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consert, a bistatic radar onboard the rosetta spacecraft and its philae lander, was designed to probe the nucleus of comet 67p/churyumov-gerasimenko with radio waves at 90 mhz frequency. in 2016 september, the exact position of philae was retrieved, within the region previously identified by consert. this allowed us to... | the interior of comet 67p/c-g; revisiting consert results with the exact position of the philae lander |
on neptune, carbon monoxide and phosphine are disequilibrium species, and their abundance profiles can provide insights into interior processes and the external space environment. here we use herschel/spire (spectral and photometric imaging receiver) observations from 14.9-51.5 cm-1 to obtain abundances from multiple c... | neptune's carbon monoxide profile and phosphine upper limits from herschel/spire: implications for interior structure and formation |
context. the rosetta orbiter spectrometer for ion and neutral analysis (rosina) was designed to measure the composition of the gas in the coma of comet 67p/churyumov-gerasimenko, the target of the european space agency's rosetta mission. in addition to the volatiles, rosina measured refractories sputtered off the comet... | evidence for depletion of heavy silicon isotopes at comet 67p/churyumov-gerasimenko |
context. evaporating rocky exoplanets, such as kic 12557548b, eject large amounts of dust, which can trail the planet in a comet-like tail. when such objects occult their host star, the resulting transit signal contains information about the dust in the tail.aims: we aim to use the detailed shape of the kepler light cu... | dusty tails of evaporating exoplanets. ii. physical modelling of the kic 12557548b light curve |
water has two nuclear-spin isomers: ortho- and para-h2o. some observations of interstellar space and cometary comae have reported the existence of gaseous h2o molecules with anomalous ortho-to-para ratios (oprs) less than the statistical value of three. this has been often used to estimate the formation temperature of ... | the ortho-to-para ratio of water molecules desorbed from ice made from para-water monomers at 11 k |
aims: we develop a physical model to explain the potent outbursts that occurred in the fractured terrain of comet 67p near perihelion, and predict its temporal characteristics.methods: the feasibility of the proposed mechanism is studied using a numerical model accounting for the relevant microscopic/macroscopic proces... | a model of short-lived outbursts on the 67p from fractured terrains |
as a new class of comet, main belt comets (mbcs) have attracted more and more attention in recent years. to study activity and physical properties of three mbcs 176p/linear, 238p/read and 288p/(300163) 2006 vw139, we carried out broadband ccd photometry of three mbcs on ut 2016 november 18-19 with the 1-m optical teles... | research of activity of main belt comets 176p/linear, 238p/read and 288p/(300163) 2006 vw139 |
context. the solar radiation in the lyman-α spectral line of hydrogen plays a significant role in the illumination of chromospheric and coronal structures, such as prominences, spicules, chromospheric fibrils, cores of coronal mass ejections, and solar wind. moreover, it is important for the investigation of the helios... | quiet-sun hydrogen lyman-α line profile derived from soho/sumer solar-disk observations |
debris disks are extrasolar analogs to our own kuiper belt and they are detected around at least 17% of nearby sun-like stars. the morphology and dynamics of a disk encode information about its history, as well as that of any exoplanets within the system. we used the atacama large millimeter/submillimeter array (alma) ... | the reasons survey: resolved millimeter observations of a large debris disk around the nearby f star hd 170773 |
aims: we present the most extensive catalog of exposures of volatiles on the 67p/churyumov-gerasimenko nucleus generated from observations acquired with the optical, spectroscopic, and infrared remote imaging system (osiris) on board the rosetta mission. we investigate the volatile exposure distribution across the nucl... | volatile exposures on the 67p/churyumov-gerasimenko nucleus |
we report observations of nine main-belt comets (mbcs) or candidate mbcs, most of which were obtained when the targets were apparently inactive. we find effective nucleus radii (assuming albedos of pv= 0.05 ± 0.02) of rn= (0.24 ± 0.05) km for 238p/read, rn= (0.9 ± 0.2) km for 313p/gibbs, rn= (0.6 ± 0.1) km for 324p/la ... | observational characterization of main-belt comet and candidate main-belt comet nuclei |
we report the first survey of molecular emission from cometary volatiles using standalone atacama compact array (aca) observations from the atacama large millimeter/submillimeter array (alma) toward comet c/2015 er61 (panstarrs) carried out on ut 2017 april 11 and 15, shortly after its april 4 outburst. these measureme... | leveraging the alma atacama compact array for cometary science: an interferometric survey of comet c/2015 er61 (panstarrs) and evidence for a distributed source of carbon monosulfide |
