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context. the change in rotation period and the orientation of the rotation axis of comet 67p/churyumov-gerasimenko (67p) can be deduced with high precision from images taken by the scientific imaging instruments on board the rosetta mission. non-gravitational forces are a natural explanation for these data.aims: we des... | comet 67p/churyumov-gerasimenko rotation changes derived from sublimation-induced torques |
context. it has recently been proposed that the surface composition of icy main-belt asteroids (b-, c-, cb-, cg-, p-, and d-types) may be consistent with that of chondritic porous interplanetary dust particles (cp idps).aims: in the light of this new association, we re-examine the surface composition of a sample of ast... | compositional characterisation of the themis family |
epic 204278916 has been serendipitously discovered from its k2 light curve that displays irregular dimmings of up to 65 per cent for ≈25 consecutive days out of 78.8 d of observations. for the remaining duration of the observations, the variability is highly periodic and attributed to stellar rotation. the star is a yo... | the peculiar dipping events in the disc-bearing young-stellar object epic 204278916 |
beginning in 2014 march, the osiris (optical, spectroscopic, and infrared remote imaging system) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67p/churyumov-gerasimenko using both the wide angle camera (wac) and the narrow angle camera (nac). the many observations taken since july of 20... | sublimation of icy aggregates in the coma of comet 67p/churyumov-gerasimenko detected with the osiris cameras on board rosetta |
after coming to rest on the night side of comet 67p/churyumov-gerasimenko, the rolis camera on-board rosetta's philae lander acquired five images of the surface below the lander, four of which were with the aid of led illumination of different colors. the images confirm that philae was perched on a sloped surface. a lo... | close-up images of the final philae landing site on comet 67p/churyumov-gerasimenko acquired by the rolis camera |
context. the population of comets hosted by the oort cloud is heterogeneous. most studies in this area have focused on highly active objects, those with small perihelion distances or examples of objects with peculiar physical properties and/or unusual chemical compositions. this may have produced a biased sample of oor... | spectroscopic and dynamical properties of comet c/2018 f4, likely a true average former member of the oort cloud |
the origin of the chicxulub impactor, which is attributed as the cause of the k/t mass extinction event, is an unsolved puzzle. the background impact rates of main-belt asteroids and long-period comets have been previously dismissed as being too low to explain the chicxulub impact event. here, we show that a fraction o... | breakup of a long-period comet as the origin of the dinosaur extinction |
context. detection of abundant o2 at 1-10% relative to h2o ice in the comae of comets 1p/halley and 67p/churyumov-gerasimenko has motivated attempts to explain the origin of the high o2 ice abundance. recent chemical modelling of the outer, colder regions of a protoplanetary disk midplane has shown production of o2 ice... | formation of cometary o2 ice and related ice species on grain surfaces in the midplane of the pre-solar nebula |
the discrete element method (dem) is frequently used to model complex granular systems and to augment the knowledge that we obtain through theory, experimentation, and real-world observations. numerical simulations are a particularly powerful tool for studying the regolith-covered surfaces of asteroids, comets, and sma... | validating n-body code chrono for granular dem simulations in reduced-gravity environments |
a deep understanding of the origin of life requires the physical, chemical, and biological study of prebiotic systems and the comprehension of the mechanisms underlying their evolutionary steps. in this context, great attention is paid to the class of interstellar molecules known as "complex organic molecules" (coms), ... | astrochemical pathways to complex organic and prebiotic molecules: experimental perspectives for in situ solid-state studies |
the calcium-aluminum-rich inclusions (cais) found in chondritic meteorites are probably the oldest solar system solids, dating back to 4567.30 ± 0.16 million years ago. they are thought to have formed in the protosolar nebula within a few astronomical units of the sun, and at a temperature of around 1300 k. the stardus... | searching for calcium-aluminum-rich inclusions in cometary particles with rosetta/cosima |
this paper discusses an algorithm for detecting single transits in photometric time-series data. specifically, we aim to identify asymmetric transits with ingress that is more rapid than egress, as expected for cometary bodies with a significant tail. the algorithm is automated, so can be applied to large samples and o... | an automated search for transiting exocomets |
