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aims: the aim of this work is to characterise hcn and ch3oh emission from recent comets.methods: we used the onsala 20-m telescope to search for millimetre transitions of hcn towards a sample of 11 recent and mostly bright comets in the period from december 2016 to november 2019. also, ch3oh was searched for in two com... | emission from hcn and ch3oh in comets. onsala 20-m observations and radiative transfer modelling |
the national toxicology program tested two common radiofrequency radiation (rfr) modulations emitted by cellular telephones in a 2‑year rodent cancer bioassay that included interim assessments of additional animals for genotoxicity endpoints. male and female hsd:sprague dawley sd rats and b6c3f1/n mice were exposed fro... | evaluation of the genotoxicity of cell phone radiofrequency radiation in male and female rats and mice following subchronic exposure |
partially ionized plasmas (pip) are essential constituents of many astrophysical environments, including the solar atmosphere, the interstellar medium, molecular clouds, accretion disks, planet ionospheres, cometary tails, etc., where the ionization degree may vary from very weak ionization to almost full ionization. t... | theory of fluid instabilities in partially ionized plasmas: an overview |
in 2015 may, the southern hemisphere of comet 67p/churyumov-gerasimenko became visible by the osiris cameras on-board the rosetta spacecraft. the resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the northern hemisphere. previous works show that fine pa... | geomorphological mapping of comet 67p/churyumov-gerasimenko's southern hemisphere |
while the structural complexity of cometary comae is already recognizable from telescopic observations1, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality2,3. the dust coma displays jet-like features of enhanced brightness superposed on a diffuse bac... | coma morphology of comet 67p controlled by insolation over irregular nucleus |
the highly varying plasma environment around comet 67p/churyumov-gerasimenko inspired an upgrade of the ion mass spectrometer (rosetta plasma consortium ion composition analyzer) with new operation modes, to enable high time resolution measurements of cometary ions. two modes were implemented, one having a 4 s time res... | investigating short-time-scale variations in cometary ions around comet 67p |
the aim of this study was to investigate preservation of biomolecular structures, particularly dna, in freeze-dried fibroblasts, after loading with trehalose via freezing-induced uptake. cells were freeze-dried with trehalose alone or in a mixture of albumin and trehalose. albumin was added to increase the glass transi... | freeze-drying of mammalian cells using trehalose: preservation of dna integrity |
the osiris camera onboard rosetta measured the phase function of both the coma dust and the nucleus. the two functions have a very different slope versus the phase angle. here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. this... | the phase function and density of the dust observed at comet 67p/churyumov-gerasimenko |
context. the mutual impedance probe (mip) of the rosetta plasma consortium (rpc) onboard the rosetta orbiter which was in operation for more than two years, between august 2014 and september 2016 to monitor the electron density in the cometary ionosphere of 67p/churyumov-gerasimenko. based on the resonance principle of... | observations of a mix of cold and warm electrons by rpc-mip at 67p/churyumov-gerasimenko |
radar observations of mercury and the mercury surface, space environment, geochemistry, and ranging (messenger) spacecraft data indicate the probable existence of water ice in the permanently shadowed polar regions. generally, water is accepted to be of exogenous origin through delivery via comets and meteoritic impact... | a new in situ quasi-continuous solar-wind source of molecular water on mercury |
in-situ measurements of individual dust grain parameters in the immediate vicinity of a cometary nucleus are being carried by the rosetta spacecraft at comet 67p/churyumov-gerasimenko. for the interpretations of these observational data, a model of dust grain motion as realistic as possible is requested. in particular,... | dynamics of aspherical dust grains in a cometary atmosphere: i. axially symmetric grains in a spherically symmetric atmosphere |
the galaxy cluster abell 3376 is a nearby (\bar{z}=0.046) dissociative merging cluster surrounded by two prominent radio relics and showing an x-ray comet-like morphology. the merger system is comprised of the subclusters a3376w and a3376e. based on new deep multiwavelength large-field images and published redshifts, w... | weak lensing and spectroscopic analysis of the nearby dissociative merging galaxy cluster abell 3376 |
the landing of the rosetta-mission lander philae on november 12th 2014 on comet 67 p/churyumov-gerasimenko was planned as a descent with passive landing and anchoring by harpoons at touch-down. actually the lander was not fixed at touch-down to the ground due to failing harpoons. the lander internal damper was actuated... | rosetta lander philae: touch-down reconstruction |