we present x-ray and radio observations of the recently discovered bow-shock pulsar wind nebula (pwn) associated with psr j0002+6216, characterizing the pwn morphology, which was unresolved in previous studies. the multifrequency, multiepoch very large array (vla) radio observations reveal a cometary tail trailing the ... | resolving the bow shock and tail of the cannonball pulsar psr j0002+6216 |
the τ-herculids (iau shower number 61 tah) is a minor meteor shower associated with comet 73p/schwassmann-wachmann 3, a jupiter-family comet that disintegrated into several fragments in 1995. as a consequence of the nucleus breakup, possible increased meteor rates were predicted for 2022. on may 30-31, observation netw... | modeling the 2022 τ-herculid outburst |
numerous studies of cometary dust have shown that it has a fairly complex hierarchical structure. at the same time, space missions have provided evidence of solid particles. computer modeling of light scattering, for which agglomerate debris particles were used, showed that the characteristics of the scattered light st... | polarization properties of quasi-fractal porous particles |
surface processes and radical chemistry within interstellar ices are increasingly suspected to play an important role in the formation of complex organic molecules (coms) observed in several astrophysical regions and cometary environments. we present new laboratory experiments on the low-temperature solid state formati... | radical-induced chemistry from vuv photolysis of interstellar ice analogues containing formaldehyde |
high-resolution osiris/rosetta images of 67p/churyumov-gerasimenko acquired on the night run of 2016 april 9-10 show, at large scale, an opposition effect (oe) spot sweeping across imhotep as the phase angle ranges from 0° to 17°. in this work, we fitted the phase curve of the whole surface imaged as well as three part... | the opposition effect of 67p/churyumov-gerasimenko on post-perihelion rosetta images |
the geminid meteor shower was observed in 2015 using the western meteor physics group's canadian meteor orbit radar (cmor), marshall space flight center's (msfc) eight wide-field optical cameras, and telescopes of msfc's lunar impact monitoring program. these observations allowed geminid fluxes to be calculated in thre... | the mass index and mass of the geminid meteoroid stream as determined with radar, optical and lunar impact data |
context. ic 63 and ic 59 are a pair of cometary-shaped nebulae in the vicinity of the star γcas (also known as tsih, "the whip"). both nebulae have very different optical appearances, despite the fact that both objects lie at similar projected distances from the star: ic 63 shows bright rims and filaments, while ic 59 ... | whipping ic 63/ic 59 |
amorphous silicates containing abundant nano-inclusions have been reported in the paris cm chondrite (leroux et al., 2015). they have chemical and morphological similarities to glass with embedded metal and sulfides (gems) found in interplanetary dust particles (idps) and micrometeorites believed to originate from come... | search for meteoritic gems ii: comparison of inclusions in amorphous silicates from the paris chondrite and from anhydrous chondritic interplanetary dust particles |
during 2015 january 9-11, at a heliocentric distance of ∼2.58-2.57 au, the esa rosetta spacecraft resided at a cometocentric distance of ∼28 km from the nucleus of comet 67p/churyumov-gerasimenko, sweeping the terminator at northern latitudes of 43°n-58°n. measurements by the rosetta orbiter spectrometer for ion and ne... | model-observation comparisons of electron number densities in the coma of 67p/churyumov-gerasimenko during january 2015 |
context. on 20 january 2015 the rosetta spacecraft was at a heliocentric distance of 2.5 au, accompanying comet 67p/churyumov-gerasimenko on its journey toward the sun. the ion composition analyser (rpc-ica), other instruments of the rosetta plasma consortium, and the rosina instrument made observations relevant to the... | ion acoustic waves at comet 67p/churyumov-gerasimenko. observations and computations |
in this work we model the dynamical evolution of meteoroid streams of comet 96p/machholz, and the largest member of the marsden sunskirters, comet p/1999 j6. we simultaneously fit the characteristics of eight meteor showers which have been proposed to be linked to the complex, using observations from a range of techniq... | formation and past evolution of the showers of 96p/machholz complex |
polybrominated diphenyl ethers (pbdes) are ubiquitous and prolific contaminant in both the abiotic and biotic environment because of the wide industrial applications of these chemicals. in the present study, the effects of 2,2′,4,4′‑tetrabrominateddiphenyl ether (bde‑47) and 2,2′,4,4′,5,5′‑hexabromodiphenyl ether (bde‑... | hepatic oxidative stress, dna damage and apoptosis in adult zebrafish following sub‑chronic exposure to bde‑47 and bde‑153 |
low-energy ions are difficult to measure, mainly due to spacecraft charging. the ions are attracted to or repelled from the charged surface prior to detection, which changes both the energy and travel direction of the ions. this results in distortions of the data, and the changed travel directions distort the effective... | the influence of varying spacecraft potentials and debye lengths on in situ low-energy ion measurements |