three different measurement campaigns have resulted in three drastically different sets of color measurements of comet 41p/tuttle-giacobini-kresák, ranging from a strongly red to a strongly blue color. although the color slope is normalized to the wavelength range between the filters used, this only serves to partially... | resolving color differences of comet 41p/tuttle-giacobini-kresák |
the rosetta spacecraft observations revealed that the nucleus of comet 67p/churyumov-gerasimenko consists of two similarly sized lobes connected by a narrow neck. here, we evaluate the possibility that 67p is a collapsed binary. we assume that the progenitor of 67p was a binary and consider various physical mechanisms ... | bi-lobed shape of comet 67p from a collapsed binary |
we report results of polarimetric observations of comet 21p/giacobini-zinner made at phase angles, α ≈ 76-78°, between 10 and 17 of september 2018, and compare them with previous measurements. we find significant variations in the polarimetric signals that appear consistent with those reported previously. these variati... | imaging polarimetry and photometry of comet 21p/giacobini-zinner |
despite extensive effort during the last four decades, no clear signature of a lunar indigenous noble gas component has been found. in order to further investigate the possible occurrence of indigenous volatiles in the moon, we have re-analyzed the noble gas and nitrogen isotopic compositions in three anorthosite sampl... | stepwise heating of lunar anorthosites 60025, 60215, 65315 possibly reveals an indigenous noble gas component on the moon |
since 1950 when oort published his paper on the structure of the cloud of comets it is believed that stars passing near this hypothetical cometary reservoir play an important role in the dynamical evolution of long-period comets and injecting them into the observability region of the solar system. the aim of this paper... | first stars that could significantly perturb comet motion are finally found |
the earth's extraterrestrial dust flux includes a wide variety of dust particles that include feni metallic grains. during their atmospheric entry iron micrometeoroids melt and oxidize to form cosmic spherules termed i-type spherules. these particles are chemically resistant and readily collected by magnetic separation... | the origins of i-type spherules and the atmospheric entry of iron micrometeoroids |
shortly after the rosetta mission's rendezvous with 67p/churyumov-gerasimenko the rpc/ies instrument intermittently detected negative particles that were identified as singly charged nano-dust grains. these grains were recorded as a nearly mono-energetic beam of particles in the 200-500 ev range arriving from the direc... | negatively charged nano-grains at 67p/churyumov-gerasimenko |
context. the scattering of light by an asteroid's surface depends on the properties of its particles, volume density, and roughness. it is described by the reflection coefficient which, upon integration over the illuminated and observed part of the surface, yields the disk-integrated photometric brightness of the aster... | disk-integrated brightness of a lommel-seeliger scattering ellipsoidal asteroid |
we previously showed that farmers in bolivia are exposed to many pesticides, some at elevated levels, and that this was associated with increased risk of genetic damage. to improve the understanding of possible mixture effects, the cytotoxicity and genotoxicity of pesticides were studied in vitro using human liver hepg... | in vitro cytotoxicity and genotoxicity of single and combined pesticides used by bolivian farmers |
alteration processes on asteroid and comet surfaces, such as thermal fracturing, (micrometeorite) impacts or volatile outgassing, are complex mechanisms that form diverse surface morphologies and roughness on various scales. these mechanisms and their interaction may differ on the surfaces of different bodies. asteroid... | surface roughness of asteroid (162173) ryugu and comet 67p/churyumov-gerasimenko inferred from in situ observations |
we present high spectral resolution (r ∼ 110 000) ca ii k-line (3933 å) absorption profiles observed towards 20 nearby a-type stars thought to possess circumstellar debris discs. the stars were repeatedly observed over three nights on the 3.6m eso telescope (chile) during 2016 november. these spectra have revealed four... | further detections of exocomet absorbing gas around southern hemisphere a-type stars with known debris discs |
we show observational evidence for a new form of collisionless shock in interplanetary space near mars, small-scale shocks with periodic spacings. pickup of new ionized hydrogen atoms in a magnetic field aligned with the solar wind direction causes the generation of a magnetosonic wave train through an ion beam instabi... | observational evidence for fast mode periodic small-scale shocks: a new type of plasma phenomenon |
on 8 october 2011, the draconid meteor shower (iau, dra) was predicted to cause two brief outbursts of meteors, visible from locations in europe. for the first time, a european airborne meteor observation campaign was organized, supported by ground-based observations. two aircraft were deployed from kiruna, sweden, car... | the 2011 draconids: the first european airborne meteor observation campaign |