volatile production rates, relative abundances, rotational temperatures, and spatial distributions in the coma were measured in c/2012 s1 (ison) using long-slit high-dispersion (λ/δλ ∼ 2.5 × 104) infrared spectroscopy as part of a worldwide observing campaign. spectra were obtained on ut 2013 october 26 and 28 with nir... | the compositional evolution of c/2012 s1 (ison) from ground-based high-resolution infrared spectroscopy as part of a worldwide observing campaign |
the fugin co survey revealed the three-dimensional structure of a galactic shock wave in the tangential direction of the 4 kpc molecular arm. the shock front is located at g30.5+00.0 + 95 km s-1 on the upstream (lower longitude) side of the star-forming complex w 43 (g30.8-0.03), and comprises a molecular bow shock (mb... | forest unbiased galactic plane imaging survey with the nobeyama 45 m telescope (fugin). iv. galactic shock wave and molecular bow shock in the 4 kpc arm of the galaxy |
comets considered to be pristine objects contain key information about the early formation of the solar system. their volatile components can provide clues about the origin and evolution of gases and ices in the comets. measurements with rosina/rtof at 67p/churyumov-gerasimenko have now allowed, for the first time, a d... | high-time resolution in-situ investigation of major cometary volatiles around 67p/c-g at 3.1 - 2.3 au measured with rosina-rtof |
the cyano radical (cn) is one of the most frequently remotely observed species in space, and is also often observed in comets. data for the inner coma of comet 67p/churyumov-gerasimenko collected by the high-resolution double focusing mass spectrometer (dfms) on board the rosetta orbiter revealed an unexpected chemical... | cyanogen, cyanoacetylene, and acetonitrile in comet 67p and their relation to the cyano radical |
pulsars traveling at supersonic speeds are often accompanied by cometary bow shocks seen in hα. we report on the first detection of a pulsar bow shock in the far-ultraviolet (fuv). we detected it in fuv images of the nearest millisecond pulsar j0437-4715 obtained with the hubble space telescope. the images reveal a bow... | first detection of a pulsar bow shock nebula in far-uv: psr j0437-4715 |
studies suggest that the pollution of white dwarf (wd) atmospheres arises from the accretion of minor planets, but the exact properties of polluting material, and in particular the evidence for water in some cases are not yet understood. several previous works studied the possibility of water surviving inside minor pla... | post-main-sequence evolution of icy minor planets. iii. water retention in dwarf planets and exomoons and implications for white dwarf pollution |
we present the results of a molecular survey of comet 67p/churyumov-gerasimenko undertaken with the institut de radioastronomie millimétrique (iram) 30-m radio telescope in november-december 2021, when it had its most favourable apparition in decades. observations at iram 30-m during the 12-16 november period covered 8... | coma composition of comet 67p/churyumov-gerasimenko from radio-wave spectroscopy |
motion of many comets is affected by non-gravitational forces caused by outgassing from their surfaces. outgassing also produces reactive torques resulting in cometary spin evolution. we propose that the two processes are correlated and show that the change of cometary spin rate over its heliocentric orbit scales linea... | non-gravitational forces and spin evolution of comets |
the encounter of the meteoric material from 73p/schmassmann-wachmann 3 produced during the comet's 1995 outburst in may 2022 provides a rare and valuable opportunity to understand a fragmenting comet. here, we explore various ejection configurations and their impact on the meteor outburst detected in the early hours of... | the 2022 encounter of the outburst material from comet 73p/schwassmann-wachmann 3 |
we investigate the role of secondary electron and ion emission from impact of gas molecules on the cassini langmuir probe (rpws-lp or lp) measurements in the ionosphere of saturn. we add a model of the emission currents, based on laboratory measurements and data from comet 1p/halley, to the equations used to derive pla... | implications from secondary emission from neutral impact on cassini plasma and dust measurements |
context. on 12 november 2014, the european mission rosetta delivered the philae lander on the nucleus of comet 67p/churyumov-gerasimenko (67p). after the first touchdown, the lander bounced three times before finally landing at a site named abydos.aims: we provide a morphologically detailed analysis of the abydos landi... | characterization of the abydos region through osiris high-resolution images in support of civa measurements |
context. the giotto and rosetta missions gave us the unique opportunity of probing the close environment of cometary ionospheres of 1p/halley (1p) and 67p/churyumov-gerasimenko (67p). the plasma conditions encountered at these two comets were very different from each other, which mainly stem from the different heliocen... | comparative study of photo-produced ionosphere in the close environment of comets |
