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context. since the orbital insertion of the rosetta spacecraft, comet 67p/churyumov-gerasimenko (67p) has been mapped by osiris camera and virtis spectro-imager, producing a huge quantity of images and spectra of the comet's nucleus.aims: the aim of this work is to search for the presence of h2o on the nucleus which, i... | detection of exposed h2o ice on the nucleus of comet 67p/churyumov-gerasimenko. as observed by rosetta osiris and virtis instruments |
hh 212 is one of the well-studied protostellar systems, showing the first vertically resolved disk with a warm atmosphere around the central protostar. here we report a detection of nine organic molecules (including newly detected ketene, formic acid, deuterated acetonitrile, methyl formate, and ethanol) in the disk at... | first abundance measurement of organic molecules in the atmosphere of hh 212 protostellar disk |
xenon (xe) is an exceptional tracer for investigating the origin and fate of volatile elements on earth. the initial isotopic composition of atmospheric xe remains unknown, as do the mechanisms involved in its depletion and isotopic fractionation compared with other reservoirs in the solar system. here we present high ... | the origin and degassing history of the earth's atmosphere revealed by archean xenon |
carbon dioxide (co2) is one of the most abundant species in cometary nuclei, but because of its high volatility, co2 ice is generally only found beneath the surface. we report the infrared spectroscopic identification of a co2 ice-rich surface area located in the anhur region of comet 67p/churyumov-gerasimenko. spectra... | seasonal exposure of carbon dioxide ice on the nucleus of comet 67p/churyumov-gerasimenko |
the data from all rosetta plasma consortium instruments and from the rosina cops instrument are used to study the interaction of the solar wind with the outgassing cometary nucleus of 67p/churyumov-gerasimenko. during 6 and 7 june 2015, the interaction was first dominated by an increase in the solar wind dynamic pressu... | mass-loading, pile-up, and mirror-mode waves at comet 67p/churyumov-gerasimenko |
europa likely contains an iron-rich metal core. for it to have formed, temperatures within europa reached ≳1250 k. going up to that temperature, accreted chondritic minerals — for example, carbonates and phyllosilicates — would partially devolatilize. here, we compute the amounts and compositions of exsolved volatiles.... | a metamorphic origin for europa's ocean |
we present a co(2-1) and 1240 μm continuum survey of 23 debris disks with spectral types b9-g1, observed at an angular resolution of 0.″5-1″ with the atacama large millimeter/submillimeter array (alma). the sample was selected for large infrared excess and age ∼10 myr, to characterize the prevalence of molecular gas em... | debris disks in the scorpius-centaurus ob association resolved by alma |
aims: we investigate the nucleus photometric properties of the comet 67p/churyumov-gerasimenko as observed by the visible and infrared thermal imaging spectrometer (virtis) onboard the rosetta spacecraft. both full-disk and disk-resolved images of the comet have been analyzed, deriving light and phase curves as well as... | photometric properties of comet 67p/churyumov-gerasimenko from virtis-m onboard rosetta |
bathed in intense ionizing radiation, close-in gaseous planets undergo hydrodynamic atmospheric escape, which ejects the upper extent of their atmospheres into the interplanetary medium. ultraviolet detections of escaping gas around transiting planets corroborate such a framework. exposed to the stellar environment, th... | morphology of hydrodynamic winds: a study of planetary winds in stellar environments |
we report the bulk c abundances, and c and o isotopic compositions of carbonates in 64 cm chondrites, 14 cr chondrites, 2 ci chondrites, lew 85332 (c2), kaba (cv3), and semarkona (ll3.0). for the unheated cms, the total ranges of carbonate isotopic compositions are δ13c ≈ 25-75‰ and δ18o ≈ 15-35‰, and bulk carbonate c ... | carbonate abundances and isotopic compositions in chondrites |
head-on collision among dust acoustic (da) multi-solitons in a dusty plasma with ions featuring non-maxwellian hybrid distribution under the effect of the polarization force is investigated. the presence of the non-maxwellian ions leads to eloquent modifications in the polarization force. specifically, an increase in t... | effect of polarization force on head-on collision between multi-solitons in dusty plasma |
low-mass protostars are the extrasolar analogues of the natal solar system. sophisticated physicochemical models are used to simulate the formation of two protoplanetary discs from the initial prestellar phase, one dominated by viscous spreading and the other by pure infall. the results show that the volatile prestella... | cometary ices in forming protoplanetary disc midplanes |
the activity of most comets near the sun is dominated by the sublimation of frozen water, the most abundant ice in comets. some comets, however, are active well beyond the water-ice sublimation limit of ∼3 au. three bodies dominate the observational record and modeling efforts for distantly active comets: the long-peri... | co in distantly active comets |