context. an open question in the study of comets is the so-called cohesion bottleneck, that is, how dust particles detach from the nucleus.aims: we test whether the co pressure buildup inside the pebbles of which cometary nuclei consist can overcome this cohesion bottleneck.methods: a recently developed pebble-diffusio... | co-driven activity constrains the origin of comets |
in recent decades, light pollution of the night sky has become a burning issue for all humanity. the negative impact of this state of affairs is particularly burdensome for the living organisms such as humans, animals, and plants, as well as for the whole ecosystems. in addition, it has a particularly negative impact o... | visibility of comets during their outbursts and the night sky light pollution—use the bortle scale |
the so-called “early activity” of comet 67p/churyumov-gerasimenko has been observed to originate mostly in parts of the concave region or “neck” between its two lobes. since activity is driven by the sublimation of volatiles, this is a puzzling result because this area is less exposed to the sun and is therefore expect... | rapid temperature changes and the early activity on comet 67p/churyumov-gerasimenko |
caiman latirostris is one of the two species of the order crocodylia that inhabit argentina and is considered a species of vital ecological and economic importance in the north-east of argentina. in this region, pesticides are the most common contaminants in natural environments and wild caiman populations are subject ... | a comprehensive approach using multiple biomarkers to detect damage induced by pesticides in broad-snouted caiman (caiman latirostris) under ex-situ conditions |
between 14 and 20 july 2018, small unmanned aircraft systems (uass) were deployed to the san luis valley of colorado (usa) alongside surface-based remote sensors, in situ sensors, and radiosonde systems as part of the lower atmospheric profiling studies at elevation - a remotely-piloted aircraft team experiment (lapse-... | measurements from mobile surface vehicles during the lower atmospheric profiling studies at elevation - a remotely-piloted aircraft team experiment (lapse-rate) |
in this work sublimation of porous water ice in vacuum is investigated. the experiments were performed at low temperature gradient of the order 10 k m-1. it was found, that the surface of porous granular ice can recede much slower than of compact ice. when the porosity is 0.75, as relevant for the nuclei of comets, the... | sublimation of porous granular ice in vacuum |
scientific studies using spacecraft radio links, which are shared with communications and navigation functions, have been carried out on almost every solar system exploration mission in the past five decades. they have led to numerous scientific discoveries as well as technological advances. these radio science experim... | future of planetary atmospheric, surface, and interior science using radio and laser links |
the alice far-ultraviolet imaging spectrograph onboard rosetta observed emissions from atomic and molecular species from within the coma of comet 67p/churyumov-gerasimenko during the entire escort phase of the mission from 2014 august to 2016 september. the initial observations showed that emissions of atomic hydrogen ... | fuv spectral signatures of molecules and the evolution of the gaseous coma of comet 67p/churyumov-gerasimenko |
rotational spin-up due to outgassing of comet nuclei has been identified as a possible mechanism for considerable mass-loss and splitting. we report a search for spin changes for three large jupiter-family comets (jfcs): 14p/wolf, 143p/kowal-mrkos, and 162p/siding spring. none of the three comets has detectable period ... | implications of the small spin changes measured for large jupiter-family comet nuclei |
recently acquired bathymetric and high-resolution seismic data from the upper slope of santos basin, southern brazilian margin, reveal a major geomorphological feature in the sw atlantic that is interpreted as a carbonate ridge - the alpha crucis carbonate ridge (accr). the accr is the first megastructure of this type ... | the alpha crucis carbonate ridge (accr): discovery of a giant ring-shaped carbonate complex on the sw atlantic margin |
the rosetta orbiter witnessed several hundred diamagnetic cavity crossings (unmagnetized regions) around comet 67p/churyumov-gerasimenko during its two year survey of the comet. the characteristics of the plasma environment inside these diamagnetic regions are studied using in situ measurements by the rosetta plasma co... | dynamic unmagnetized plasma in the diamagnetic cavity around comet 67p/churyumov-gerasimenko |
kepler's observation of comet tails initiated the research on the radiation pressure of celestial objects and 250 years later they found new incarnation after the maxwell's equations were formulated to describe a plethora of light-matter coupling phenomena. further, quantum mechanics gave birth to the photon drag effec... | photon drag of a bose-einstein condensate |