we measure the photometric color in the inner coma of comet 29p/schwassmann-wachmann 1 on nine nights in august and october, 2018. we see variations in the color slope from s′ = (19.72 ± 1.72)% per 0 . 1 μm to s′ = -(6.88 ± 1.72)% per 0 . 1 μm . the blue color is accompanied with increasing brightness suggesting that i... | color variations of comet 29p/schwassmann-wachmann 1 in 2018 |
the relative fractions of fe in metal, sulfide, or oxide—the fe oxidation state—in the interstellar medium (ism) can provide constraints on the processes that operated on material in the protosolar disk. we used synchrotron-based x-ray absorption spectra of three mineral standards and two kinds of primitive extraterres... | measurement of the oxidation state of fe in the ism using x-ray absorption spectroscopy |
primitive solar system materials, such as certain types of meteorites, interplanetary dust particles and cometary matter, contain small quantities of refractory dust grains that are older than our solar system. these `presolar grains' condensed in the winds of evolved stars and in the ejecta of stellar explosions, and ... | the stardust abundance in the local interstellar cloud at the birth of the solar system |
from the operation of the mupus thermal probe spohn et al. (2015) concluded that the material of the nucleus of 67p/churyumov-gerasimenko is likely to have a high strength, at least locally at the philae landing site. in this work we consider the derived strength of the material in order to constrain its granulation. f... | comet 67p/churyumov-gerasimenko: hardening of the sub-surface layer |
{\tilde{x}}2a\prime\prime hss has yet to be observed in the gas phase in the interstellar medium (ism). hss has been observed in cometary material and in high abundance. however, its agglomeration to such bodies or dispersal from them has not been observed. similarly, hso and hos have not been observed in the ism, eith... | on the detectability of the x 2a" hss, hso, and hos radicals in the interstellar medium |
aims: the morphology of cometary surfaces can provide important information to constrain the composition and evolution of comets. in this work, we investigate the sublimation behavior of comet analog materials and how the sample composition affects the evolution of morphological features in laboratory experiments. in o... | sublimation of ice-dust mixtures in cooled vacuum environments to reproduce cometary morphologies |
the daytime arietid meteor shower is active from mid-may to late june and is amongst the strongest of the annual meteor showers, comparable in activity and duration to the perseids and the geminids. due to the daytime nature of the shower, the arietids have mostly been constrained by radar studies. the arietids exhibit... | the age and the probable parent body of the daytime arietid meteor shower |
spectral parameters measured by the rosetta/virtis imaging spectrometer on the nucleus of comet 67p/churyumov-gerasimenko were studied as a function of incidence, emission and phase angles. a statistical analysis was undertaken for a number of spectral parameters: reflectance at seven wavelengths (0.55, 0.75, 1.2, 1.7,... | photometric behaviour of 67p/churyumov-gerasimenko and analysis of its pre-perihelion diurnal variations |
submillimeter/far-ir spectroscopy was used to detect and quantify organic molecules sublimated after the ultraviolet photolysis (at 12 k) and warm-up (up to 300 k) of a methanol (ch3oh) ice sample. eleven sublimated photoproducts were uniquely identified: carbon monoxide (co), formaldehyde (h2co), ketene (c2h2o), aceta... | sublimation of laboratory ices millimeter/submillimeter experiment (sublime): structure-specific identifications of products from uv-photolyzed methanol ice |
explanation of the observed gas activity based on the parameters of the comet's nucleus is not an obvious matter. solutions based on certain thermal models can be obtained, but the use of arbitrary values for poorly known model parameters is always required. in this work, we carry out a study of the dependence of gas a... | sensitivity of modelled cometary gas production on the properties of the surface layer of the nucleus |
aims: we theoretically investigated the dimerization of methanimine, ch2=nh, a process that has been invoked to explain the formation of haze in the atmosphere of titan and nitrogen organic compounds in interstellar/cometary ice analogs.methods: we used density functional theory to characterize the minima and transitio... | dimerization of methanimine and its charged species in the atmosphere of titan and interstellar/cometary ice analogs |
we present a global geomorphological map of comet 67p/churyumov-gerasimenko (67p/c-g) using data acquired by the rosetta orbiter's osiris narrow angle camera. the images used in our study were acquired between 2014 august and 2015 may, before 67p/c-g passed through perihelion. imagery of the southern hemisphere was inc... | geomorphology of comet 67p/churyumov-gerasimenko |
