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in recent years, gas has been observed in an increasing number of debris discs, though its nature remains to be determined. here, we analyse co molecular excitation in optically thin debris discs, and search atacama large millimeter/submillimeter array (alma) cycle-0 data for co j = 3-2 emission in the fomalhaut ring. ... | co mass upper limits in the fomalhaut ring - the importance of nlte excitation in debris discs and future prospects with alma |
in the advent of the rosetta arrival at the comet 67p/churyumov-gerasimenko, we present a global 3d hybrid simulation model of the cometary plasma interaction which resolves the innermost coma sufficiently. as rosetta will only provide local information, global simulations are required to put these local observations i... | dynamical features and spatial structures of the plasma interaction region of 67p/churyumov-gerasimenko and the solar wind |
one of the primary objectives of the rosetta plasma consortium, a suite of five plasma instruments on-board the rosetta spacecraft, is to observe the formation and evolution of plasma interaction regions at the comet 67p/churyumov-gerasimenko (67p/cg). observations made between 2015 april and 2016 february show that so... | rpc observation of the development and evolution of plasma interaction boundaries at 67p/churyumov-gerasimenko |
context. studying the coma environment of comet 67p/churyumov-gerasimenko (67p) is one of the primary scientific goals of the virtis experiment on the esa rosetta mission.aims: the distribution and variability of water vapour and carbon dioxide in the comet's coma are needed to estimate their production rate, abundance... | water and carbon dioxide distribution in the 67p/churyumov-gerasimenko coma from virtis-m infrared observations |
interstellar boundary explorer (ibex) measurements of energetic neutral atoms (enas) from the heliotail show a multi-lobe structure of ena fluxes as a function of energy between ∼0.71 and 4.29 kev. below ∼2 kev, there is a single structure of enhanced ena fluxes centered near the downwind direction. above ∼2 kev, this ... | structure of the heliotail from interstellar boundary explorer observations: implications for the 11-year solar cycle and pickup ions in the heliosheath |
in this work, we present results that simultaneously constrain the dust size distribution, dust-to-gas ratio, fraction of dust re-deposition, and total mass production rates for comet 67p/churyumov-gerasimenko. we use a 3d direct simulation monte carlo (dsmc) gas dynamics code to simulate the inner gas coma of the come... | the dust-to-gas ratio, size distribution, and dust fall-back fraction of comet 67p/churyumov-gerasimenko: inferences from linking the optical and dynamical properties of the inner comae. |
in the last few years, multiwavelength observations have revealed the ubiquity of gaps/rings in circumstellar discs. here we report the first alma observations of hd 92945 at 0.86 mm, which reveal a gap at about 73 ± 3 au within a broad disc of planetesimals that extends from 50 to 140 au. we find that the gap is 20^{+... | a gap in hd 92945's broad planetesimal disc revealed by alma |
we present an investigation of the emission intensity of co2 and h2o and their distribution in the coma of 67p/ churyumov-gerasimenko obtained by the virtis-m imaging spectrometer on the rosetta mission. we analyze 4 data cubes from feb. 28, and 7 data cubes from april 27, 2015. for both data sets the spacecraft was at... | investigation into the disparate origin of co2 and h2o outgassing for comet 67/p |
the rosetta mission provided detailed observations of the growth of a cavity in the solar wind around comet 67p/churyumov-gerasimenko. as the comet approached the sun, the plasma of cometary origin grew enough in density and size to present an obstacle to the solar wind. our results demonstrate how the initial slight p... | the birth and growth of a solar wind cavity around a comet - rosetta observations |
the environment of a comet is a fascinating and unique laboratory to study plasma processes and the formation of structures such as shocks and discontinuities from electron scales to ion scales and above. the european space agency's rosetta mission collected data for more than two years, from the rendezvous with comet ... | the plasma environment of comet 67p/churyumov-gerasimenko |
