsequent gravitational collapse have been propos... | the role of pebble fragmentation in planetesimal formation. i. experimental study |
laboratory spectral measurements of relevant analogue materials were performed in the framework of the rosetta mission in order to explain the surface spectral properties of comet 67p. fine powders of coal, iron sulphides, silicates and their mixtures were prepared and their spectra measured in the vis-ir range. these ... | laboratory simulations of the vis-nir spectra of comet 67p using sub-μm sized cosmochemical analogues |
nucleobases are the informational subunits of rna and dna and are essential to all known forms of life. the nucleobases can be divided into two groups of molecules: the pyrimidine-based compounds that include uracil, cytosine, and thymine, and the purine-based compounds that include adenine and guanine. previous work i... | the formation of nucleobases from the ultraviolet photoirradiation of purine in simple astrophysical ice analogues |
stars which pass close to the sun can perturb the oort cloud, injecting comets into the inner solar system where they may collide with the earth. using van leeuwen's re-reduction of the hipparcos data complemented by the original hipparcos and tycho-2 catalogues, along with recent radial velocity surveys, i integrate t... | close encounters of the stellar kind |
in 1977, while apple ii and atari computers were being sold, a tiny dot was observed in an inconvenient orbit. the minor body 1977 ub, to be named (2060) chiron, with an orbit between saturn and uranus, became the first centaur, a new class of minor bodies orbiting roughly between jupiter and neptune. the observed over... | from centaurs to comets - 40 years |
context. in 2020, the initial version of the stellar potential perturbers database (stepped) was presented with the aim to deliver up-to-date information on the stars and stellar systems that may perturb a long-period comet motion. we used the minimal distance between a star and the sun as a selecting tool when compili... | important stellar perturbers found during the stepped database update based on gaia edr3 data |
the electron-ion-positively charged dust plasma system containing boltzmann distributed electron species, cold inertial ion species, and stationary positively charged dust (pcd) species are considered. the roles of pcd species in the formation of ion-acoustic (ia) subsonic solitary waves (sws) are investigated by the p... | roles of positively charged dust in the formation of ion-acoustic subsonic solitary waves in electron-ion-positively charged dust plasmas |
context. the esa/rosetta mission has been orbiting comet 67p/churyumov-gerasimenko since august 2014, measuring its dayside plasma environment. the ion spectrometer onboard rosetta has detected two ion populations, one energetic with a solar wind origin (h+, he2+, he+), the other at lower energies with a cometary origi... | the atmosphere of comet 67p/churyumov-gerasimenko diagnosed by charge-exchanged solar wind alpha particles |
meteor showers and their outbursts are the dominant source of meteoroid impact risk to spacecraft on short time-scales. meteor shower prediction models depend on historical observations to produce accurate forecasts. however, the current lack of quality and persistent world-wide monitoring at optical meteoroid sizes ha... | computing optical meteor flux using global meteor network data |
context. ices are present in comets and in the mantles of interstellar grains. their chemical composition has been indirectly derived by observing molecules released in the gas phase, when comets approach the sun and when ice mantles are sublimated or destroyed, e.g. in the hot cores present in high-mass, star-forming ... | antifreeze in the hot core of orion. first detection of ethylene glycol in orion-kl |
the tunguska event remained enigmatic for almost 100 years until the collision of comet shoemaker-levy 9 with jupiter in 1994 helped to resolve this enigma and allowed us to adequately interpret the more recent chelyabinsk event. airbursts typically occur if a meteoroid entering earth's atmosphere is 10-100 m in diamet... | from tunguska to chelyabinsk via jupiter |
selection of a suitable low-pressure sprinkler can be an effective measure to reduce energy consumption, wind drift and evaporation losses. the crop canopy often redistributes the applied water during sprinkler irrigation. therefore, we investigated the water distributions above and below the canopy as well as their di... | water distributions of low-pressure sprinklers as affected by the maize canopy under a centre pivot irrigation system |
the solar wind is a highly turbulent medium exhibiting scalings of the fluctuations ranging over several decades of scales from the correlation length down to proton and electron gyroradii, thus suggesting a self-similar nature for these fluctuations. during its journey, the solar wind encounters the region of space su... | the effect of solar-wind turbulence on magnetospheric activity |