downward fluxes of fe and na, measured near the mesopause with the university of colorado lidars near boulder, and a chemical ablation model developed at the university of leeds, are used to constrain the velocity/mass distribution of the meteoroids entering the atmosphere and to derive an improved estimate for the glo... | measurements of the vertical fluxes of atomic fe and na at the mesopause: implications for the velocity of cosmic dust entering the atmosphere |
hyperactive comets have high water production rates, with inferred sublimation areas of order the surface area of the nucleus. comets 46p/wirtanen and 103p/hartley 2 are two examples of this cometary class. based on observations of comet hartley 2 by the deep impact spacecraft, hyperactivity appears to be caused by the... | nondetection of water-ice grains in the coma of comet 46p/wirtanen and implications for hyperactivity |
aims: we investigate the influence of three basic factors on water production rate as a function of heliocentric distance: nucleus shape, the spin axis orientation, and the distribution of activity on a comet's surface.methods: we used a basic water sublimation model driven by solar insolation to derive total productio... | interpretation of heliocentric water production rates of comets |
aims: we present a study of the meteor complex of the short-period comet 2p/encke.methods: for five perihelion passages of the parent comet in the past, we modeled the associated theoretical stream. specifically, each of our models corresponds to a part of the stream characterized with a single value of the evolutionar... | meteoroid-stream complex originating from comet 2p/encke |
context. thanks to our expanding knowledge of the galactic and stellar neighborhood of the solar system, modern long-period comet motion studies must take into account both stellar perturbations and the overall galactic potential.aims: our aim is to propose algorithms and methods that aid in performing numerical integr... | galactic and stellar perturbations of long-period comet motion. practical considerations |
we consider the stochastic heat equation on $\mathbb r^d$ with multiplicative space-time white noise noise smoothed in space. for $d\geq 3$ and small noise intensity, the solution is known to converge to a strictly positive random variable as the smoothing parameter vanishes. in this regime, we study the rate of conver... | fluctuation and rate of convergence for the stochastic heat equation in weak disorder |
comet interceptor is an esa f-class mission expected to launch in 2028 on the same launcher as esa's ariel mission. comet interceptor's science payload consists of three spacecraft, a primary spacecraft that will carry two smaller probes to be released at the target. the three spacecraft will fly-by the target along di... | potential backup targets for comet interceptor |
in its 16 years of scientific measurements, the spitzer space telescope performed ground-breaking and key infrared measurements of solar system objects near and far. targets ranged from the smallest planetesimals to the giant planets; spitzer helped us to reshape our understanding of these objects while also laying the... | spitzer's solar system studies of comets, centaurs and kuiper belt objects |
the plasma environment near comet 67p/churyumov-gerasimenko (67p/cg) is dynamically affected by various factors, including the incident solar wind and outgassing from the nucleus. the rosetta spacecraft magnetometer (mag) instrument observations near perihelion showed crossing events into a magnetic field-free region a... | plasma environment around comet 67p/churyumov-gerasimenko at perihelion: model comparison with rosetta data |
models of the solar system evolution show that almost all the primitive material leftover from the formation of the planets was ejected to the interstellar space as a result of dynamical instabilities. accordingly, minor bodies should also be ejected from other planetary systems and should be abundant in the interstell... | tumbling motion of 1i/'oumuamua reveals body's violent past |
context. the origin of water in the stratospheres of giant planets has been an outstanding question ever since its first detection by the infrared space observatory some 20 years ago. water can originate from interplanetary dust particles, icy rings and satellites, and large comet impacts. analyses of herschel space ob... | herschel map of saturn's stratospheric water, delivered by the plumes of enceladus |
to test a technique to be used on the white-light imager onboard the recently launched parker solar probe mission, we performed a numerical differentiation of the brightness profiles along the photometric axis of the f-corona models that are derived from stereo ahead sun earth connection heliospheric investigation obse... | evidence for a circumsolar dust ring near mercury’s orbit |
we measure the degree of linear polarization of comet 46p/wirtanen during two months, embracing the perihelion passage in 2018 december with phase angles ranging from α = 18.1° to 46.4°. the polarimetric response pq obtained resembles what was previously found in comet c/1975 v1 (west). this suggests 46p/wirtanen belon... | monitoring polarization in comet 46p/wirtanen |