we observe comet c/2019 y4 (atlas) before and after its disintegration while making polarimetric measurements over a wide range of phase angles. the disintegration event was marked with a dramatic growth of the positive polarization branch that is consistent with a large relative abundance of absorbing material of up t... | polarization of disintegrating comet c/2019 y4 (atlas) |
rosetta has detected the presence of the hydrogen halides hf, hcl, and hbr in the coma of comet 67p/churyumov-gerasimenko. these species are known to freeze out on icy grains in molecular clouds. analysis of the abundances of hf and hcl as a function of cometocentric distance suggests that these hydrogen halides are re... | evidence for distributed gas sources of hydrogen halides in the coma of comet 67p/churyumov-gerasimenko |
numerous water-ice-rich deposits surviving more than several months on comet 67p/churyumov-gerasimenko were observed during the rosetta mission. we announce the first-time detection of water-ice features surviving up to 2 yr since their first observation via osiris (optical, spectroscopic, and infrared remote imaging s... | long-term survival of surface water ice on comet 67p |
with the discovery of 1i 'oumuamua and 2i borisov, interstellar objects (isos) have been thrust into the forefront of planetary science, and the robotic exploration of isos is now of significant interest. with current propulsion technology, rendezvous with these objects is likely infeasible, and thus the maximum scienc... | navigation evaluation for fast interstellar object flybys |
on the 12th of november 2014, the rosetta philae lander descended to make the first soft touchdown on the surface of a comet - comet 67p/churyumov-gerasimenko. that soft touchdown did occur but due to the failure in the firing of its two harpoons, philae bounced and travelled across the comet making contact with the su... | the search campaign to identify and image the philae lander on the surface of comet 67p/churyumov-gerasimenko |
we consider the discrete directed polymer model with i.i.d. environment and we study the fluctuations of the tail $n^{(d-2)/4}(w_\infty - w_n)$ of the normalized partition function. it was proven by comets and liu, that for sufficiently high temperature, the fluctuations converge in distribution towards the product of ... | gaussian fluctuations for the directed polymer partition function for $d\\geq 3$ and in the whole $l^2$-region |
aims: we analyze the physical properties and dynamical origin of a curved jet of comet 67p/churyumov-gerasimenko that was observed repeatedly in several nucleus rotations starting on may 30 and persisting until early august, 2015.methods: we simulated the motion of dust grains ejected from the nucleus surface under the... | observations and analysis of a curved jet in the coma of comet 67p/churyumov-gerasimenko |
we present millimetre (submillimeter array) and submillimetre (scuba-2) continuum observations of the peculiar star kic 8462852 which displayed several deep and aperiodic dips in brightness during the kepler mission. our observations are approximately confusion-limited at 850 μm and are the deepest millimetre and submi... | constraints on the circumstellar dust around kic 8462852 |
context. cometary activity affects the orbital motion and rotation state through sublimation-induced forces. the availability of precise rotation-axis orientation and position data from the rosetta mission allows us to accurately determine the outgassing of comet churyumov-gerasimenko/67p (67p).aims: we derived the obs... | outgassing-induced acceleration of comet 67p/churyumov-gerasimenko |
the oort cloud (oc) probably formed more than 4 gyr ago and has been moving with the sun in the galaxy since, exposed to external influences, most prominently to the galactic tide and passing field stars. theories suggest that other stars might possess exocomets distributed similarly to our oc. we study the erosion of ... | capture of exocomets and the erosion of the oort cloud due to stellar encounters in the galaxy |
the propagation of three-dimensional nonlinear dust acoustic waves in a dusty plasma consisting of positive and negative dust grains as well as boltzmann distributed electrons and ions is investigated. using a reductive perturbation method, cylindrical kadomtsev-petviashvili and spherical kadomtsev-petviashvili equatio... | solutions of nonplanar kp-equations for dusty plasma system with ge-method |
six essential oils (from oregano, thyme, clove, lavender, clary sage, and arborvitae) exhibited different antibacterial and antifungal properties. antimicrobial activity was shown against pathogenic (escherichia coli, salmonella typhimurium, yersinia enterocolitica, staphylococcus aureus, listeria monocytogenes, and en... | the antibacterial and antifungal activity of six essential oils and their cyto/genotoxicity to human hel 12469 cells |
context. near- and mid-infrared interferometric observations have revealed populations of hot and warm dust grains populating the inner regions of extrasolar planetary systems. these are known as exozodiacal dust clouds, or exozodis, reflecting the similarity with the solar system's zodiacal cloud. radiative transfer m... | hot exozodiacal dust: an exocometary origin? |