the lander philae, part of the esa rosetta mission successfully landed on comet 67p/churyumov- gerasimenko on november 12th, 2014. after several (unplanned) bounces it performed a first scientific sequence (fss), based on the energy stored in its on board batteries. all ten instruments of the payload aboard philae have... | rosetta lander - philae: operations on comet 67p/churyumov-gerasimenko, analysis of wake-up activities and final state |
the d/h ratio is a clue to the origin and evolution of hydrogen-bearing chemical species in solar system materials. d/h has been observed in the coma of many comets, but most such measurements have been for gaseous water. we present the first in situ measurements of the d/h ratios in the organic refractory component of... | d/h in the refractory organics of comet 67p/churyumov-gerasimenko measured by rosetta/cosima |
the magnetic field at a comet is significantly influenced by the solar wind on one side and the outgassing rate on the other. there are no simple spatial models for the magnetic field direction, neither at a comet with low outgassing rates (∼1025 s-1) where ion gyroradius effects are non-negligible, nor at high outgass... | evolution of the magnetic field at comet 67p/churyumov-gerasimenko |
the plasma of comet 67p/churyumov-gerasimenko is analyzed based on the rpc-mip mutual impedance probe data of the rosetta mission. numerical simulations of the rpc-mip instrumental response considering two populations of electrons were fit on experimental responses acquired from january to september 2016 to extract the... | plasma characterization at comet 67p between 2 and 4 au from the sun with the rpc-mip instrument |
the kinetic monte carlo method, used in astrochemistry to investigate suprathermal (hot) particles at the molecular level, is presented. different modifications of this method, aimed at studying the influence of suprathermal particles in the processes occurring in gas and dust envelopes surrounding astrophysical object... | suprathermal particles in astrochemistry |
measurements of the fractional momentum loss (sloss≡δ pt/pt ) of high-transverse-momentum-identified hadrons in heavy-ion collisions are presented. using π0 in au +au and cu +cu collisions at √{snn}=62.4 and 200 gev measured by the phenix experiment at the relativistic heavy ion collider and and charged hadrons in pb +... | scaling properties of fractional momentum loss of high-pt hadrons in nucleus-nucleus collisions at √{sn n} from 62.4 gev to 2.76 tev |
aims: we aim at analytically modelling the solar wind proton trajectories during their interaction with a partially ionised cometary atmosphere, not in terms of bulk properties of the flow but in terms of single particle dynamics.methods: we first derive a generalised gyromotion, in which the electric field is reduced ... | solar wind dynamics around a comet. a 2d semi-analytical kinetic model |
context. the electron temperature of the plasma is one important aspect of the environment. electrons created by photoionization or impact ionization of atmospheric gas have energies 10 ev. in an active comet coma, the gas density is high enough for rapid cooling of the electron gas to the neutral gas temperature (a fe... | cold electrons at comet 67p/churyumov-gerasimenko |
understanding the history and evolution of small bodies, such as dust grains and comets, in planet-forming disks is very important to reveal the architectural laws responsible for the creation of planetary systems. these small bodies in cold regions of the disks are typically considered to be mixtures of dust particles... | temperature programmed desorption of water ice from the surface of amorphous carbon and silicate grains as related to planet-forming disks |
the international rosetta mission was launched on 2nd march 2004 on its 10 year journey to rendezvous with comet 67p churyumov-gerasimenko. rosetta performed comet orbit insertion on the 6th of august 2014, after which it characterised the nucleus and orbited it at altitudes as low as a few kilometres. in november 2014... | the final year of the rosetta mission |
winds from asymptotic giant branch (agb) stars not only provide mass and energy return, but also produce dust grains in massive elliptical galaxies. due to the fast stellar velocity, the wind is thought to form a comet-like tail, similar to mira in the local bubble. many massive elliptical galaxies and cluster centrals... | the fate of asymptotic giant branch winds in massive galaxies and the intracluster medium |
we consider a space-time continuous directed polymer in random environment. the path is brownian and the medium is poissonian. we review many results obtained in the last decade, and also we present new ones. in this fundamental setup, we can make use of fine formulas and strong tools from stochastic analysis for gauss... | brownian polymers in poissonian environment: a survey |