ammonium hydrosulphide has long since been postulated to exist at least in certain layers of the giant planets. its radiation products may be the reason for the red colour seen on jupiter. several ammonium salts, the products of nh3, and an acid have previously been detected at comet 67p/churyumov-gerasimenko. the acid... | abundant ammonium hydrosulphide embedded in cometary dust grains |
co and co2 are the two dominant carbon-bearing molecules in comae and have major roles in driving activity. their relative abundances also provide strong observational constraints to models of solar system formation and evolution but have never been studied together in a large sample of comets. we carefully compiled an... | a survey of co, co2, and h2o in comets and centaurs |
we present visible and near-infrared (nir) photometric and spectroscopic observations of interstellar object (iso) 2i/borisov taken from 2019 september 10 to 2019 december 20 using the growth, the apache point observatory astrophysical research consortium 3.5 m, and the nasa infrared telescope facility 3.0 m combined w... | characterization of the nucleus, morphology, and activity of interstellar comet 2i/borisov by optical and near-infrared growth, apache point, irtf, ztf, and keck observations |
the european space agency's rosetta mission1 has acquired unprecedented measurements of the surface of the nucleus of comet 67p/churyumov-gerasimenko (hereafter, 67p), the composition of which, as determined by in situ and remote-sensing instruments, including the virtis instrument2, seems to be an assemblage of ices, ... | infrared detection of aliphatic organics on a cometary nucleus |
infrared observations of the coma of 67p/churyumov-gerasimenko were carried out from 2015 july to september, i.e. around perihelion (2015 august 13), with the high-resolution channel of the visible and infrared thermal imaging spectrometer instrument onboard rosetta. we present the analysis of fluorescence emission lin... | evolution of co2, ch4, and ocs abundances relative to h2o in the coma of comet 67p around perihelion from rosetta/virtis-h observations |
we present a multi-wavelength study of comet c/2016 r2 (panstarrs). this comet was observed on 23 and 24 january 2018 with the iram 30 m telescope, and in january to march 2018 with the nançay radio telescope. visible spectroscopy was performed in december 2017 and february 2018 with small amateur telescopes. we report... | the extraordinary composition of the blue comet c/2016 r2 (panstarrs) |
the classic accepted view of the heliosphere is a quiescent, comet-like shape aligned in the direction of the sun’s travel through the interstellar medium (ism) extending for thousands of astronomical units (aus). here, we show, based on magnetohydrodynamic (mhd) simulations, that the tension (hoop) force of the twiste... | magnetized jets driven by the sun: the structure of the heliosphere revisited |
isotopic ratios provide a powerful tool for understanding the origins of materials, including the volatile and refractory matter within solar system bodies. recent high sensitivity observations of molecular isotopologues, in particular with alma, have brought us new information on isotopic ratios of hydrogen, carbon, n... | the isotopic links from planet forming regions to the solar system |
aims: the osiris camera on board the rosetta spacecraft has been acquiring images of the comet 67p/churyumov-gerasimenko (67p)'s nucleus since august 2014. starting in may 2015, the southern hemisphere gradually became illuminated and was imaged for the first time. here we present the regional morphology of the souther... | regional surface morphology of comet 67p/churyumov-gerasimenko from rosetta/osiris images: the southern hemisphere |
the rosetta lander philae is part of the esa rosetta mission which reached comet 67p/churyumov-gerasimenko after a 10 year cruise in august 2014. since then, rosetta has been studying both its nucleus and coma with instruments aboard the orbiter. on november 12th, 2014 the lander, philae, was successfully delivered to ... | rosetta lander - landing and operations on comet 67p/churyumov-gerasimenko |
67p/churyumov-gerasimenko (67p) is a jupiter-family comet and the object of investigation of the european space agency mission rosetta. this report presents the first full 3d simulation results of 67p's neutral gas coma. in this study we include results from a direct simulation monte carlo method, a hydrodynamic code, ... | comparison of 3d kinetic and hydrodynamic models to rosina-cops measurements of the neutral coma of 67p/churyumov-gerasimenko |
this paper is the result of the international cometary workshop, held in toulouse, france in april 2014, where the participants came together to assess our knowledge of comets prior to the esa rosetta mission. in this paper, we look at the composition of the gas and dust from the comae of comets. with the gas, we cover... | the composition of comets |