the rosetta orbiter spectrometer for ion and neutral analysis (rosina) suite of instruments operated throughout the over two years of the rosetta mission operations in the vicinity of comet 67p/churyumov-gerasimenko. it measured gas densities and composition throughout the comet's atmosphere, or coma. here we present t... | the surface distributions of the production of the major volatile species, h2o, co2, co and o2, from the nucleus of comet 67p/churyumov-gerasimenko throughout the rosetta mission as measured by the rosina double focusing mass spectrometer |
solar wind turbulence within high-speed streams is reviewed from the point of view of embedded single nonlinear alfvén wave cycles, discontinuities, magnetic decreases (mds), and shocks. for comparison and guidance, cometary plasma turbulence is also briefly reviewed. it is demonstrated that cometary nonlinear magnetos... | a review of alfvénic turbulence in high-speed solar wind streams: hints from cometary plasma turbulence |
many existing optical meteor trajectory estimation methods use the approximation that the velocity of the meteor at the beginning of its luminous phase is equivalent to its velocity before atmospheric entry. meteoroid kinetic energy loss prior to the luminous phase cannot be measured, but for some masses and entry geom... | modelling the measurement accuracy of pre-atmosphere velocities of meteoroids |
the role of radiation pressure in shaping exoplanet photoevaporation remains a topic of contention. radiation pressure from the exoplanet's host star has been proposed as a mechanism to drive the escaping atmosphere into a 'cometary' tail and explain the high velocities observed in systems where mass-loss is occurring.... | effects of radiation pressure on the evaporative wind of hd 209458b |
when viewed from earth, most of what we observe of a comet is dust. the influence of solar radiation pressure on the trajectories of dust particles depends on their cross-section to mass ratio. hence solar radiation pressure acts like a mass spectrometer inside a cometary tail. the appearances of cometary dust tails ha... | dust emission and dynamics |
alignment of dust grains in astrophysical environments results in the polarization of starlight as well as the polarization of radiation emitted by dust. we demonstrate the advances in grain alignment theory that allow the use of linear and circular polarization to probe not only the magnetic field, but also dust compo... | magnetic properties of dust grains, effect of precession, and radiative torque alignment |
we present hubble space telescope observations of a photometric outburst and splitting event in interstellar comet 2i/borisov. the outburst, first reported with the comet outbound at ∼2.8 au, was caused by the expulsion of solid particles having a combined cross section ∼100 km2 and a mass in 0.1 mm sized particles ∼2 ... | outburst and splitting of interstellar comet 2i/borisov |
optical observations of the oort cloud comet c/2017 k2 (panstarrs) show that its activity began at large heliocentric distances (up to 35 au), which cannot be explained by either the sublimation or the crystallization of water ice. supervolatile sublimation, most likely of carbon monoxide (co), has been proposed as a p... | discovery of carbon monoxide in distant comet c/2017 k2 (panstarrs) |
1i/'oumuamua (or 1i) and 2i/borisov (or 2i), the first interstellar objects (isos) discovered passing through the solar system, have opened up entirely new areas of exobody research. finding additional isos and planning missions to intercept or rendezvous with these bodies will greatly benefit from knowledge of their l... | interstellar objects in the solar system: 1. isotropic kinematics from the gaia early data release 3 |
a large quantity of ch4 is emitted to the atmosphere via ventilation shafts of underground coal mines. according to the european pollutant release and transfer register (e-prtr), hard coal mines in the upper silesia coal basin (uscb) are a strong contributor (447 kt ch4 in 2017) to the annual european ch4 emissions. ho... | quantifying methane emissions from coal mining ventilation shafts using an unmanned aerial vehicle (uav)-based active aircore system |
the rosetta spacecraft has escorted comet 67p/churyumov-gerasimenko since 6 august 2014 and has offered an unprecedented opportunity to study plasma physics in the coma. we have used this opportunity to make the first characterization of cometary electrons with kappa distributions. two three-dimensional kappa functions... | characterizing cometary electrons with kappa distributions |