we provide observational evidence for the existence of large-scale cylindrical (or conic-like) current sheets (ccss) at high heliolatitudes. long-lived ccss were detected by ulysses during its passages over the south solar pole in 1994 and 2007. the characteristic scale of these tornado-like structures is several times... | high-latitude conic current sheets in the solar wind |
the landing of philae, the lander of esa's rosetta-mission, on november 12th 2014 on comet 67p/churyumov-gerasimenko, was planned as a descent with passive landing activating a damper system and anchoring by harpoons at touch-down. the lander was not fixed to the ground at touch-down due to failing harpoons. the lander... | rosetta lander philae - soil strength analysis |
we present the first accurate rate coefficients for the rotational excitation of co by h2o in the kinetic temperature range 5-100 k. the statistical adiabatic channel method (sacm) is combined with a high-level rigid-rotor co-h2o intermolecular potential energy surface. transitions among the first 11 rotational levels ... | the effect of co-h2o collisions in the rotational excitation of cometary co |
we present the first ultraviolet spectra of jupiter trojans. these observations were carried out using the space telescope imaging spectrograph on the hubble space telescope and cover the wavelength range 200-550 nm at low resolution. the targets include objects from both of the trojan color subpopulations (less-red an... | hubble ultraviolet spectroscopy of jupiter trojans |
the origin of planetary rings is one of the least understood processes related to planet formation and evolution. whereas rings seem ubiquitous around giant planets, their great diversity of mass, structure, and composition is a challenge for any formation scenario. satellite destruction by cometary impacts and meteoro... | the origin of planetary ring systems |
we report the discovery of a new small magellanic cloud pulsar wind nebula (pwn) at the edge of the supernova remnant (snr) dem s5. the pulsar powered object has a cometary morphology similar to the galactic pwn analogues psr b1951+32 and `the mouse'. it is travelling supersonically through the interstellar medium. we ... | discovery of a pulsar-powered bow shock nebula in the small magellanic cloud supernova remnant dem s5 |
here, we explore some peculiar orbital features of the recently discovered asteroid a/2017 u1, which is a clear outlier when considering the average value of the eccentricity of known hyperbolic comets. as for the orientation of its orbit in space, the orbital plane of a/2017 u1 seems to be away from any obvious cluste... | pole, pericenter, and nodes of the interstellar minor body a/2017 u1 |
context. results from previous searches for new meteor showers in the combined croatian meteor network and sonotaco meteor databases suggested possible parent bodies for several newly identified showers.aims: we aim to perform an analysis to validate the connection between the identified showers and candidate parent bo... | dynamical modeling validation of parent bodies associated with newly discovered cmn meteor showers |
the nature of 1i/’oumuamua (henceforth, 1i), the first interstellar object (iso) known to pass through the solar system, remains mysterious. feng & jones noted that the incoming 1i velocity vector “at infinity” ({v}∞ ) is close to the motion of the pleiades dynamical stream (or local association), and suggested tha... | high-drag interstellar objects and galactic dynamical streams |
we critically examine what hyperactivity on a comet entails, fully develop the a'hearn model for hyperactivity based on the analyses of data collected for the deep impact encounter of comet 103p/hartley 2, describe manifestations of hyperactivity suggested on many, if not all, comets, and give implications of hyperacti... | all comets are somewhat hyperactive and the implications thereof |
we present visible spectroscopic and albedo data of the 2.3 gyr old themis family and the <10 myr old beagle sub-family. the slope and albedo variations between these two families indicate c-complex asteroids become redder and darker in response to space weathering. our observations of themis family members confirm ... | space weathering trends among carbonaceous asteroids |
methane is the second most important greenhouse gas in terms of anthropogenic radiative forcing. since pre-industrial times, the globally averaged dry mole fraction of methane in the atmosphere has increased considerably. emissions from coal mining are one of the primary anthropogenic methane sources. however, our know... | hindcasting and forecasting of regional methane from coal mine emissions in the upper silesian coal basin using the online nested global regional chemistry-climate model meco(n) (messy v2.53) |
we present the code catalogue, the new cometary catalogue containing data for almost 300 long-period comets that were discovered before 2018. this is the first catalogue containing cometary orbits in the five stages of their dynamical evolution and covering three successive passages through the perihelion, with the exc... | the catalogue of cometary orbits and their dynamical evolution |