we study the development of activity in the incoming long-period comet c/2017 k2 over the heliocentric distance range 9 ≲ rh ≲ 16 au. the comet continues to be characterized by a coma of submillimeter-sized and larger particles ejected at low velocity. in a fixed co-moving volume around the nucleus we find that the sca... | cometary activity begins at kuiper belt distances: evidence from c/2017 k2 |
context. the study of large and representative samples of low-metallicity star-forming galaxies at different cosmic epochs is of great interest to the detailed understanding of the assembly history and evolution of low-mass galaxies.aims: we present a thorough characterization of a large sample of 183 extreme emission-... | extreme emission-line galaxies out to z ~ 1 in zcosmos. i. sample and characterization of global properties |
comet c/2014 un271 (bernardinelli-bernstein), incoming from the oort cloud, is remarkable in having the brightest (and presumably largest) nucleus of any well-measured comet and having been discovered at the heliocentric distance rh ≈ 29 au, farther than any oort cloud comet. in this work, we describe the discovery pro... | c/2014 un271 (bernardinelli-bernstein): the nearly spherical cow of comets |
based on new high-resolution multi-beam bathymetry and multichannel seismic reflection data, two new groups of numerous pockmarks and mud volcanoes were discovered in the northern zhongjiannan basin at water depths between 600 and 1400 m. individual pockmarks are circular, elliptical, crescent-shaped or elongated, with... | morphologies, classification and genesis of pockmarks, mud volcanoes and associated fluid escape features in the northern zhongjiannan basin, south china sea |
context. during the period between 15 september 2014 and 4 february 2015, the rosetta spacecraft accomplished the circular orbit phase around the nucleus of comet 67p/churyumov-gerasimenko (67p). the grain impact analyzer and dust accumulator (giada) onboard rosetta monitored the 67p coma dust environment for the entir... | giada: shining a light on the monitoring of the comet dust production from the nucleus of 67p/churyumov-gerasimenko |
life on earth employs chiral amino acids in stereochemical l-form, but the cause of molecular symmetry breaking remains unknown. chiroptical properties of amino acids - expressed in circular dichroism (cd) - have been previously investigated in solid and solution phase. however, both environments distort the intrinsic ... | amino acid gas phase circular dichroism and implications for the origin of biomolecular asymmetry |
a theoretical investigation has been presented to study the effect of polarization force on nonlinear dust acoustic (da) cnoidal waves in dusty plasma composed of negatively charged dust fluid, maxwellian electrons and superthermally distributed ions. the effect of polarization force is significantly modified due to th... | effect of polarization force on dust-acoustic cnoidal waves in dusty plasma |
we propose to identify the main sources of ionization of the plasma in the coma of comet 67p/churyumov-gerasimenko at different locations in the coma and to quantify their relative importance, for the first time, for close cometocentric distances (<20 km) and large heliocentric distances (>3 au). the ionospheric ... | ionospheric plasma of comet 67p probed by rosetta at 3 au from the sun |
the long duration of the rosetta mission allows us to study the evolution of the diamagnetic cavity at comet 67p/churyumov-gerasimenko in detail. from 2015 april to 2016 february 665 intervals could be identified where rosetta was located in a zero-magnetic-field region. we study the temporal and spatial distribution o... | structure and evolution of the diamagnetic cavity at comet 67p/churyumov-gerasimenko |
comet c/2019 q4 (borisov) -later renamed 2i/borisov- was discovered on august 30, 2019 by g. borisov observing from crimea. the value of its orbital eccentricity was initially found to be over 3.6 that made this object only the second interstellar minor body ever found, after 1i/2017 u1 ('oumuamua). here, we present ea... | interstellar visitors: a physical characterization of comet c/2019 q4 (borisov) with osiris at the 10.4\u2009m gtc |
the recent analysis of the composition of the frozen surface of comet 67p/churyumov-gerasimenko has revealed a significant number of complex organic molecules. methyl isocyanate (ch3nco) is one of the more abundant species detected on the comet surface. in this work we report extensive characterization of its rotationa... | a rigorous detection of interstellar ch3nco: an important missing species in astrochemical networks |
heat transport and ice sublimation in comets are interrelated processes reflecting properties acquired at the time of formation and during subsequent evolution. the microwave instrument on the rosetta orbiter (miro) acquired maps of the subsurface temperature of comet 67p/churyumov-gerasimenko, at 1.6 mm and 0.5 mm wav... | subsurface properties and early activity of comet 67p/churyumov-gerasimenko |