pillars and globules are the best examples of the impact of the radiation and wind from massive stars on the surrounding interstellar medium. we mapped the g287.84-0.82 cometary globule (with the treasure chest cluster embedded in it) in the south pillars region of carina (i) in [c ii], 63 μm [o i], and co(11-10) using... | opening the treasure chest in carina |
we review the development of dust science from the first ground-based astronomical observations of dust in space to compositional analysis of individual dust particles and their source objects. a multitude of observational techniques is available for the scientific study of space dust: from meteors and interplanetary d... | the dawn of dust astronomy |
a 2000-2017 set of long-period comets with high-quality orbits of perihelion distance <1 au is used to show that the objects that perish shortly before perihelion are nearly exclusively the oort cloud comets, especially those with perihelia within 0.6 au of the sun, intrinsically fainter, and dust poor. their propen... | 1i/`oumuamua and the problem of survival of oort cloud comets near the sun |
context. the large and vertically non-uniform abundance of co in neptune's atmosphere has been interpreted as the result of past cometary impact(s), either single or distributed in size and time, which could also be at the origin of neptune's hcn.aims: we aim to provide observational support for this scenario by search... | detection of cs in neptune's atmosphere from alma observations |
in this work, we present the results of an observational study of 2i/borisov carried out with the 10.4-m gran telescopio canarias (gtc) and the 3.6-m telescopio nazionale galileo (tng), both telescopes located at the roque de los muchachos observatory, in the island of la palma (spain). the study includes images in the... | visible and near-infrared observations of interstellar comet 2i/borisov with the 10.4-m gtc and the 3.6-m tng telescopes |
a new experimental setup, interstellar ice-dust experiment (inside), was designed for studying cosmic grain analogs represented by ice-coated carbon- and silicate-based dust grains. with the new instrument, we can simulate the physical and chemical conditions prevailing in interstellar and circumstellar environments. t... | photodesorption of water ice from dust grains and thermal desorption of cometary ices studied by the inside experiment |
we present the results of millimetre-wave spectroscopic and continuum observations of the comet c/2020 f3 (neowise) undertaken with the institut de radioastronomie millimétrique (iram) 30-m and the northern extended millimeter array (noema) telescopes on 22, 25-27 july, and 7 august 2020. production rates of hcn, hnc, ... | observations of comet c/2020 f3 (neowise) with iram telescopes |
we review the recent observations of protoplanetary disks together with relevant theoretical studies with an emphasis on the evolution of volatiles. in the last several years atacama large millimeter/submillimeter array (alma) provided evidence of grain growth, gas-dust decoupling, and sub-structures such as rings and ... | the physical and chemical processes in protoplanetary disks: constraints on the composition of comets |
discovery of nine populations in a set of 193 select soho kreutz sungrazers (sekanina 2021) is confirmed for the first time via a histogram of the true longitudes of the ascending node, constructed for a revised set of 220 select sungrazers imaged exclusively by the soho's c2 coronagraph. marsden's orbits are approxima... | populations of the kreutz sungrazer system in a soho database |
using visible multiobject spectrograph (vimos)-integral field unit (ifu) observations, we study the interstellar medium (ism) of two star-forming dwarf galaxies, um 461 and mrk 600. our aim was to search for the existence of metallicity inhomogeneities that might arise from infall of nearly pristine gas feeding ongoing... | detecting metal-poor gas accretion in the star-forming dwarf galaxies um 461 and mrk 600 |
context. the study of distant comets, which are active at large heliocentric distances, is important for a better understanding of their physical properties and mechanisms of long-lasting activity.aims: we analyzed the dust environment of the distant comet c/2014 a4 (sonear), with a perihelion distance near 4.1 au, usi... | photometry, spectroscopy, and polarimetry of distant comet c/2014 a4 (sonear) |
the mineralogy of comet 81p/wild 2 particles, collected in aerogel by the stardust mission, has been determined using synchrotron fe-k x-ray absorption spectroscopy with in situ transmission xrd and x-ray fluorescence, plus complementary microraman analyses. our investigation focuses on the terminal grains of eight sta... | magnetite in comet wild 2: evidence for parent body aqueous alteration |
chondrules are sub-millimetre spherical metal-sulphide-silicate objects which formed from the solar protoplanetary disk material, and as such provide an important record of the chronology and conditions of the solar system in pre-planetary times. chondrules are a major constituent of chondritic meteorites; however, des... | chondrules: records of protoplanetary disk processes |