this paper presents the past evolution of the orbital elements of comet 67p/churyumov-gerasimenko, target of the rosetta spacecraft. the gravitational orbit of the comet is affected by the sublimation of ice from the nucleus that triggers non-gravitational forces. the comet also experienced several close encounters wit... | the recent dynamical history of comet 67p/churyumov-gerasimenko |
we examine the massive colliding cluster el gordo, one of the most massive clusters at high redshift. we use a free-form lensing reconstruction method that avoids making assumptions about the mass distribution. we use data from the relics program and identify new multiply lensed system candidates. the new set of constr... | free-form lens model and mass estimation of the high-redshift galaxy cluster act-cl j0102-4915, "el gordo" |
we present visible and mid-infrared imagery and photometry of temporary jovian co-orbital comet p/2019 ld2 taken with hubble space telescope/wide field camera 3 (hst/wfc3), spitzer space telescope/infrared array camera (spitzer/irac), and the growth telescope network, visible spectroscopy from keck/low-resolution imagi... | initial characterization of active transitioning centaur, p/2019 ld2 (atlas), using hubble, spitzer, ztf, keck, apache point observatory, and growth visible and infrared imaging and spectroscopy |
the neutral and plasma environment is critical in understanding the interaction of the solar wind and comet 67p/churyumov-gerasimenko (cg), the target of the european space agency's rosetta mission. to serve this need and support the rosetta mission, we have developed a 3-d four-fluid model, which is based on bats-r-us... | four-fluid mhd simulations of the plasma and neutral gas environment of comet 67p/churyumov-gerasimenko near perihelion |
context. after the landing of philae, consert probed the nucleus of 67p/churyumov-gerasimenko (67p) and observed no heterogeneities at metric scale within the probed part of the small lobe of 67p. further studies have then quantified the observed homogeneity in terms of maximum permittivity contrast versus the typical ... | homogeneity of 67p/churyumov-gerasimenko as seen by consert: implication on composition and formation |
pockmarks consists of depressions on the seafloor and are often considered to originate from fluid escape activities. in this study, we report 125 pockmarks near the andu seamount in the southern margin of the south china sea (scs) and preliminarily investigate their genesis based on multi-beam bathymetry and multichan... | a preliminary study on morphology and genesis of giant and mega pockmarks near andu seamount, nansha region (south china sea) |
carbon-based nanomaterials are being increasingly used, demanding strong information to support their safety in terms of human health. as ingestion is one of the most important exposure routes in humans, we have determined their potential risk by using an in vitro model simulating the human intestinal barrier and evalu... | interactions of graphene oxide and graphene nanoplatelets with the in vitro caco-2/ht29 model of intestinal barrier |
because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67p/churyumov-gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. based on the osiris imaging observations of the outgassing effect, a simple model of surface su... | gas outflow and dust transport of comet 67p/churyumov-gerasimenko |
we report on the detection and characterization of more than 6300 polygons on the surface of the nucleus of comet 67p/churyumov-gerasimenko, using images acquired by the osiris camera onboard rosetta between august 2014 and march 2015. they are found in consolidated terrains and grouped in localized networks. they are ... | meter-scale thermal contraction crack polygons on the nucleus of comet 67p/churyumov-gerasimenko |
infrared (ir) band strengths are needed to extract accurate molecular abundances from astronomical observations of interstellar and solar system ices. however, laboratory measurements of such intensities often have required multiple assumptions about ice composition and thickness. here we describe a method that circumv... | a new method for measuring infrared band strengths in h2o ices: first results for ocs, h2s, and so2 |
the high obliquity (~50°) of comet 67p/churyumov-gerasimenko (67p) is responsible for a long-lasting winter polar night in the southern regions of the nucleus. we report observations made with the submillimeter and millimeter continuum channels of the microwave instrument onboard the rosetta orbiter (miro) of the therm... | dark side of comet 67p/churyumov-gerasimenko in aug.-oct. 2014. miro/rosetta continuum observations of polar night in the southern regions |
we present a complete census of the 14n/15n isotopic ratio in the most abundant n-bearing molecules toward the cold envelope of the protocluster omc-2 fir4, the best known sun progenitor. to this scope, we analyzed the unbiased spectral survey obtained with the iram 30 m telescope at 3, 2, and 1 mm. we detected several... | first measurement of the 14n/15n ratio in the analog of the sun progenitor omc-2 fir4 |