debris disks are the dust disks found around ∼20% of nearby main sequence stars in far-ir surveys. they can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on circumstellar disk evolution and the outcome of planet formation. the debris disk populat... | debris disks: probing planet formation |
we present the experimental phase functions of three types of millimeter-sized dust grains consisting of enstatite, quartz, and volcanic material from mount etna, respectively. the three grains present similar sizes but different absorbing properties. the measurements are performed at 527 nm covering the scattering ang... | experimental phase functions of millimeter-sized cosmic dust grains |
the near-earth object wide-field infrared survey explorer (neowise) spacecraft has been conducting a two-band thermal infrared survey to detect and characterize asteroids and comets since its reactivation in 2013 december. using the observations collected during the fourth and fifth years of the survey, our automated p... | asteroid diameters and albedos from neowise reactivation mission years 4 and 5 |
aims: we present a multi-instrumental, multidecadal analysis of the activity of the eta-aquariid and orionid meteor showers for the purpose of constraining models of 1p/halley's meteoroid streams.methods: the interannual variability of the showers' peak activity and period of duration is investigated through the compil... | activity of the eta-aquariid and orionid meteor showers |
we apply the analytical disturbing function for arbitrary inclination derived in our previous work to characterize resonant width and libration of mean motion resonances at arbitrary inclination obtained from direct numerical simulations of the three-body problem. we examine the 2:1 and 3:1 inner jupiter and 1:2 and 1:... | resonance libration and width at arbitrary inclination |
aims: we investigated wosret, a region located on the small lobe of the 67p/churyumov-gerasimenko comet subject to strong heating during the perihelion passage. this region includes the two last landing sites of the philae lander as well as, notably the final one, abydos, where the lander performed most of its measurem... | small lobe of comet 67p: characterization of the wosret region with rosetta-osiris |
the cosmic dust particles found in space are mainly porous aggregates of smaller grains. theoretically, these aggregates are replicated using fractal geometry, assuming a cluster of spheres. although the light scattering response of cosmic dust aggregates has been thoroughly studied using clusters of spherical grains i... | a comprehensive model of morphologically realistic cosmic dust particles: an application to mimic the unusual polarization properties of the interstellar comet 2i/borisov |
this paper introduces an algorithm to perform optimal reorientation of a spacecraft during a high speed flyby mission that maximizes the time a certain target is kept within the field of view of scientific instruments. the method directly handles the nonlinear dynamics of the spacecraft, sun exclusion constraint, torqu... | optimal science-time reorientation policy for the comet interceptor flyby via sequential convex programming |
we study the long-term radial transport of micron to millimeter-size grains in protostellar disks (psds) based on diffusion and viscosity coefficients measured from 3d global stratified-disk simulations with a lagrangian hydrodynamic method. while gas drag tends to transport dust species radially inwards, stochastic di... | turbulent transport of dust particles in protostellar disks: the effect of upstream diffusion |
context. a cornucopia of rosetta and ground-based observational data sheds light on the evolution of the characteristics of dust particles from comet 67p/churyumov-gerasimenko (hereafter 67p) with seasons, implying the different dust environments in the source regions on the surface of the comet.aims: we aim to constra... | vlt spectropolarimetry of comet 67p: dust environment around the end of its intense southern summer |
in this work, we introduce a comet dust model that incorporates multiple dust morphologies along with inhomogeneous mixture of silicate minerals and carbonaceous materials under power-law size distribution, to replicate the standard polarization-phase curve observed in several comets in the narrow-band continuum. follo... | modelling heterogeneous dust particles: an application to cometary polarization |
we announce the discovery of activity, in the form of a distinct cometary tail, emerging from main-belt asteroid 2015 va108. activity was first identified by volunteers of the citizen science project active asteroids (a nasa partner). we uncovered one additional image from the same observing run which also unambiguousl... | new active asteroid 2015 va108: a citizen science discovery |