copper oxide nanoparticles (cuo nps) are known to exhibit toxic effects on a variety of cell types and organs. to determine the oxidative impact of cuo nps on hepatocellular carcinoma (hcc) cells, well-differentiated (hepg2) and poorly differentiated (sk-hep-1) cells were exposed to cuo nps. cell viability assay showed... | enhanced reactive oxygen species overexpression by cuo nanoparticles in poorly differentiated hepatocellular carcinoma cells |
the micro-imaging dust analysis system (midas) atomic force microscope (afm) onboard the rosetta orbiter was the first such instrument launched into space in 2004. designed only a few years after the technique was invented, midas is currently orbiting comet 67p churyumov-gerasimenko and producing the highest resolution... | midas: lessons learned from the first spaceborne atomic force microscope |
observations by the messenger spacecraft during its flyby and orbital observations of mercury in 2008-2015 indicated the presence of cold icy materials hiding in permanently-shadowed craters in mercury's north polar region. these icy condensed volatiles are thought to be composed of water ice and frozen organics that c... | ices on mercury: chemistry of volatiles in permanently cold areas of mercury's north polar region |
water ice exists on many objects in space. the most abundant icy species, among them water, are present in the icy satellites of the outer solar system giant planets. the nuclei of comets, which are mainly composed of water ice, give another example of its abundance. in the interstellar medium (ism), ice mantles, forme... | production of hydronium ion (h3o)+ and protonated water clusters (h2o)nh+ after energetic ion bombardment of water ice in astrophysical environments |
the european space agency's rosetta spacecraft, with the rosetta orbiter spectrometer for ion and neutral analysis (rosina) onboard, has been following and observing comet 67p/churyumov-gerasimenko since summer 2014. prior to this period, and due to a technical failure also during this period, optimization and calibrat... | sensitivity and fragmentation calibration of the time-of-flight mass spectrometer rtof on board esa's rosetta mission |
soon after the rosetta orbiter rendezvoused with comet 67p/churyumov-gerasimenko at a solar distance of ~3.5 au and began to fly in triangular-shaped trajectories around it, the ion and electron sensor detected negative particles at energies from about 100 ev/q to over 18 kev/q. the lower energy particles came from rou... | observation of charged nanograins at comet 67p/churyumov-gerasimenko |
as part of the european space agency's rosetta mission the lander philae touched down on comet 67p/churyumov-gerasimenko on november 12, 2014. the magnetic field has been measured onboard the orbiter and the lander. the orbiter's tri-axial fluxgate magnetometer rpc-mag is one of five sensors of the rosetta plasma conso... | attitude reconstruction of rosetta's lander philae using two-point magnetic field observations by romap and rpc-mag |
the onset of the paleocene-eocene thermal maximum (petm) and associated carbon isotope excursion (cie; approx. 56 mya) was geologically abrupt, but it is debated whether it took thousands of years or was effectively instantaneous. wright and schaller (2013) published a significant new record of the onset of the cie, an... | drilling disturbance and constraints on the onset of the paleocene-eocene boundary carbon isotope excursion in new jersey |
the in situ cometary dust particle instrument cosima (cometary secondary ion mass analyser) onboard esa's rosetta mission has collected about 31 000 dust particles in the inner coma of comet 67p/churyumov-gerasimenko since august 2014. the particles are identified by optical microscope imaging and analysed by time-of-f... | mechanical and electrostatic experiments with dust particles collected in the inner coma of comet 67p by cosima onboard rosetta |
anthropogenic point sources, such as coal-fired power plants, produce a major share of global co2 emissions. international climate agreements demand their independent monitoring. due to the large number of point sources and their global spatial distribution, the implementation of a satellite-based observation system is... | determination of the emission rates of co2 point sources with airborne lidar |
comets are constantly interacting with the solar wind. when the comet activity is high enough, this leads to the creation of a magnetic field free region around the nucleus known as the diamagnetic cavity. it has been suggested that the ion-neutral drag force is balancing the magnetic pressure at the cavity boundary, b... | ion bulk speeds and temperatures in the diamagnetic cavity of comet 67p from rpc-ica measurements |
in order to improve our understanding of landing on small bodies and of asteroid evolution, we use our novel drop tower facility to perform low-velocity (2-40 cm s-1), shallow impact experiments of a 10 cm diameter aluminum sphere into quartz sand in low effective gravities (∼0.2-1 m s-2). using in situ accelerometers,... | an experimental study of low-velocity impacts into granular material in reduced gravity |