the cometary secondary ion mass analyser instrument on board esa's rosetta mission has collected dust particles in the coma of comet 67p/churyumov-gerasimenko. during the early-orbit phase of the rosetta mission, particles and particle agglomerates have been imaged and analyzed in the inner coma at distances between 10... | comet 67p/churyumov-gerasimenko: close-up on dust particle fragments |
as the spin axis of comet 67p/churyumov-gerasimenko (67p) is not normal to the orbital plane, 67p has strong seasonal changes in the illumination conditions on the nucleus' surface, with a short and intense summer in the southern hemisphere. we have been monitoring these seasonal variations in the gas coma with the ros... | change of outgassing pattern of 67p/churyumov-gerasimenko during the march 2016 equinox as seen by rosina |
we present high spectral resolution optical spectra obtained with the arces instrument at apache point observatory showing detection of the [o i] 6300 å line in interstellar comet 2i/borisov. we employ the observed flux in this line to derive an h2o production rate of (6.3 ± 1.5) × 1026 mol s-1. comparing to previously... | detection of a water tracer in interstellar comet 2i/borisov |
aims: the two stable isotopes of nitrogen, 14n and 15n, exhibit a range of abundance ratios both inside and outside the solar system. the elemental ratio in the solar neighborhood is 440. recent alma observations showed hcn/hc15n ratios from 83 to 156 in six t tauri and herbig disks and a cn/c15n ratio of 323 ± 30 in o... | nitrogen isotope fractionation in protoplanetary disks |
context. the origin of the particular shape of comet 67p/churyumov-gerasimenko (67p) is a topic of active research. how and when it acquired its peculiar characteristics has distinct implications on the origin of the solar system and its dynamics.aims: we investigate how shapes such as that of comet 67p can result from... | formation of bi-lobed shapes by sub-catastrophic collisions. a late origin of comet 67p's structure |
the origin of terrestrial volatiles remains one of the most puzzling questions in planetary sciences. the timing and composition of chondritic and cometary deliveries to earth has remained enigmatic due to the paucity of reliable measurements of cometary material. this work uses recently measured volatile elemental rat... | the origin and fate of volatile elements on earth revisited in light of noble gas data obtained from comet 67p/churyumov-gerasimenko |
context. sulfur is a biogenic element used as a tracer of the evolution of interstellar clouds to stellar systems. however, most of the expected sulfur in molecular clouds remains undetected. sulfur disappears from the gas phase in two steps. the first depletion occurs during the translucent phase, reducing the gas-pha... | photoprocessing of h2s on dust grains. building s chains in translucent clouds and comets |
models of the solar system's 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 instabilities1. accordingly, minor bodies should also be ejected from other planetary systems and should be abundant in the interst... | tumbling motion of 1i/`oumuamua and its implications for the body's distant past |
ablation of interplanetary dust supplies oxygen to the upper atmospheres of jupiter, saturn, uranus, and neptune. using recent dynamical model predictions for the dust influx rates to the giant planets (poppe et al., 2016), we calculate the ablation profiles and investigate the subsequent coupled oxygen-hydrocarbon neu... | dust ablation on the giant planets: consequences for stratospheric photochemistry |
context. the gas-driven dust activity of comets is still an unsolved question in cometary physics. homogeneous dust layers composed of micrometer-sized grains possess tensile strengths of ~1 kpa, which is far higher than typical gas pressures caused by the sublimation of the ices beneath the covering dust layer. this i... | what drives the dust activity of comet 67p/churyumov-gerasimenko? |
when a weakly outgassing comet is sufficiently close to the sun, the formation of an ionized coma results in solar wind mass loading and magnetic field draping around its nucleus. using a 3d fully kinetic approach, we distill the components of a generalized ohm's law and the effective electron equation of state directl... | building a weakly outgassing comet from a generalized ohm's law |
an introduction to celestial mechanics for advanced undergraduates, graduate students, and researchers new to the fieldcelestial mechanics—the study of the movement of planets, satellites, and smaller bodies such as comets—is one of the oldest subjects in the physical sciences. since the mid-twentieth century, the fiel... | dynamics of planetary systems |
formamide (nh$_2$cho) has been identified as a potential precursor of a wide variety of organic compounds essential to life, and many biochemical studies propose it likely played a crucial role in the context of the origin of life on our planet. the detection of formamide in comets, which are believed to have --at leas... | interstellar formamide (nh2cho), a key prebiotic precursor |