interstellar objects (isos) are fascinating and under-explored celestial objects, providing physical laboratories to understand the formation of our solar system and probe the composition and properties of material formed in exoplanetary systems. this paper will discuss the accessibility of and mission design to isos w... | interstellar object accessibility and mission design |
formamide is a potentially important molecule in the context of pre-biotic chemistry, since reactions involving it can lead to precursors of genetic and metabolic molecules. being abundant in cometary material and in star-forming regions, the formation and destruction routes of interstellar formamide have been the focu... | dissociative electron recombination of nh2choh+ and implications for interstellar formamide abundance |
we report that a major outburst of comet 29p/schwassmann-wachmann 1 was detected by using the images acquired with the slt (16" ritchey-chretien telescope) at lulin observatory. | another major outburst of comet 29p/schwassmann-wachmann 1 |
the paper considers the free molecular flow of gas through the dusty porous surface layer of a comet nucleus. the study is based on computer models of generation of a porous medium and knudsen gas diffusion. we consider various types of homogeneous and heterogeneous layers constructed from nonintersecting spheres, incl... | transport characteristics of the near-surface layer of the nucleus of comet 67p/churyumov-gerasimenko |
consideration is given to the estimates for the strength of the consolidated material forming the bulk of the nucleus of comet 67p churyumov-gerasimenko and those for the strength of the surface material overlying the consolidated material at the sites of the first and last contact of the philae lander with the nucleus... | estimating the strength of the nucleus material of comet 67p churyumov-gerasimenko |
astrophysical shocks are commonly revealed by the non-thermal emission of energetic electrons accelerated in situ1-3. strong shocks are expected to accelerate particles to very high energies4-6; however, they require a source of particles with velocities fast enough to permit multiple shock crossings. while the resulti... | electron acceleration by wave turbulence in a magnetized plasma |
aims: we derive the size-frequency distribution of boulders on comet 103p/hartley 2, which are computed from the images taken by the deep impact/hri-v imaging system. we indicate the possible physical processes that lead to these boulder size distributions.methods: we used images acquired by the high resolution imager-... | size-frequency distribution of boulders ≥10 m on comet 103p/hartley 2 |
the structure and composition of cometary constituents, down to their microscopic scale, are critical witnesses of the processes and ingredients that drove the formation and evolution of planetary bodies toward their present diversity. on board rosetta’s lander philae, the comet infrared and visible analyser (civa) exp... | 67p/churyumov-gerasimenko surface properties as derived from civa panoramic images |
cosmic dust is a polydisperse mixture of irregular, often aggregated, particles. previous attempts have tried to simulate polarimetric properties of this dust using aggregate dust models, but it has not been possible to consider particle sizes larger than a couple of microns due to limitations of computer memory and pr... | polarization of cosmic dust simulated with the rough spheroid model |
the comet assay is a sensitive method for the evaluation of dna damages and dna repair capacity at single‑cell level. allium cepa is a well‑established plant model for toxicological studies. the aim of this scoping review was to investigate the recent application of the comet assay in allium cepa root cells to assess t... | a scoping review of recent advances in the application of comet assay to allium cepa roots |
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... | rosetta following a living comet |
disinfection with performic acid (pfa) represents an emerging technology in wastewater treatment. many recent studies indicate its effectiveness and suitability as a disinfectant for different applications; several have demonstrated its reliability as an alternative to chlorine for disinfecting secondary effluents from... | evaluation of cytotoxicity, genotoxicity, and apoptosis of wastewater before and after disinfection with performic acid |
the chondritic-porous subset of interplanetary dust particles (cp-idps) are thought to have a cometary origin. since the cp-idps are anhydrous and unaltered by aqueous processes that are common to chondritic organic matter (om), they represent the most pristine material of the solar system. however, the study of idp om... | organics preserved in anhydrous interplanetary dust particles: pristine or not? |
we have investigated through simulation the electrostatic charging of the nucleus of comet 67p/churyumov-gerasimenko during periods of weak outgassing activity. specifically, we have modeled the surface potential and electric field at the surface of the nucleus during the initial rosetta rendezvous at 3.5 au and the re... | surface charging and electrostatic dust acceleration at the nucleus of comet 67p during periods of low activity |