we present the ion composition in the coma of comet 67p with newly detected ion species over the 28-37 u mass range, probed by rosetta orbiter spectrometer for ion and neutral analysis (rosina)/double focusing mass spectrometer (dfms). in summer 2015, the nucleus reached its highest outgassing rate and ion-neutral reac... | ion composition at comet 67p near perihelion: rosetta observations and model-based interpretation |
here we try to find the origin of 1i/2017 u1 'oumuamua, the first interstellar object recorded inside the solar system. to this aim, we searched for close encounters between 'oumuamua and all nearby stars with known kinematic data during their past motion. we had checked over 200 thousand stars and found just a handful... | investigating the dynamical history of the interstellar object 'oumuamua |
the isotopic ratio of nitrogen in nearby protoplanetary disks, recently measured in cn and hcn, indicates that a fractionated reservoir of volatile nitrogen is available at the earliest stage of comet formation. this reservoir also presents a 3:1 enrichment in 15n relative to the elemental ratio of 330, identical to th... | abundance of hcn and its c and n isotopologues in l1498 |
evidence for long-lived sources of cryovolcanism on the nucleus of the comet 29p/schwassmann-wachmann has been found from a study of its times of outburst (t0) and the morphological development of inner coma structures. analysis of data from the minor planet center observations archive spanning 2002-2014 and other obse... | discrete sources of cryovolcanism on the nucleus of comet 29p/schwassmann-wachmann and their origin |
the nonlinear propagation of dust acoustic (da) waves (daws) in an unmagnetized electron depleted dusty plasma (containing opposite polarity warm dust grains and non-extensive positive ions) has been theoretically investigated. the nonlinear schrödinger equation (nlse) is derived by employing the reductive perturbation... | dust-acoustic envelope solitons and rogue waves in an electron depleted plasma |
context. comets are primitive objects, remnants of the volatile-rich planetesimals from which the solar system condensed. knowing their structure and composition is thus crucial for the understanding of our origins. after the successful landing of philae on the nucleus of 67p/churyumov-gerasimenko in november 2014, for... | electrical properties and porosity of the first meter of the nucleus of 67p/churyumov-gerasimenko. as constrained by the permittivity probe sesame-pp/philae/rosetta |
sublimating gas molecules scatter off of the surface of an icy body in the same manner as photons (lambertian scattering). this means that for every photon-driven body force, there should be a sublimation-driven analog that affects icy bodies. thermal photons emitted from the surfaces of asymmetrically shaped bodies in... | the formation of striae within cometary dust tails by a sublimation-driven yorp-like effect |
we present a model of cometary dust capable of simulating the dynamics within the first few tens of km of the comet surface. recent measurements by the grain impact analyser and dust accumulator and cometary secondary ion mass analyser instruments on rosetta show that the nucleus emits fluffy dust particles with porosi... | acceleration of cometary dust near the nucleus: application to 67p/churyumov-gerasimenko |
to explore the hypothesis that kic 8462852's aperiodic dimming is caused by artificial megastructures in orbit, rather than a natural cause such as cometary fragments in a highly elliptical orbit, we searched for electromagnetic signals from kic 8462852 indicative of extraterrestrial intelligence. the primary observati... | optical seti observations of the anomalous star kic 8462852 |
we obtained broad- and narrowband images of the hyperactive comet 46p/wirtanen on 33 nights during its 2018/2019 apparition, when the comet made a historic close approach to the earth. with our extensive coverage, we investigated the temporal behavior of the comet on both seasonal and rotational timescales. we used cn ... | narrowband observations of comet 46p/wirtanen during its exceptional apparition of 2018/19. i. apparent rotation period and outbursts |
multi-band photometric monitoring of comet 29p/schwassmann-wachmann 1 was conducted with the standard johnson-cousins filter set. observations extended from 2018 july to 2021 december. the comet was detected to show at least 12 relatively large outbursts, during which its brightness increased by 1.5 to 5 mag as measure... | long-term monitoring of comet 29p/schwassmann-wachmann from the lulin observatory |
we report observations of colour in the inner coma of comet c/2013 uq4 (catalina) with the broad-band b and r filters. we find significant temporal variations of the colour slope, ranging from -12.67 ± 8.16% per 0.1 μm to 35.09 ± 11.70% per 0.1 μm. it is significant that the comet changes colour from red to blue over a... | colour variations of comet c/2013 uq4 (catalina) |