we study the solution $h_\varepsilon$ of the kardar-parisi-zhang (kpz) equation for $d \geq 3$: $$ \frac{\partial}{\partial t} h_{\varepsilon} = \frac12 \delta h_{\varepsilon} + \bigg[\frac12 |\nabla h_\varepsilon |^2 - c_\varepsilon\bigg]+ \beta \varepsilon^{\frac{d-2}2} \xi_{\varepsilon} $$ with $h_\varepsilon(0,x)=0... | space-time fluctuation of the kardar-parisi-zhang equation in $d\\geq 3$ and the gaussian free field |
from august to november 2014 the rosetta orbiter has performed an extensive observation campaign aimed at the characterization of 67p/cg nucleus properties and to the selection of the philae landing site. the campaign led to the production of a global map of the illuminated portion of 67p/cg nucleus. during this prelan... | the global surface composition of 67p/cg nucleus by rosetta/virtis. (i) prelanding mission phase |
deuterated methanol is one of the most robust windows astrochemists have on the individual chemical reactions forming deuterium-bearing molecules and the physicochemical history of the regions where they reside. the first-time detection of mono- and di-deuterated methanol in a cometary coma is presented for comet 67p/c... | prestellar grain-surface origins of deuterated methanol in comet 67p/churyumov-gerasimenko |
we present 2-5 μm spectroscopic observations of the dust coma of 67p/churyumov-gerasimenko obtained with the virtis-h instrument onboard rosetta during two outbursts that occurred on 2015, 13 september 13.6 h ut and 14 september 18.8 h ut at 1.3 au from the sun. scattering and thermal properties measured before the out... | comet 67p outbursts and quiescent coma at 1.3 au from the sun: dust properties from rosetta/virtis-h observations |
the european space agency rosetta/philae mission to comet 67p/churyumov-gerasimenko in 2014-2016 is the most complete and diverse investigation of a comet carried out thus far. yet, many physical and chemical properties of the comet remain uncertain or unknown, and cometary activity is still not a well-understood pheno... | modelling the water and carbon dioxide production rates of comet 67p/churyumov-gerasimenko |
this study aimed at comparative examining of the interactions between conventionally used clay and carbon nanomaterials and human lung adenocarcinoma cells (a549 cells). the following platy and tubular nanomaterials were tested: carbon nanoparticles, i.e. multi-walled carbon nanotubes (mwcnts) and graphene oxide nanosh... | comparative cytotoxicity of kaolinite, halloysite, multiwalled carbon nanotubes and graphene oxide |
this present investigation has been instigated to examine the impact of polarization force on modulational instability of dust acoustic (da) waves and transition of rogue wave triplets to super rogue waves in dusty plasma composed of negative dust as fluid, boltzmannian electrons, and superthermal ions. the presence of... | the evolution of rogue wave triplets and super rogue waves in superthermal polarized space dusty plasma |
context. outgassing from cometary nuclei involves complex surface and subsurface processes that need to be understood to investigate the composition of cometary ices from coma observations.aims: we investigate the production of water, carbon dioxide, and carbon monoxide from the nucleus of comet 67p/churyumov-gerasimen... | first observations of h2o and co2 vapor in comet 67p/churyumov-gerasimenko made by virtis onboard rosetta |
isotopic ratios are keys to understanding the origin and early evolution of the solar system in the context of galactic nucleosynthesis. the large range of measured 14n/15n isotopic ratios in the solar system reflects distinct reservoirs of nitrogen whose origins remain to be determined. we have directly measured a c14... | direct evidence of multiple reservoirs of volatile nitrogen in a protosolar nebula analogue |
we present an x-ray and radio study of the famous `el gordo', a massive and distant (z = 0.87) galaxy cluster. in the deep (340 ks) chandra observation, the cluster appears with an elongated and cometary morphology, a sign of its current merging state. the gmrt radio observations at 610 mhz confirm the presence of a ra... | a m ≳ 3 shock in `el gordo' cluster and the origin of the radio relic |
the rosetta spacecraft spent ~2 years orbiting comet 67p/churyumov-gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. from december 2014 to june 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and tra... | surface changes on comet 67p/churyumov-gerasimenko suggest a more active past |
comets contain abundant amounts of organic and inorganic species. many of the volatile molecules in comets have also been observed in the interstellar medium and some of them even with similar relative abundances, indicating formation under similar conditions or even sharing a common chemical pathway. there is a growin... | volatile species in comet 67p/churyumov-gerasimenko: investigating the link from the ism to the terrestrial planets |
context. the rosetta mission and its exquisite measurements have revived the debate on whether comets are pristine planetesimals or collisionally evolved objects.aims: we investigate the collisional evolution experienced by the precursors of current comet nuclei during the early stages of the solar system in the contex... | comets as collisional fragments of a primordial planetesimal disk |