numerical simulations show that impactors can penetrate europa's ice, creating conduits to the underlying ocean. breaching becomes inevitable when transient cavity depth exceeds 90% of ice thickness. results indicate that a 0.5 km comet would penetrate 5 km ice, and a 5 km comet could breach 40 km ice. thinner ice woul... | impact breaching of europa's ice: constraints from numerical modeling |
analyzing data from the ion composition analyzer on board the rosetta spacecraft, we studied a flow pattern of accelerated cometary ions (40-80 ev) inside and outside the diamagnetic cavity of comet 67p/churyumov-gerasimenko (67p). we found that the accelerated ions are intermittently observed and are ten times more fr... | flow pattern of accelerated cometary ions inside and outside the diamagnetic cavity of comet 67p/churyumov-gerasimenko |
the topological aspects of fluid flows have long been fascinating subjects in the study of the physics of fluids. in this study, the topology of the second-order boltzmann-curtiss constitutive model beyond the conventional navier-stokes-fourier equations and stokes's hypothesis was investigated. in the case of velocity... | topology of the second-order constitutive model based on the boltzmann-curtiss kinetic equation for diatomic and polyatomic gases |
the spectra emitted by highly charged ions, which are abundant in laboratory plasma and stellar systems, cover a wide range of wavelengths from near-infrared to x-rays. measurements on such spectral lines can provide plasma information such as the electron temperature, electron/ion density, chemical composition, and th... | k-x-ray emission of 1.5-20 kev/q oq+ (q = 3, 5, 6) and nq+ (q = 3, 5) ions impinging on nickel surface |
the response of the mutual impedance probe rpc-mip on board rosetta orbiter electrostatically modeled considering an unmagnetized and collisionless plasma with two maxwellian electron populations. a vacuum sheath surrounding the probe was considered in our model in order to take the ion sheath into account that is loca... | rpc-mip observations at comet 67p/churyumov-gerasimenko explained by a model including a sheath and two populations of electrons |
in this paper, we present a study of the dynamical effects of the galaxy on the external region of the oort cloud. the aims of this paper are: (i) to determine an outer limit for the oort cloud; and (ii) to analyse the dynamical behaviour of the most external objects of the oort cloud and how they are ejected from the ... | stability in the most external region of the oort cloud: evolution of the ejected comets |
a number of studies have assessed or modeled the distribution of the radionuclides released by the accident at the fukushima-daiichi nuclear power plant (fdnpp). few studies however have investigated its consequences for the local biota. we tested whether exposure of barn swallow (hirundo rustica) nestlings to low dose... | abundance and genetic damage of barn swallows from fukushima |
water ices are a common component of cold space environments, including molecular and protostellar clouds, and the frozen surfaces of moons, planets, and comets. when exposed to ionizing and/or thermal processing, they become a nursery for new molecular species and are also responsible for their desorption to the gas-p... | chemical evolution of electron-bombarded crystalline water ices at different temperatures using the procoda code |
we analyzed images of comet 49p/arend-rigaux on 33 nights between 2012 january and may and obtained r-band lightcurves of the nucleus. through usual phasing of the data, we found a double-peaked lightcurve having a synodic rotation period of 13.450 ± 0.005 hr. similarly, phase dispersion minimization and the lomb-scarg... | the rotation and other properties of comet 49p/arend-rigaux, 1984-2012 |
this paper is a review of molecules with internal rotors detected or tentatively detected with upper limits in the interstellar medium. internal rotor molecules containing one or two methyl groups are present at each of the different phases leading to stellar and planetary formation, from the molecular clouds to the st... | spectroscopy of interstellar internal rotors: an important tool for investigating interstellar chemistry |
context. the first 1000 km of the ion tail of comet 67p/churyumov-gerasimenko were explored by the european rosetta spacecraft, 2.7 au away from the sun.aims: we characterised the dynamics of both the solar wind and the cometary ions on the night-side of the comet's atmosphere.methods: we analysed in situ ion and magne... | the root of a comet tail: rosetta ion observations at comet 67p/churyumov-gerasimenko |
radar-bright deposits at the poles of mercury are located in permanently shadowed regions, which provide thermally stable environments for hosting and retaining water ice on the surface or in the near subsurface for geologic timescales. while the areal distribution of these radar-bright deposits is well characterized, ... | constraining the thickness of polar ice deposits on mercury using the mercury laser altimeter and small craters in permanently shadowed regions |