the langmuir probe instrument on rosetta monitored the photoelectron emission current of the probes during the rosetta mission at comet 67p/churyumov-gerasimenko, in essence acting as a photodiode monitoring the solar ultraviolet radiation at wavelengths below 250 nm. we have used three methods of extracting the photoe... | rosetta photoelectron emission and solar ultraviolet flux at comet 67p |
for the second discovered interstellar comet 2i/borisov we searched for a candidate for its home system. we will never be sure which star or stellar system does this comet come from but obtaining a very small relative velocity and a promisingly small miss-distance, when tracing the motion of 2i/borisov back in time in ... | kruger 60 as a home system for 2i/borisov -- a case study |
we present a study of c/2019 y4 (atlas) using sloan gri observations from 2020 mid-january to early april. during this time span, the comet brightened with a growth in the effective cross-section of $\left(2.0\pm 0.1\right)\times {10}^{2}$ m2 s-1 from the beginning to ∼70 days preperihelion in late 2020 march, followed... | observations of disintegrating long-period comet c/2019 y4 (atlas): a sibling of c/1844 y1 (great comet) |
context. in this letter we aim to explore whether gas is also expected in the kuiper belt (kb) in our solar system.aims: to quantify the gas release in our solar system, we use models for gas release that have been applied to extrasolar planetary systems as well as a physical model that accounts for gas released due to... | a molecular wind blows out of the kuiper belt |
we present analysis of ir and optical spectroscopy of jupiter-family comet (jfc) 46p/wirtanen obtained in 2019 january, when the comet had sufficient geocentric velocity to enable studies of the hypervolatiles co and ch4, as well as [o ] emission. these species could not be studied near closest approach in mid-december... | quantifying the hypervolatile abundances in jupiter-family comet 46p/wirtanen |
formation of the first planetesimals remains an unsolved problem. growth by sticking must initiate the process, but multiple studies have revealed a series of barriers that can slow or stall growth, most of them due to nebula turbulence. in a companion paper, we study the influence of these barriers on models of fracta... | global modeling of nebulae with particle growth, drift, and evaporation fronts. iii. redistribution of refractories and volatiles |
we present a comprehensive analysis of the chemical composition of the jupiter-family comet and potential spacecraft target 46p/wirtanen, in the near-ir wavelength range. we used ishell at the nasa infrared telescope facility to observe the comet on 11 pre-, near-, and postperihelion dates in 2018 december and 2019 jan... | comprehensive study of the chemical composition and spatial outgassing behavior of hyperactive comet 46p/wirtanen using near-ir spectroscopy during its historic 2018 apparition |
models of the zodiacal cloud's thermal emission and sporadic meteoroids suggest jupiter-family comets (jfcs) as the dominant source of interplanetary dust. however, comet sublimation is insufficient to sustain the quantity of dust presently in the inner solar system, suggesting that spontaneous disruptions of jfcs may ... | comet fragmentation as a source of the zodiacal cloud |
the standard approach to obtaining knowledge about the properties of the surface layer of a comet from observations of gas production consists of two stages. first, various thermophysical models are used to calculate gas production for a few sets of parameters. second, a comparison of observations and theoretical predi... | cometary surface dust layers built out of millimetre-scale aggregates: dependence of modelled cometary gas production on the layer transport properties |
we quantitatively investigated the hydrogen addition reactions of acetylene (c2h2) and ethylene (c2h4) on amorphous solid water (asw) at 10 and 20 k relevant to the formation of ethane (c2h6) on interstellar icy grains. we found that the asw surface enhances the reaction rates for c2h2 and c2h4 by approximately a facto... | hydrogenation and deuteration of c2h2 and c2h4 on cold grains: a clue to the formation mechanism of c2h6 with astronomical interest |
context. the second gaia data release (gaia dr2) provided us with the precise five-parameter astrometry for 1.3 billion of sources. as stars passing close to the solar system are thought to influence the dynamical history of long-period comets, we update and extend the list of stars that could potentially perturb the m... | a surprise in the updated list of stellar perturbers of long-period comet motion |
we present infrared telescope facility/spex and neowise observations of the dynamically new comet c/2013 us10 (catalina), hereafter us10, from 5.8 au inbound, to near perihelion at 1.3 au, and back to 5.0 au outbound. we detect water ice in the coma of us10, assess and monitor the physical properties of the ice as inso... | icy grains from the nucleus of comet c/2013 us10 (catalina) |