the jupiter-family comet (jfc) 46p/wirtanen passed the earth at a distance of 0.077 au on 2018 december 16 ut, presenting a rare opportunity to study the chemical structure of its coma. with the james clerk maxwell telescope we achieved a resolution of 800 km, which is smaller than the scale lengths of some distributed... | james clerk maxwell telescope spectral and continuum imaging of hyperactive comet 46p/wirtanen |
magnesium stable isotope ratios and minor element abundances of five olivine particles from comet 81p/wild 2 were examined by secondary ion mass spectrometry (sims). wild 2 olivine particles exhibit only small variations in δ25mg values from -1.0 +0.4/-0.5‰ to 0.6 +0.5/-0.6‰ (2σ). this variation can be simply explained... | correlated isotopic and chemical evidence for condensation origins of olivine in comet 81p/wild 2 and in aoas from cv and co chondrites |
many efforts have been made in the last 30 years to develop more relevant in vitro models to study genotoxic responses of drugs and environmental contaminants. while 2d heparg cells are one of the most promising models for liver toxicology, a switch to 3d cultures that integrate both in vivo architecture and cell-cell ... | three-dimensional heparg spheroids as a liver model to study human genotoxicity in vitro with the single cell gel electrophoresis assay |
after 3/2013 in sky over kiev we registered falling >12 of cometary nuclei fragments, 5 large and a few dozen of small meteoroid fragments. | observations of twilight bolide with using of ``churyumov fireball network'' |
the universe is molecularly rich, comprising from the simplest molecule (h2) to complex organic molecules (e.g., ch3cho and nh2cho), some of which of biological relevance (e.g., amino acids). this chemical richness is intimately linked to the different physical phases forming solar-like planetary systems, in which at e... | computational surface modelling of ices and minerals of interstellar interest—insights and perspectives |
sublimation, the direct transition from solid to gas phase, is a process responsible for shaping and changing the reflectance properties of many solar system surfaces. in this study, we have characterized the evolution of the structure/texture and of the visible and near-infrared (vis-nir) spectral reflectance of surfa... | sublimation of ice-tholins mixtures: a morphological and spectro-photometric study |
we processed images taken with the hubble space telescope(hst) to investigate any morphological features in the inner coma suggestive of a peculiar activity on the nucleus of the interstellar comet 2i/borisov. the coma shows an evident elongation, in the position angle (pa) ∼0-180○ direction, which appears related to t... | interstellar comet 2i/borisov exhibits a structure similar to native solar system comets |
we characterized the 67p/churyumov-gerasimenko's dust activity, by analysing individual dust particle velocity and momentum measurements of grain impact analyser and dust accumulator (giada), the dust detector onboard the esa/rosetta spacecraft, collecting dust from tens to hundreds of kilometres from the nucleus. spec... | 67p/churyumov-gerasimenko's dust activity from pre- to post-perihelion as detected by rosetta/giada |
ion-neutral chemical reactions are important in several areas of chemistry, including in some regions of the interstellar medium, planetary atmospheres, and comets. reactions of ccl+ with c2h2 are measured, and the main products include c3h2+ and c3h+, both relevant in extraterrestrial environments. accurate branching ... | reactions of translationally cold trapped ccl+ with acetylene (c2h2) |
we report on photometry and imaging of the jupiter family comets 41p/tuttle-giacobini-kresak and 45p/honda-mrkos-pajdusakova with the trappist-north (transiting planets and planetesimals small telescope) telescope. we observed 41p on 34 nights from february 16 to july 27, 2017, pre- and post-perihelion (rh = 1.04 au), ... | monitoring of the activity and composition of comets 41p/tuttle-giacobini-kresak and 45p/honda-mrkos-pajdusakova |
context. the rosetta spacecraft escorted comet 67p/churyumov-gerasimenko from 2014 to september 2016. the mission provided in situ observations of the cometary plasma during different phases of the cometary activity, which enabled us to better understand its evolution as a function of heliocentric distance.aims: in thi... | plasma properties of suprathermal electrons near comet 67p/churyumov-gerasimenko with rosetta |
the gateway centaur and jupiter co-orbital p/2019 ld2 (atlas) provides the first opportunity to observe the migration of a solar system small body from a centaur orbit to a jupiter family comet (jfc) four decades from now. the gateway transition region is beyond where water ice can power cometary activity, and coma pro... | contemporaneous multiwavelength and precovery observations of the active centaur p/2019 ld2 (atlas) |