molecular oxygen has been confirmed as the fourth most abundant molecule in cometary material (o2/h2o ∼ 4 per cent) and is thought to have a primordial nature, i.e. coming from the interstellar cloud from which our solar system was formed. however, interstellar o2 gas is notoriously difficult to detect and has only bee... | a primordial origin for molecular oxygen in comets: a chemical kinetics study of the formation and survival of o2 ice from clouds to discs |
context. the scattering properties of the dust originating from debris discs are still poorly known. the analysis of scattered light is however a powerful remote-sensing tool to understand the physical properties of dust particles orbiting other stars. scattered light is indeed widely used to characterise the propertie... | optical polarised phase function of the hr 4796a dust ring |
although there is evidence for periodic geological perturbations driven by regular or semi-regular extra-terrestrial bombardment, the production of earth's continental crust is generally regarded as a function of planetary differentiation driven by internal processes. we report time series analysis of the hf isotopic c... | did transit through the galactic spiral arms seed crust production on the early earth? |
context. the rosetta spacecraft is escorting comet 67p/churyumov-gerasimenko from a heliocentric distance of >3.6 au, where the comet activity was low, until perihelion at 1.24 au. initially, the solar wind permeates the thin comet atmosphere formed from sublimation.aims: using the rosetta plasma consortium ion comp... | evolution of the ion environment of comet 67p/churyumov-gerasimenko. observations between 3.6 and 2.0 au |
bilobate comets—small icy bodies with two distinct lobes—are a common configuration among comets, but the factors shaping these bodies are largely unknown. cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the sun, but the importance of a comet's internal structu... | bilobate comet morphology and internal structure controlled by shear deformation |
the fractal dust particles observed by rosetta cannot form in the physical conditions observed today in comet 67p/churyumov-gerasimenko (67p hereinafter), being instead consistent with models of the pristine dust aggregates coagulated in the solar nebula. since bouncing collisions in the protoplanetary disc restructure... | fractal dust constrains the collisional history of comets |
mid-infrared spectra of amorphous and crystalline acetone are presented along with measurements of the refractive index and density for both forms of the compound. infrared band strengths are reported for the first time for amorphous and crystalline acetone, along with ir optical constants. vapor pressures and a sublim... | ir spectra and properties of solid acetone, an interstellar and cometary molecule |
the radiation data collected by the standard radiation environment monitor (srem) aboard esa missions integral (international gamma-ray astrophysics laboratory), rosetta, herschel, planck and proba-1, and by the high-energy neutron detector (hend) instrument aboard mars odyssey, are analysed with an emphasis on charact... | multi-point galactic cosmic ray measurements between 1 and 4.5 au over a full solar cycle |
soon after the arrival of the rosetta spacecraft at comet 67/p churyumov-gerasimenko the onboard instrument cosima ("cometary secondary ion mass analyzer") collected a large number of cometary dust particles on targets from gold black of thickness between 10 and 30 μm. inspection by its camera subsystem revealed that m... | a first assessment of the strength of cometary particles collected in-situ by the cosima instrument onboard rosetta |
the surfaces of many objects in the solar system comprise substantial quantities of water ice sometimes mixed with minerals and/or organic molecules. the sublimation of the ice changes the structural and optical properties of these objects. we present laboratory data on the evolution of the structure and the visible an... | sublimation of water ice mixed with silicates and tholins: evolution of surface texture and reflectance spectra, with implications for comets |
the geophysical evolution of many icy moons and dwarf planets seems to have provided opportunities for interaction between liquid water and rock (silicate and organic solids). here, we explore two ways by which water-rock interaction can feed back on geophysical evolution: the production or consumption of antifreeze co... | aqueous geochemistry in icy world interiors: equilibrium fluid, rock, and gas compositions, and fate of antifreezes and radionuclides |
the european rosetta mission has been following comet 67p/churyumov-gerasimenko for 2 years, studying the nucleus and coma in great detail. for most of these 2 years the rosetta orbiter sensor for ion and neutral analysis (rosina) has analysed the volatile part of the coma. with its high mass resolution and sensitivity... | d2o and hds in the coma of 67p/churyumov-gerasimenko |