agglomerated debris particles are realistic model cosmic dust particles that reproduce their highly irregular and fluffy morphology. we compute the absolute magnitude of these model particles in the broad-band filters b, v, r, and i from the widely used johnson-cousins photometric system. these data are aimed at provid... | absolute magnitude of small cosmic dust particles |
we investigate the thermal evolution of comet 67p/churyumov-gerasimenko’s subsurface in the seth_01 region, where active pits have been observed by the esa/rosetta mission. our simulations show that clathrate destabilization and amorphous ice crystallization can occur at depths corresponding to those of the observed pi... | pits formation from volatile outgassing on 67p/churyumov-gerasimenko |
an interdisciplinary review of the chemical literature that points to a unifying scenario for the origin of life, referred to as the primordial multifunctional organic entity (prime) scenario, is provided herein. in the prime scenario it is suggested that the insoluble organic matter (iom) in carbonaceous chondrites, a... | insoluble organic matter in chondrites: archetypal melanin-like pah-based multifunctionality at the origin of life? |
we investigate the generation of waves in the lower hybrid frequency range by density gradients in the near plasma environment of comet 67p/churyumov-gerasimenko. when the plasma is dominated by water ions from the comet, a situation with magnetized electrons and unmagnetized ions is favourable for the generation of lo... | lower hybrid waves at comet 67p/churyumov-gerasimenko |
we related morphological (size/shape) and dynamical properties of the dust ejected from the 67p/churyumov-gerasimenko comet by combining data from two instruments onboard the esa's rosetta mission, i.e. the midas atomic force microscope and the giada dust detector. the two instruments detected dust of different size (1... | combining rosetta's giada and midas data: morphological versus dynamical properties of dust at 67p/churyumov-gerasimenko |
we examined the al-mg isotope systematics of plagioclase in a feo-poor ferromagnesian wild 2 particle (c2092,7,81,1,0; named pyxie) using a ∼2 μm spot. three analyses show average 27al/24mg ratio of ∼65 and excess δ26mg* value of + 0.1 ± 4.5 ‰ (2σ), indicating no resolvable 26mg excess in the particle. the inferred ini... | late formation of a comet wild 2 crystalline silicate particle, pyxie, inferred from al-mg chronology of plagioclase |
we study the dynamical properties of objects in hyperbolic orbits passing through the inner solar system in the context of two different potential sources: interstellar space and the oort cloud. we analytically derive the probability distributions of eccentricity, e, and perihelion distance, q, for each source and esti... | hyperbolic orbits in the solar system: interstellar origin or perturbed oort cloud comets? |
the bulk density of a meteoroid affects its dynamics in space, its ablation in the atmosphere, and the damage it does to spacecraft and lunar or planetary surfaces. meteoroid bulk densities are also notoriously difficult to measure, and we are typically forced to assume a density or attempt to measure it via a proxy. i... | a two-population sporadic meteoroid bulk density distribution and its implications for environment models |
a number of planetary spacecraft missions have carried instruments with sensors covering the ultraviolet (uv) wavelength range. however, there exists a general lack of relevant uv reflectance laboratory data to compare against these planetary surface remote sensing observations in order to make confident material ident... | ultraviolet spectral reflectance of carbonaceous materials |
the centaurs are the small solar system bodies intermediate between the active inner solar system jupiter family comets and their inactive progenitors in the trans-neptunian region. among the fraction of centaurs which show comet-like activity, 174p/echeclus is best known for its massive 2005 outburst in which a large ... | physical characterization of the 2017 december outburst of the centaur 174p/echeclus |
the presence of n2 in the surface environment of pluto is critical in creating pluto's richness of features and processes. here, we propose that the nitrogen atoms in the n2 observed on pluto were accreted in that chemical form during the formation of pluto. we use new horizons data and models to estimate the amounts o... | primordial n2 provides a cosmochemical explanation for the existence of sputnik planitia, pluto |
context. accurate hydrogen spectra emitted by the entire solar disc in the ly-α and ly-βlines are valuable for deriving the distribution and the behaviour of atomic hydrogen in the heliosphere, for understanding the uv emissions of solar type stars better, and finally for estimating the solar energy input that mainly i... | hydrogen ly-α and ly-β full sun line profiles observed with sumer/soho (1996-2009) |
amorphous solid water (asw) is found on icy dust grains in the interstellar medium (ism), as well as on comets and other icy objects in the outer solar system. the optical properties of asw are thus relevant for many astrophysical environments, but in the ultraviolet-visible (uv-vis), its refractive index is not well c... | the refractive index of amorphous and crystalline water ice in the uv-vis |