tin order to improve our current knowledge on the budgets of the two most important anthropogenic greenhouse gases, co2 and ch4, an airborne mission on board the german research aircraft halo in coordination with two smaller cessna aircraft is going to be conducted in april/may 2017. the goal of comet is to combine a s... | comet: an airborne mission to simultaneously measure co2 and ch4 using lidar, passive remote sensing, and in-situ techniques |
plumes produced by the impacts of asteroids and comets consist of rock vapor and heated air. they emit visible light, ultraviolet, and infrared radiation, which can greatly affect the environment. we have carried out numerical simulations of the impacts of stony and cometary bodies with a diameter of 0.3, 1, and 3 km, ... | thermal radiation from impact plumes |
long term evolution of an initial set of 107 oort cloud comets is performed for the age of the solar system taking into account the action of passing stars using 10 different sequences of stellar encounters, galactic tides and the gravity of the giant planets. the initial conditions refer to a disk-shaped oort cloud pr... | on the present shape of the oort cloud and the flux of ;new; comets |
the recent successes of the european rosetta mission have shown the possibility of a close observation with one of the most evasive celestial bodies in the solar system, the comets, and the practical feasibility of a comet rendezvous to obtain detailed information and in situ measurements. this paper discusses a prelim... | electric sail option for cometary rendezvous |
a theoretical study on the ultra-low frequency small but finite amplitude solitary waves has been carried out in an electron depleted magnetized nonthermal dusty plasma consisting of both polarity (positively charged as well as negatively charged) inertial massive dust particles and nonextensive q distributed ions. the... | low frequency nonlinear waves in electron depleted magnetized nonthermal plasmas |
we report a theoretical study of the infrared (ir) vibrational spectra of ch3 + and its deuterated isotopologues. we also report exothermicities for reactions of these species with hd and d2. the calculations are performed using the two-layer lanzcos algorithm with an exact full-dimensional molecular hamiltonian, based... | infrared vibrational spectra of ch3 + and its deuterated isotopologues |
water worlds are water-rich (>1 wt% h2o) exoplanets. the classical models of water worlds considered layered structures determined by the phase boundaries of pure water. however, water worlds are likely to possess comet-like compositions, with between ∼3 and 30 mol% co2 relative to water. in this study, we build an ... | internal structure and co2 reservoirs of habitable water worlds |
context. cometary meteoroid trails exist in the vicinity of comets, forming a fine structure of the interplanetary dust cloud. the trails consist predominantly of the largest cometary particles (with sizes of approximately 0.1 mm-1 cm), which are ejected at low speeds and remain very close to the comet orbit for severa... | helios spacecraft data revisited: detection of cometary meteoroid trails by following in situ dust impacts |
the atacama large millimeter/submillimeter array (alma) is a powerful tool for high-resolution mapping of comets, but the main interferometer (comprised of 50 × 12 m antennas) is insensitive to the largest coma scales due to a lack of very short baselines. in this letter, we present a new technique employing alma autoc... | alma autocorrelation spectroscopy of comets: the hcn/h13cn ratio in c/2012 s1 (ison) |
the effect of the radial drift rate on mean motion resonance capture is studied for prograde, polar and retrograde orbits. we employ the numerical framework of our earlier exploration of resonance capture at arbitrary inclination. randomly constructed samples of massless particles are set to migrate radially from outsi... | resonance capture at arbitrary inclination - ii. effect of the radial drift rate |
this paper discusses the influence of light pollution of the night sky on the conditions of visibility of astronomical objects such as planets, stars and comets. this phenomenon has a huge impact on the observability of astronomical objects, especially in cities, where the brightness of the sky makes it difficult or ev... | impact of light pollution on the visibility of astronomical objects in medium-sized cities in central europe on the example of the city of rzeszów, poland |
the compositional and morphological evolution of minor bodies in the solar system is primarily driven by the evolution of their heliocentric distances, as the level of incident solar radiation regulates cometary activity. we investigate the dynamical transfer of centaurs into the inner solar system, facilitated by mean... | a sublime opportunity: the dynamics of transitioning cometary bodies and the feasibility of in situ observations of the evolution of their activity |
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