the australasian tektite strewn field is exceptional, not only as the largest and most recent, but also as the only strewn field without an identified source impact crater. therefore, scenarios without the formation of an impact crater, such as a low altitude cometary airburst, have proven hard to discard. here, new ge... | on the nature of the ni-rich component in splash-form australasian tektites |
we have designed and built a laboratory facility to investigate the spectro-photometric and morphologic properties of different types of ice-bearing planetary surface analogs and follow their evolution upon exposure to a low pressure and low temperature environment. the results obtained with this experiment are used to... | the sciteas experiment: optical characterizations of sublimating icy planetary analogues |
airless bodies in the solar system are continually bombarded by meteoroids, sustaining impact ejecta clouds. while large bodies like the moon retain a significant fraction of ejecta, small asteroids shed this material into the interplanetary dust complex. measurements of the lunar impact ejecta cloud found it was susta... | impact ejecta environment of an eccentric asteroid: 3200 phaethon |
cosmic dust particles are mostly responsible for polarization of the light that we observe from astrophysical objects. they also lead to color-extinction, thermal re-emission and other scattering related phenomena. micrometric dust particles are often made of smaller constituent (nanometric grains). they are characteri... | the effect of porosity of dust particles on polarization and color with special reference to comets |
we outline the key questions about comets that must be answered in order to understand cometary formation in the context of the protoplanetary disc and the role of comets in the formation and evolution of the solar system. we then discuss the new understanding of comets from rosetta and from other recent advances, incl... | comets: looking ahead |
disintegrating planets allow for the unique opportunity to study the composition of the interiors of small, hot, rocky exoplanets because the interior is evaporating and that material is condensing into dust, which is being blown away and then transiting the star. their transit signal is dominated by dusty effluents fo... | inferring the composition of disintegrating planet interiors from dust tails with future james webb space telescope observations |
in the solar system, extra-terrestrial organic molecules have been found on cometary primitive objects, on titan and enceladus icy moons and on mars. identification could be achieved for simple organic species by remote sensing based on spectroscopic methods. however in situ mass spectrometry is a key technology to det... | identification of organic molecules with a laboratory prototype based on the laser ablation-cosmorbitrap |
using in situ measurements from different instruments on board the rosetta spacecraft, we investigate the properties of the newly discovered low-frequency oscillations, known as singing comet waves, that sometimes dominate the close plasma environment of comet 67p/churyumov-gerasimenko. these waves are thought to be ge... | properties of the singing comet waves in the 67p/churyumov-gerasimenko plasma environment as observed by the rosetta mission |
we use laboratory experiments to derive information on the chemistry occurring during the evolution of astrophysical ices from dense molecular clouds to interplanetary objects. through a new strategy that consists of coupling very high resolution mass spectrometry and infrared spectroscopy (ft-ir), we investigate the m... | cometary materials originating from interstellar ices: clues from laboratory experiments |
1. introduction; 2. dynamics; 3. solar heating and energy transport; 4. planetary atmospheres; 5. planetary surfaces; 6. planetary interiors; 7. magnetic fields and plasmas; 8. meteorites; 9. minor planets; 10. comets; 11. planetary rings; 12. extrasolar planets; 13. planet formation; 14. planets and life; appendixes; ... | planetary sciences |
planetary impact events eject large volumes of surface material. crater excavation processes are difficult to study, and in particular the details of individual ejecta fragments are not well understood. a related, enduring issue in planetary mapping is whether a given crater resulted from a primary impact (asteroid or ... | lunar secondary craters and estimated ejecta block sizes reveal a scale-dependent fragmentation trend |
solar system objects with perihelia beyond the orbit of jupiter (q > 5 au) are too cold for water ice to generate an appreciable coma via sublimation. despite this, numerous high-perihelion objects (hpos) including many comets and recently escaped kuiper belt objects (centaurs) are observed to be active out at least... | hubble space telescope search for activity in high-perihelion objects |