using a 3d fully kinetic approach, we disentangle and explain the ion and electron dynamics of the solar wind interaction with a weakly outgassing comet. we show that, to first order, the dynamical interaction is representative of a four-fluid coupled system. we self-consistently simulate and identify the origin of the... | electron and ion dynamics of the solar wind interaction with a weakly outgassing comet |
context. unlike all previous cometary space missions, the rosetta spacecraft accompanied its target, comet 67p/churyumov-gerasimenko, for more than two years on its way around the sun. thereby, an unexpected diversity and complexity of the chemical composition was revealed.aims: our first step of decrypting the exact c... | aliphatic and aromatic hydrocarbons in comet 67p/churyumov-gerasimenko seen by rosina |
the european space agency's spacecraft rosetta has reached its final destination, comet 67p/churyumov-gerasimenko. whilst orbiting in the close vicinity of the nucleus the rosetta magnetometers detected a new type of low-frequency wave possibly generated by a cross-field current instability due to freshly ionized comet... | two-point observations of low-frequency waves at 67p/churyumov-gerasimenko during the descent of philae: comparison of rpcmag and romap |
chondritic porous interplanetary dust particles (cp idps) collected in the stratosphere are regarded as possibly being cometary dust, and are therefore the most primitive solar system material that is currently available for analysis in laboratories. in this paper we report the discovery of more than 40 chondritic poro... | cometary dust in antarctic ice and snow: past and present chondritic porous micrometeorites preserved on the earth's surface |
the optical, spectroscopic, and infrared remote imaging system (osiris) experiment onboard the rosetta spacecraft currently orbiting comet 67p/churyumov-gerasimenko has yielded unprecedented views of a comet's nucleus. we present here the first ever observations of meter-scale fractures on the surface of a comet. some ... | fractures on comet 67p/churyumov-gerasimenko observed by rosetta/osiris |
the apparition of bright comets c/2012 f6 (lemmon) and c/2014 q2 (lovejoy) in march-april 2013 and january 2015, combined with the improved observational capabilities of submillimeter facilities, offered an opportunity to carry out sensitive compositional and isotopic studies of the volatiles in their coma. we observed... | isotopic ratios of h, c, n, o, and s in comets c/2012 f6 (lemmon) and c/2014 q2 (lovejoy) |
complex organic molecules (coms) can be produced by energetic processing of interstellar ice mantles accreted on top of dust grains. two coms with proposed energetic ice formation pathways are formamide and acetaldehyde. both have been detected in solar system comets and in different circumstellar and interstellar envi... | formation of nh2cho and ch3cho upon uv photoprocessing of interstellar ice analogs |
the composition of comets in the solar system comes in multiple groups thought to encode information about their formation in different regions of the outer protosolar disk. the recent discovery of the second interstellar object, 2i/borisov, allows for spectroscopic investigations into its gas content and a preliminary... | carbon chain depletion of 2i/borisov |
we review multiwavelength properties of pulsar wind nebulae created by supersonically moving pulsars and the effects of pulsar motion on the pulsar wind nebulae morphologies and the ambient medium. supersonic pulsar wind nebulae are characterized by bow-shaped shocks around the pulsar and/or cometary tails filled with ... | pulsar wind nebulae created by fast-moving pulsars |
on 2016 feb 19, nine rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67p/churyumov-gerasimenko. among these instruments were cameras and spectrometers ranging from uv over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collecto... | the 2016 feb 19 outburst of comet 67p/cg: an esa rosetta multi-instrument study |
we present the discovery of seven new proplyds (i.e., sources surrounded by cometary hα emission characteristic of offset ionization fronts (ifs)) in ngc 1977, located about 30‧ north of the orion nebula cluster (onc) at a distance of ∼400 pc. each of these proplyds is situated at projected distances 0.04-0.27 pc from ... | proplyds around a b1 star: 42 orionis in ngc 1977 |