context. the rosetta spacecraft escorted comet 67p/churyumov-gerasimenko for 2 yr along its journey through the solar system between 3.8 and 1.24 au. thanks to the high resolution mass spectrometer on board rosetta, the detailed ion composition within a coma has been accurately assessed in situ for the very first time.... | rosina ion zoo at comet 67p |
we present high resolution, deep imaging of interstellar comet 2i/borisov taken with the hubble space telescope/wide field camera 3 (hst/wfc3) on 2019 december 8 utc and 2020 january 27 utc (hst go 16040, pi: bolin) before and after its perihelion passage in combination with hst/wfc3 images taken on 2019 october 12 utc... | constraints on the spin-pole orientation, jet morphology, and rotation of interstellar comet 2i/borisov with deep hst imaging |
we present the results of the photometric and spectrophotometric properties of the 67p/churyumov-gerasimenko nucleus derived with the optical, spectroscopic and infrared remote imaging system instrument during the closest fly-by over the comet, which took place on 2015 february 14 at a distance of ∼6 km from the surfac... | decimetre-scaled spectrophotometric properties of the nucleus of comet 67p/churyumov-gerasimenko from osiris observations |
we report on our extensive photometry and imaging of comet 46p/wirtanen during its 2018/19 apparition and use these data to constrain the modeling of wirtanen's activity. narrowband photometry was obtained in 9 epochs from 2018 october through 2019 march as well as 10 epochs during the 1991, 1997, and 2008 apparitions.... | narrowband observations of comet 46p/wirtanen during its exceptional apparition of 2018/19. ii. photometry, jet morphology, and modeling results |
context. as the esa rosetta mission approached, orbited, and sent a lander to comet 67p/churyumov-gerasimenko in 2014, a large campaign of ground-based observations also followed the comet.aims: we constrain the total activity level of the comet by photometry and spectroscopy to place rosetta results in context and to ... | distant activity of 67p/churyumov-gerasimenko in 2014: ground-based results during the rosetta pre-landing phase |
there has been growing observational evidence for the presence of condensates in the atmospheres and/or comet-like tails of extrasolar planets. as a result, systematic and homogeneous tables of dust properties are useful in order to facilitate further observational and theoretical studies. in this paper we present calc... | tables of phase functions, opacities, albedos, equilibrium temperatures, and radiative accelerations of dust grains in exoplanets |
we present an intensive monitoring of high-resolution spectra of the ca ii k line in the a7iv shell star φ leo at very short (minutes, hours), short (night to night), and medium (weeks, months) timescales. the spectra show remarkable variable absorptions on timescales of hours, days, and months. the characteristics of ... | exocomet signatures around the a-shell star φ leonis? |
comets are usually considered to be the most primitive bodies in the solar system. the level of truth of this paradigm, however, is a matter of debate, especially if by primitive we mean that they represent a sample of intact, unprocessed material. we now have the possibility of analysing the comet 67p/churyumov-gerasi... | how pristine is the interior of the comet 67p/churyumov-gerasimenko? |
we study how uncertainties in knowledge of the microstructure of the porous dust surface layer affect our estimates of effective gas production of comet 67p/churyumov-gerasimenko. we analyse the transport properties (distribution of free paths, mean pore size, permeability) for random densely packed porous layers. bimo... | the effect of varying porosity and inhomogeneities of the surface dust layer on the modelling of comet gas production |
comets are considered the most primitive planetary bodies in our solar system, i.e., they should have best preserved the solid components of the matter from which our solar system formed. esa's recent rosetta mission to jupiter family comet 67p/churyumov-gerasimenko (67p/cg) has provided a wealth of isotope data which ... | presolar isotopic signatures in meteorites and comets: new insights from the rosetta mission to comet 67p/churyumov-gerasimenko |
we present 2d hydrodynamical simulations of the transition of a protoplanetary nebula (ppn) to a planetary nebula for central stars in binary systems that have undergone a common-envelope event. after 1000 yr of magnetically driven dynamics (ppn phase), a line-driven stellar wind is introduced into the computational do... | common-envelope shaping of planetary nebulae - iv. from protoplanetary to planetary nebula |
we have carried out very large array imaging and a fermi timing analysis of the 115 ms γ-ray and radio pulsar psr j0002+6216. we found that the pulsar lies at the apex of a narrowly collimated cometary-like 7‧ tail of nonthermal radio emission, which we identify as a bow-shock pulsar wind nebula. the tail of the nebula... | the tail of psr j0002+6216 and the supernova remnant ctb 1 |