we present initial time-resolved observations of the split comet 332p/ikeya-murakami taken using the hubble space telescope. our images reveal a dust-bathed cluster of fragments receding from their parent nucleus at projected speeds in the range 0.06-3.5 m s-1 from which we estimate ejection times from 2015 october to ... | fragmentation kinematics in comet 332p/ikeya-murakami |
we review the reservoirs of methane clathrates that may exist in the different bodies of the solar system. methane was formed in the interstellar medium prior to having been embedded in the protosolar nebula gas phase. this molecule was subsequently trapped in clathrates that formed from crystalline water ice during th... | methane clathrates in the solar system |
although the debate regarding the origin of the cyano (cn) radical in comets has been ongoing for many decades, it has yielded no definitive answer to date. cn could previously only be studied remotely, strongly hampering efforts to constrain its origin because of very limited spatial information. thanks to the europea... | first in situ detection of the cn radical in comets and evidence for a distributed source |
in the paper the migration of dust and ice grains over the surface of the comet nucleus is considered and analysed. this phenomenon is a consequence of interplay between the components of three forces tangential to the surface of comet nucleus and acting on the comet's grain. these forces are the gravity of the comet's... | on migration of dust and ice grains on the surface of the rotating comet nucleus |
context. the recently announced oort-cloud comet c/2014 un271 (bernardinelli-bernstein) is remarkable in at least three respects: (i) it was discovered inbound as far as ∼29 au from the sun (with prediscovery images up to ∼34 au); (ii) it already showed cometary activity at almost 24 au; and (iii) its nuclear magnitude... | size and albedo of the largest detected oort-cloud object: comet c/2014 un271 (bernardinelli-bernstein) |
in 2015 august, comet 67p/churyumov-gerasimenko, the target comet of the esa rosetta mission, reached its perihelion at ∼1.24 au. here, we estimate for a three-day period near perihelion, effective ion speeds at distances ∼200-250 km from the nucleus. we utilize two different methods combining measurements from the ros... | effective ion speeds at ∼200-250 km from comet 67p/churyumov-gerasimenko near perihelion |
a hierarchical model of microstructure of cometary dust seems to accurately capture the morphological complexity of these particles as observed by the rosetta mission to the 67p/churyumov-gerasimenko. the main aim of this work is to investigate how uncertainties in the knowledge of the microstructure of the surface lay... | the effect of hierarchical structure of the surface dust layer on the modelling of comet gas production |
the cometary secondary ion mass analyzer (cosima) collects dust particles in the coma of 67p/churyumov-gerasimenko, images them with a resolution of 14 μm × 14 μm, and measures their composition via time-of-flight secondary ion mass spectrometry. the particles are collected on targets exposed to the cometary flux for p... | evolution of the physical properties of dust and cometary dust activity from 67p/churyumov-gerasimenko measured in situ by rosetta/cosima |
proper droplet diameter and kinetic energy can effectively reduce the risk of soil erosion during low‑pressure sprinkler irrigation. in this study, we comprehensively evaluated the radial distributions of droplet diameter, velocity, kinetic energy, kinetic energy per unit droplet volume, and specific power for three co... | comprehensively evaluating and modelling droplet diameters and kinetic energies of low‑pressure sprinklers |
the rosetta spacecraft of the european space agency made ground-breaking observations of comet 67p/churyumov-gerasimenko and of its cometary environment. we search for magnetic holes in that environment, i.e., significant depressions in the magnetic field strength, measured by the rosetta fluxgate magnetometer (mag) in... | first observations of magnetic holes deep within the coma of a comet |
a comet is a highly dynamic object, undergoing a permanent state of change. these changes have to be carefully classified and considered according to their intrinsic temporal and spatial scales. the rosetta mission has, through its contiguous in-situ and remote sensing coverage of comet 67p/churyumov-gerasimenko (herea... | cometary comae-surface links |
the provenance of gems (glass with embedded metal and sulfides) in cometary type interplanetary dust particles is investigated using analytical scanning transmission electron microscopy and secondary ion mass spectrometry. we review the current state of knowledge and closely examine the densities, elemental composition... | on the provenance of gems, a quarter century post discovery |