the gj 436 planetary system is an extraordinary system. the neptune-sized planet that orbits the m3 dwarf revealed in the ly α line an extended neutral hydrogen atmosphere. this material fills a comet-like tail that obscures the stellar disc for more than 10 h after the planetary transit. here, we carry out a series of... | gj 436b and the stellar wind interaction: simulations constraints using ly α and h α transits |
the structure of the kreutz system of sungrazing comets is shown to be much more complex than formerly believed. marsden's (1989) division into three subgroups (i, ii, iia) is now greatly expanded, as new evidence is being offered on nine populations of fragments -- i, ia, ii, iia, iii, pre-i, pe (side branch of i), ii... | new model for the kreutz sungrazer system: contact-binary parent and upgraded classification of discrete fragment populations |
given its abundant coal mining activities, the upper silesian coal basin (uscb) in southern poland is one of the largest sources of anthropogenic methane (ch4) emissions in europe. here, we report on ch4 emission estimates for coal mine ventilation facilities in the uscb. our estimates are driven by pairwise upwind-dow... | observational constraints on methane emissions from polish coal mines using a ground-based remote sensing network |
aims: we search for signs of falling evaporating bodies (febs, also known as exocomets) in photometric time series obtained for β pictoris after fitting and removing its δ scuti-type pulsation frequencies.methods: using photometric data obtained by the tess satellite we determined the pulsational properties of the exop... | transiting exocomets detected in broadband light by tess in the β pictoris system |
we use measurements from the rosetta plasma consortium langmuir probe and mutual impedance probe to study the spatial distribution of low-energy plasma in the near-nucleus coma of comet 67p/churyumov-gerasimenko. the spatial distribution is highly structured with the highest density in the summer hemisphere and above t... | spatial distribution of low-energy plasma around comet 67p/cg from rosetta measurements |
the basic properties of nonlinear ion-acoustic (ia) waves (iaws), particularly finite amplitude ia rogue waves (iarws) in a plasma medium (containing pair ions, iso-thermal positrons, and non-thermal electrons) are theoretically investigated by deriving the nonlinear schrödinger equation (nlse). the criteria for the mo... | ion-acoustic rogue waves in multi-ion plasmas |
29p/schwassmann-wachmann is an unusual solar system object. originally classified as a short-period comet, it is now known as a centaur that recently transferred to its current orbit, and may become a jupiter family comet. it has exhibited a dust coma for over 90 yr, and regularly undergoes significant dust outbursts. ... | co gas and dust outbursts from centaur 29p/schwassmann-wachmann |
the oort cloud and the scattered disk are the two primary reservoirs for long-period and short-period comets, respectively. in this review, we assess the known observational constraints on these reservoirs' properties and their formation. in addition, we discuss how the early orbital evolution of the giant planets gene... | dynamical population of comet reservoirs |
kuiper belt objects, such as arrokoth, the probable progenitors of short-period comets, formed and evolved at large heliocentric distances, where the ambient temperatures appear to be sufficiently low for preserving volatile ices. by detailed numerical simulations, we follow the long-term evolution of small bodies, com... | sublimation of ices during the early evolution of kuiper belt objects |
observations of the nucleus of 67p/churyumov-gerasimenko in the millimeter-wave continuum have been obtained by the microwave instrument for the rosetta orbiter (miro). we present data obtained at wavelengths of 0.5 mm and 1.6 mm during september 2014 when the nucleus was at heliocentric distances between 3.45 and 3.27... | miro observations of subsurface temperatures of the nucleus of 67p/churyumov-gerasimenko |
context. strong electron cooling on the neutral gas in cometary comae has been predicted for a long time, but actual measurements of low electron temperature are scarce.aims: our aim is to demonstrate the existence of cold electrons in the inner coma of comet 67p/churyumov-gerasimenko and show filamentation of this pla... | cold and warm electrons at comet 67p/churyumov-gerasimenko |
aims: the alice far-ultraviolet spectrograph onboard rosetta is designed to observe emissions from various atomic and molecular species from within the coma of comet 67p/ churyumov-gerasimenko and to determine their spatial distribution and evolution with time and heliocentric distance.methods: following orbit insertio... | measurements of the near-nucleus coma of comet 67p/churyumov-gerasimenko with the alice far-ultraviolet spectrograph on rosetta |
lyman α transits have been detected from several nearby exoplanets and are one of our best insights into the atmospheric escape process. however, due to ism absorption, we typically only observe the transit signature in the blue-wing, making them challenging to interpret. this challenge has been recently highlighted by... | the fundamentals of lyman α exoplanet transits |