the plasma around comet 67p/churyumov-gerasimenko showed remarkable variability throughout the entire rosetta mission. plasma boundaries such as the diamagnetic cavity, solar wind ion cavity and infant bow shock separate regions with distinct plasma parameters from each other. here, we focus on a particular feature in ... | warm protons at comet 67p/churyumov-gerasimenko - implications for the infant bow shock |
context. we present a new numerical model of the η-aquariid and orionid meteor showers.aims: the model investigates the origin, variability, and age of the η-aquariid and orionid apparitions from 1985 to the present day in order to forecast their activity over the next several decades.methods: through the numerical int... | modeling the past and future activity of the halleyid meteor showers |
high-resolution bathymetry collected with an autonomous underwater vehicle (auv) along the flanks of three ridges of the accretionary prism offshore southwestern (sw) taiwan revealed more than 650 elongated depressions in water depths ranging from 1155 to 1420 m. the depressions are between 12 and 129 m long, 5 to 70 m... | discovery of numerous pingos and comet-shaped depressions offshore southwestern taiwan |
iron oxide-fe2o3 nanoparticles-nps and microparticles-mps widely used in medical applications were comparatively investigated for in vitro mutagenicity and in vivo cytotoxicity/genotoxicity using the ames test in salmonella typhimurium strains (125, 250, 500, 750, 1,000 µg/ml) and chromosome aberration/comet assays in ... | comparative investigation of iron oxide nanoparticles and microparticles using the in vitro bacterial reverse mutation and in vivo allium chromosome aberration and comet assays |
the rosetta spacecraft made a rendezvous with comet 67p/churyumov-gerasimenko (67p) in 2014 august, soon after the philae module landed on the small lobe of the nucleus on 2014 november 12. the consert instrument, onboard rosetta and philae, sounded the upper part of the interior of 67p with radiowaves at 90 mhz and de... | a porosity gradient in 67p/c-g nucleus suggested from consert and sesame-pp results: an interpretation based on new laboratory permittivity measurements of porous icy analogues |
we report the first infrared study of the low-energy (<20 ev) electron-induced reactions of condensed methanol. our goal is to simulate processes which occur when high-energy cosmic rays interact with interstellar and cometary ices, where methanol, a precursor of several prebiotic species, is relatively abundant. th... | low-energy (<20 ev) and high-energy (1000 ev) electron-induced methanol radiolysis of astrochemical interest |
the paper presents a new method for determining the change in the brightness of a comet during an outburst in which particles are ejected into the coma at a uniform rate, i.e. via a long-lived jet. in the proposed approach, the mass flow rate by a jet and the time it takes to increase the brightness of the comet play k... | the rise time of the change of cometary brightness during its outburst |
the cophylab (cometary physics laboratory) project is designed to study the physics of comets through a series of earth-based experiments. for these experiments, a dust analogue was created with physical properties comparable to those of the non-volatile dust found on comets. this 'cophylab dust' is planned to be mixed... | cometary dust analogues for physics experiments |
the coma and the comet-solar wind interaction of comet 67p/churyumov-gerasimenko changed dramatically from the initial rosetta spacecraft encounter in 2014 august through perihelion in 2015 august. just before equinox (at 1.6 au from the sun), the solar wind signal disappeared and two regions of different cometary ion ... | ion chemistry in the coma of comet 67p near perihelion |
the inner structure of icy moons comprises ices, liquid water, a silicate rocky core and sometimes an inner metallic core depending on thermal evolution and differentiation. mineralogy and density models for the silicate part of the icy satellites cores were assessed assuming a carbonaceous chondritic (ci) bulk composi... | a carbonaceous chondrite and cometary origin for icy moons of jupiter and saturn |
residues of anti-neoplastic drugs represent new and emerging pollutants in aquatic environments. many of these drugs are genotoxic, and it has been postulated that they can cause adverse effects in aquatic ecosystems. 5-fluorouracil (5-fu) is one of the most extensively used anti-neoplastic drugs in cancer therapy, and... | assessment of toxicity and genotoxicity of low doses of 5-fluorouracil in zebrafish (danio rerio) two-generation study |
the astropause (heliopause for the sun) is the tangential discontinuity separating the stellar wind from the interstellar plasma. the global shape of the heliopause is a matter of debates. two types of the shape are under discussion: comet-like and tube-like. in the second type, the two-jets oriented towards the stella... | new unexpected flow patterns in the problem of the stellar wind interaction with the interstellar medium: stationary ideal-mhd solutions |