mercury’s surface is darker than that of the moon. iron-bearing minerals and submicroscopic metallic iron produced by space weathering are the primary known darkening materials on airless bodies. yet mercury’s iron abundance at the surface is lower than the moon’s; another material is therefore likely to be responsible... | darkening of mercury's surface by cometary carbon |
alice is a far-ultraviolet imaging spectrograph on board rosetta that, among multiple objectives, is designed to observe emissions from various atomic and molecular species from within the coma of comet 67p/churyumov-gerasimenko. the initial observations, made following orbit insertion in 2014 august, showed emissions ... | the nature and frequency of the gas outbursts in comet 67p/churyumov-gerasimenko observed by the alice far-ultraviolet spectrograph on rosetta |
context. after the successful landing of philae on the nucleus of 67p/churyumov-gerasimenko, the rosetta mission provided the first opportunity of performing measurements with the consert tomographic radar in november 2014. consert data were acquired during this first science sequence. they unambiguously showed that pr... | consert suggests a change in local properties of 67p/churyumov-gerasimenko's nucleus at depth |
interstellar ice is believed to be a cradle of complex organic compounds, commonly found within icy comets and interstellar clouds, in association with ultraviolet (uv) irradiation and subsequent warming. we found that uv-irradiated amorphous ices composed of h2o, ch3oh, and nh3 and of pure h2o behave like liquids over... | liquid-like behavior of uv-irradiated interstellar ice analog at low temperatures |
context. the esa rosetta mission has been investigating the environment of comet 67p/churyumov-gerasimenko (67p) since august 2014. among the experiments on board the spacecraft, the rosina experiment (rosetta orbiter spectrometer for ion and neutral analysis) includes two mass spectrometers to analyse the composition ... | the heterogeneous coma of comet 67p/churyumov-gerasimenko as seen by rosina: h2o, co2, and co from september 2014 to february 2016 |
context. from august 2014 to september 2016, rosetta escorted comet 67p/churyumov-gerasimenko (67p) during its journey around the sun. one of the aims of rosetta was to characterize cometary activity and the consequent formation of dust flux structures in cometary comae.aims: we characterize and quantify the submicrome... | giada microbalance measurements on board rosetta: submicrometer- to micrometer-sized dust particle flux in the coma of comet 67p/churyumov-gerasimenko |
knowledge of the magnetization of planetary bodies constrains their origin and evolution, as well as the conditions in the solar nebular at that time. on the basis of magnetic field measurements during the descent and subsequent multiple touchdown of the rosetta lander philae on the comet 67p/churyumov-gerasimenko (67p... | the nonmagnetic nucleus of comet 67p/churyumov-gerasimenko |
abundant molecular oxygen was discovered in the coma of comet 67p/churyumov-gerasimenko. its origin was ascribed to primordial gaseous o2 incorporated into the nucleus during the comet's formation. this thesis was put forward after discounting several o2 production mechanisms in comets, including photolysis and radioly... | dynamic molecular oxygen production in cometary comae |
the optical, spectroscopic, and infrared remote imaging system (osiris) onboard the european space agency's rosetta spacecraft acquired images of comet 67p/churyumov-gerasimenko (67p) and its surrounding dust coma starting from may 2014 until september 2016. in this paper we present methods and results from analysis of... | on deviations from free-radial outflow in the inner coma of comet 67p/churyumov-gerasimenko |
people have probably been watching the sky since the beginning of human history. observers in pre-telescopic ages recorded anomalous events, which now provide uniquely valuable information for modern scientists. records that include drawings are particularly useful, since the verbal expressions recorded by pre-telescop... | the earliest drawings of datable auroras and a two-tail comet from the syriac chronicle of zūqnīn |
context. this paper describes the modelling of gas and dust data acquired in the period august to october 2014 from the european space agency's rosetta spacecraft when it was in close proximity to the nucleus of comet 67p/churyumov-gerasimenko.aims: with our 3d gas and dust comae models this work attempts to test the h... | cliffs versus plains: can rosina/cops and osiris data of comet 67p/churyumov-gerasimenko in autumn 2014 constrain inhomogeneous outgassing? |
sublimative outgassing of comets produces torques that alter the rotation state of their nuclei. recently, parameterized sublimative torque models have been developed to study rotation state changes of individual comet nuclei and populations of cometary bodies. however, these models simplify the interactions between th... | the sublimative torques of jupiter family comets and mass wasting events on their nuclei |