during its 1989 flyby, the voyager 2 spacecraft imaged six small moons of neptune, all with orbits well interior to that of the large, retrograde moon triton1. along with a set of nearby rings, these moons are probably younger than neptune itself; they formed shortly after the capture of triton and most of them have pr... | the seventh inner moon of neptune |
this paper provides a brief summary and overview of the astrochemistry associated with the formation of stars and planets. it is aimed at new researchers in the field to enable them to obtain a quick overview of the landscape and key literature in this rapidly evolving area. the journey of molecules from clouds to prot... | astrochemistry associated with planet formation |
this chapter focuses mainly on recent results obtained from observations on the mars express (mex) and venus express (vex) spacecraft. remote observations of cometary tails, which have also an induced origin, provide a lot of examples of sudden cometary tail disconnection that appear as a detachment of a very large pla... | magnetotails of mars and venus |
we present observations using the baade magellan and canada-france-hawaii telescopes showing that main-belt comet 324p/la sagra, formerly known as p/2010 r2, has become active again for the first time since originally observed to be active in 2010-2011. the object appears point-source-like in 2015 march and april as it... | the reactivation of main-belt comet 324p/la sagra (p/2010 r2) |
it has long been hypothesised that the jupiter-family comets (jfcs) come from the scattered disc, an unstable planetesimal population beyond neptune. this viewpoint has been widely accepted, but a few issues remain, the most prominent of which are the total number of visible jfcs with a perihelion distance q < 2.5 a... | an updated estimate of the number of jupiter-family comets using a simple fading law |
high-resolution infrared spectra of jupiter-family comet 45p/honda-mrkos-pajdušáková were obtained with nirspec at the w. m. keck observatory on two post-perihelion dates (ut 2017 february 13 and 19), when the comet was at heliocentric distances of 1.01 and 1.10 au, respectively. on ut february 13, h2o was measured sim... | post-perihelion volatile production and release from jupiter-family comet 45p/honda-mrkos-pajdušáková |
the collisional evolution of solid material in protoplanetary disks is a crucial step in the formation of planetesimals, comets, and planets. although dense protoplanetary environments favor fast dust coagulation, there are several factors that limit the straightforward pathway from interstellar micron-size grains to p... | inhibited coagulation of micron-size dust due to the electrostatic barrier |
the dynamics near the lagrange equilibria $l_1$ and $l_2$ of the circular restricted three-body problem has gained attention in the last decades due to its relevance in some topics such as the temporary captures of comets and asteroids and the design of trajectories for space missions. in this paper we investigate the ... | a study of temporary captures and collisions in the circular restricted three-body problem with normalizations of the levi-civita hamiltonian |
we examine the dynamics of small bodies in orbits similar to that of comet 29p/schwassmann-wachmann 1, i.e. near-circular orbits between jupiter and saturn. as of late 2019, there are 14 other known bodies in this region that lie in similar orbits. previous research has shown that this region of the solar system, which... | dynamics of small bodies in orbits between jupiter and saturn |
context. the esa rosetta probe has not seen direct evidence of a fully formed bow shock at comet 67p/churyumov-gerasimenko (67p). ion spectrometer measurements of cometary pickup ions measured in the vicinity of the nucleus of 67p are available and may contain signatures of the large-scale plasma environment.aims: the ... | hybrid modeling of cometary plasma environments. ii. remote-sensing of a cometary bow shock |
the present understanding of cometary atmospheres is based on whipple's "dirty iceball" idea in which the nucleus consists of a mixture of frozen volatiles and non-volatile dust. the atmospheres of comets, commonly referred to as comas, are different in a number of important ways from planetary atmospheres. this chapte... | physics of cometary magnetospheres |
despite the long escort by the esa rosetta mission, direct observations of a fully developed bow shock around 67p/churyumov-gerasimenko have not been reported. expanding on our previous work on indirect observations of a shock, we model the large-scale features in cometary pickup ions, and compare the results with the ... | remote sensing of cometary bow shocks: modelled asymmetric outgassing and pickup ion observations |
there was a color gradient of the coma along the radius r, approximately described by b-v=(0.3+/-0.2)+(0.2+/-0.2)*log10(r) for 4.1 =< r =< 9.6 arcsec. this indicates that the coma had a uniform color that was bluer than that of the sun regardless of the aperture radius r, or that the coma became redder with incre... | erratum of atel #16315: observations of comet 12p/pons-brooks after the july 19, 2023 outburst |
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