the astronomical detection of formamide (nh2cho) toward various star-forming regions and in cometary material implies that the simplest amide might have an early origin in dark molecular clouds at low temperatures. laboratory studies have proven the efficient nh2cho formation in interstellar co:nh3 ice analogs upon ene... | formation of the simplest amide in molecular clouds: formamide (nh2cho) and its derivatives in h2o-rich and co-rich interstellar ice analogs upon vuv irradiation |
gliese 710 is a k7v star located 19 pc from the sun in the constellation of serpens cauda, which is headed straight for the solar system. berski & dybczynski (2016) used data from gaia dr1 to show that this star will be 13366 au from the sun in 1.35 myr from now. here, we present an independent confirmation of this... | an independent confirmation of the future flyby of gliese 710 to the solar system using gaia dr2 |
evidence in radar, reflectance, and visible imagery indicates that surface and subsurface water ice is present inside permanently shadowed regions in the north polar region of mercury. the origin of this ice and the time at which it was delivered to the planet are both unknown. finding the smallest, most easily eroded ... | ice in micro cold traps on mercury: implications for age and origin |
methyl isocyanate (ch3nco) is one of the important complex organic molecules detected on the comet 67p/churyumov-gerasimenko by rosetta's philae lander. it was also detected in hot cores around high-mass protostars along with a recent detection in the solar-type protostar iras 16293-2422. we propose here a gas-grain ch... | methyl isocyanate (ch3nco): an important missing organic in current astrochemical networks |
climate change due to global warming can alter the salinity and ph in aquatic ecosystems. low salinity (ls) and ocean acidification (oa) are stressors involved in osmotic regulation and can alter the antioxidant capacity of the body. in this study, we observed na+/k+-atpase (nka) expression and activity in disk abalone... | short-term exposure to combined condition of low salinity and ph affects ros-mediated stress in disk abalone (haliotis discus hannai) |
the nuclear-spin chemistry of interstellar water is investigated using the university of grenoble alpes astrochemical network (ugan). this network includes reactions involving the different nuclear-spin states of the hydrides of carbon, nitrogen, oxygen, and sulphur, as well as their deuterated forms. nuclear-spin sele... | the ortho-to-para ratio of water in interstellar clouds |
the hdo/h2o ratio measured in interstellar gas is often used to draw conclusions on the formation and evolution of water in star-forming regions and, by comparison with cometary data, on the origin of water on earth. in cold cores and in the outer regions of protoplanetary disks, an important source of gas-phase water ... | photodesorption of h2o, hdo, and d2o ice and its impact on fractionation |
around the time of its perihelion passage, the observability of 67p/churyumov-gerasimenko from earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. the peak in the comet's activity was therefore difficult to observe with conventionally scheduled telesco... | the perihelion activity of comet 67p/churyumov-gerasimenko as seen by robotic telescopes |
context. during september and october 2014, the osiris cameras onboard the esa rosetta mission detected millions of single particles. many of these dust particlesappear as long tracks (due to both the dust proper motion and the spacecraft motion during the exposure time) with a clear brightness periodicity.aims: we int... | rotating dust particles in the coma of comet 67p/churyumov-gerasimenko |
although a merging galaxy cluster is a useful laboratory to study many important astrophysical processes and fundamental physics, only limited interpretations are possible without careful analysis of the merger scenario. however, the study is demanding because a thorough comparison of multiwavelength observations with ... | reconstruction of radio relics and x-ray tails in an off-axis cluster merger: hydrodynamical simulations of a115 |
aims: interstellar objects passing through our solar system offer a rare opportunity to probe the physical and chemical processes involved in solid body and planet formation in extrasolar systems. the main objective of our study is to search for diagnostic absorption features of water ice in the near-infrared (nir) spe... | searching for water ice in the coma of interstellar object 2i/borisov |
context. the optical properties of the second generation dust that we observe in debris disks remain quite elusive, whether it is the absorption efficiencies at millimeter wavelengths or the (un)polarized phase function at near-infrared wavelengths. thankfully, the same particles are experiencing forces that are size d... | the halo around hd 32297: μm-sized cometary dust |
in this chapter, we explore the origins of cometary material and discuss the clues cometary composition provides in the context of the origin of our solar system. the review focuses on both cometary refractory and volatile materials, which jointly provide crucial information about the processes that shaped the solar sy... | interstellar heritage and the birth environment of the solar system |
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