this paper studies the transition probabilities of electric dipole transitions between 10 low-lying states of the cn radical. these states are x2σ+, a2π, b2σ+, a4σ+, b4π, 14σ-, 24π, 14δ, 16σ+, and 16π. the potential energy curves are calculated using the casscf method, which is followed by the icmrci approach with the ... | transition dipole moments and transition probabilities of the cn radical |
deep chandra acis observations of the region around the putative pulsar, cxou j061705.3+222127, in the supernova remnant (snr) ic 443 reveal an ∼5″ radius ring-like structure surrounding the pulsar and a jet-like feature oriented roughly north-south across the ring and through the pulsar's location at 06h17m5.ˢ200 + 22... | high spatial resolution x-ray spectroscopy of the ic 443 pulsar wind nebula and environs |
comet c/2013 us10 (catalina) was a dynamically new oort cloud comet whose apparition presented a favorable geometry for observations near close-earth approach (≃0.93 au) at heliocentric distances ≲2 au when insolation and sublimation of volatiles drive maximum activity. here we present mid-infrared 6.0 ≲ λ(μm) ≲ 40 spe... | the coma dust of comet c/2013 us10 (catalina): a window into carbon in the solar system |
recent observations show activity in long-period comet c/2017 k2 at heliocentric distances beyond the orbit of uranus. with this as motivation, we constructed a simple model that takes a detailed account of gas transport modes and simulates the time-dependent sublimation of supervolatile ice from beneath a porous mantl... | cometary activity beyond the planets |
between 2014 december 31 and 2015 march 17, the osiris cameras on rosetta documented the growth of a $140\, \mathrm{\hbox{-}m}$ wide and $0.5\, \mathrm{\hbox{-}m}$ deep depression in the hapi region on comet 67p/churyumov-gerasimenko. this shallow pit is one of several that later formed elsewhere on the comet, all in s... | co2-driven surface changes in the hapi region on comet 67p/churyumov-gerasimenko |
the solar system formed from interstellar dust and gas in a molecular cloud. astronomical observations show that typical interstellar dust consists of amorphous (a-) silicate and organic carbon. bona fide physical samples for laboratory studies would yield unprecedented insight about solar system formation, but they we... | multiple generations of grain aggregation in different environments preceded solar system body formation |
organic compounds have been delivered over time to mars via meteorites, comets and interplanetary dust particles. the fate of organic material on the surface of mars must be affected by the martian environment, in particular by ultraviolet (uv) and other ionizing radiation. penetration depth of uv radiation into soils ... | shielding biomolecules from effects of radiation by mars analogue minerals and soils |
two major questions regarding comets have been up to now far from any solution. (i) how is it possible that water-ice sublimation from the nucleus surface does not lead to an insulating crust, stopping every gas and dust ejection within a few days? (ii) how is it possible that the gas flow crossing the refractory surfa... | how comets work |
in 2017 april, we acquired comprehensive high-resolution spectra of newly discovered comet c/2017 e4 (lovejoy) as it approached perihelion, and before its disintegration. we detected many cometary emission lines in the range (2.8-5.3) μm, in four customized instrument settings (l1-c, l3, lp1-c, and m1) of ishell—the ne... | the volatile composition of comet c/2017 e4 (lovejoy) before its disruption, as revealed by high-resolution infrared spectroscopy with ishell at the nasa/irtf |
cometary outbursts, i.e. a sudden increase in brightness, have aroused astronomers' curiosity since the 1920s (hughes). in 1927, comet 29p/schwassmann-wachmann 1 was discovered, probably at the maximum of one of its outbursts. many authors have tried to explain the source of cometary outbursts. they formed various mode... | a model of cometary outbursts: a new simple approach to the classical question |
context. on 12 march 2015 the osiris wac camera onboard the esa rosetta spacecraft orbiting comet 67p/churyumov-gerasimenko observed a small outburst originating from the imhotep region at the foot of the big lobe of the comet. these measurements are unique since it was the first time that the initial phase of a transi... | a mini outburst from the nightside of comet 67p/churyumov-gerasimenko observed by the osiris camera on rosetta |
we report and analyze updated molecular abundances in 20 comets obtained by employing modern data reduction procedures and molecular models. using box and scatter plots, we examine how the different molecular species are distributed among the comet population, while by means of pie charts, we investigate the relative p... | investigation of the origins of comets as revealed through infrared high-resolution spectroscopy i. molecular abundances |
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