we have studied four complex organic molecules (coms), the oxygen-bearing methyl formate (ch3ocho) and dimethyl ether (ch3och3) as well as the nitrogen-bearing formamide (nh2cho) and ethyl cyanide (c2h5cn), towards a large sample of 39 high-mass star-forming regions representing different evolutionary stages, from earl... | evolutionary study of complex organic molecules in high-mass star-forming regions |
comet 2i/borisov, the first unambiguous interstellar comet ever found, was discovered in 2019 august at ∼3 au from the sun on its inbound leg. no pre-discovery detection beyond 3 au has yet been reported, mostly due to the comet's proximity to the sun as seen from the earth. here we present a search for pre-discovery d... | pre-discovery activity of new interstellar comet 2i/borisov beyond 5 au |
pulsar wind nebulae (pwn) are fascinating systems and archetypal sources for high-energy astrophysics in general. due to their vicinity, brightness, to the fact that they shine at multi-wavelengths, and especially to their long-living emission at gamma rays, modelling their properties is particularly important for the ... | the dawes review 11: from young to old: the evolutionary path of pulsar wind nebulae |
the solid, central part of a comet—its nucleus—is subject to destructive processes, which cause nuclei to split at a rate of about 0.01 per year per comet. these destructive events are due to a range of possible thermophysical effects; however, the geophysical expressions of these effects are unknown. separately, over ... | fission and reconfiguration of bilobate comets as revealed by 67p/churyumov-gerasimenko |
rosetta has followed comet 67p from low activity at more than 3.6 au heliocentric distance to high activity at perihelion (1.24 au) and then out again. we provide a general overview of the evolution of the dynamic ion environment using data from the rpc-ica ion spectrometer. we discuss where rosetta was located within ... | evolution of the ion environment of comet 67p during the rosetta mission as seen by rpc-ica |
there are plenty of monitoring methods to quantify gas emission rates based on gas concentration measurements around the strong sources. however, there is a lack of quantitative models to evaluate methane emission rates from coal mines with less prior information. in this study, we develop a genetic algorithm-interior ... | retrieving ch4-emission rates from coal mine ventilation shafts using uav-based aircore observations and the genetic algorithm-interior point penalty function (ga-ippf) model |
context. several sulfur-bearing molecules are observed in the interstellar medium and in comets, in strong contrast to protoplanetary disks where only cs, h2cs, and so have been detected so far.aims: we combine observations and chemical models to constrain the sulfur abundances and their sensitivity to physical and che... | chemistry in disks. xi. sulfur-bearing species as tracers of protoplanetary disk physics and chemistry: the dm tau case |
kuiper belt objects, or more generally trans-neptunian objects (tnos), are planetesimals found beyond the orbit of neptune. some tnos evolve onto neptune-crossing orbits and become centaurs. many centaurs, in turn, reach jupiter-crossing orbits and become jupiter-family comets (jfcs). tnos are the main source of the jf... | the transition from the kuiper belt to the jupiter-family (comets) |
thermal and mechanical material properties determine comet evolution and even solar system formation because comets are considered remnant volatile-rich planetesimals. using data from the multipurpose sensors for surface and sub-surface science (mupus) instrument package gathered at the philae landing site abydos on co... | thermal and mechanical properties of the near-surface layers of comet 67p/churyumov-gerasimenko |
we report new light curves and phase functions for nine jupiter-family comets (jfcs). they were observed in the period 2004-2015 with various ground telescopes as part of the survey of ensemble physical properties of cometary nuclei as well as during devoted observing campaigns. we add to this a review of the propertie... | rotation of cometary nuclei: new light curves and an update of the ensemble properties of jupiter-family comets |
the metastable helium (he*) lines near 10830 å are ideal probes of atmospheric erosion-a common phenomenon of close-in exoplanet evolution. a handful of exoplanet observations yielded well-resolved he* absorption features in transits, yet they were mostly analyzed with 1d isothermal models prescribing mass-loss rates. ... | metastable helium absorptions with 3d hydrodynamics and self-consistent photochemistry. i. wasp-69b, dimensionality, x-ray and uv flux level, spectral types, and flares |
the composition of cometary ices provides key information on the thermal and chemical properties of the outer parts of the protoplanetary disk where they formed 4.6 gy ago. this chapter reviews our knowledge of composition of cometary comae based on remote spectroscopy and in-situ investigations techniques. cometary co... | chemistry of comet atmospheres |
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