multi-unit spectroscopic explorer (muse) observations of the cluster of galaxies cgr32 (m200 ≃ 2 × 1014 m⊙) at z = 0.73 reveal the presence of two massive star-forming galaxies with extended tails of diffuse gas detected in the [o ii]λλ3727-3729 å emission-line doublet. the tails, which have a cometary shape with a typ... | evidence for ram-pressure stripping in a cluster of galaxies at z = 0.7 |
an important tracer of the origin and evolution of cometary ices is the comparison with ices found in dense clouds and toward young stellar objects (ysos). we present a survey of ices in the 2-5 μm spectra of 23 massive ysos, taken with the nasa infrared telescope facility spex spectrometer. the 4.90 μm absorption band... | survey of ices toward massive young stellar objects. i. ocs, co, ocn-, and ch3oh |
questions regarding how primordial or pristine the comets of the solar system are have been an ongoing controversy. in this review, we describe comets' physical evolution from dust and ice grains in the solar nebula to the contemporary small bodies in the outer solar system. this includes the phases of dust agglomerati... | formation of comets |
close encounters of stars to the sun could affect life on earth through gravitational perturbations of comets in the oort cloud or exposure to ionizing radiation. by integrating orbits through the galactic potential, i identify which of 33 million stars in gaia dr3 with complete phase space information come close to th... | stars that approach within one parsec of the sun: new and more accurate encounters identified in gaia data release 3 |
context. the esa rosetta spacecraft has been orbiting the nucleus of comet 67p/churyumov-gerasimenko since august 2014. the rotation axis of the irregularly shaped nucleus has a large obliquity (52°) and is oriented such that the southern hemisphere is insolated during perihelion.aims: we calculate the change in the ro... | the changing rotation period of comet 67p/churyumov-gerasimenko controlled by its activity |
rosetta and philae have been in hibernation until january 20, 2014. after the successful wakeup they underwent a post-hibernation commissioning. the orbiter instruments (like e.g. the osiris cameras, virtis, miro, alice and rosina) characterized the target comet and its environment to allow landing site selection and t... | rosetta lander - philae: landing preparations |
the esa's comet chaser rosetta has monitored the evolution of the ionized atmosphere of comet 67p/churyumov-gerasimenko (67p/cg) and its interaction with the solar wind, during more than 2 yr. around perihelion, while the cometary outgassing rate was highest, rosetta crossed hundreds of unmagnetized regions, but did no... | diamagnetic region(s): structure of the unmagnetized plasma around comet 67p/cg |
dust-acoustic (da) solitary and periodic waves investigations were performed in a magnetized self-gravitating dusty plasma consisting of negatively and positively charged dust grains in the presence of inertialess ions and electrons. the korteweg-de vries-burger (kdvb) equation has been derived. the numerical investiga... | dust-acoustic solitary and periodic waves in magnetized self-gravito-electrostatic opposite polarity dusty plasmas |
knowledge of the surface temperature distribution on a comet's nucleus and its temporal evolution at different timescales is key to constraining its thermophysical properties and understanding the physical processes that take place at and below the surface. here we report on time-resolved maps of comet 67p/churyumov-ge... | the changing temperature of the nucleus of comet 67p induced by morphological and seasonal effects |
in 2017, 2018, and 2019, comets 46p/wirtanen, 45p/honda-mrkos-pajdusakova, and 41p/tuttle-giacobini-kresak all had perihelion passages. their hydrogen comae were observed by the solar wind anisotropies (swan) all-sky hydrogen lyα camera on the solar and heliospheric observer (soho) satellite: comet 46p for the fourth t... | comet 41p/tuttle-giacobini-kresak, 45p/honda-mrkos-pajdusakova, and 46p/wirtanen: water production activity over 21 yr with soho/swan |
context. early measurements of rosetta's target comet, 67p/churyumov-gerasimenko (67p), showed a strongly heterogeneous coma in h2o, co, and co2.aims: the purpose of this work is to further investigate the coma heterogeneity of 67p, and to provide predictions for the near-perihelion outgassing profile based on the prop... | composition-dependent outgassing of comet 67p/churyumov-gerasimenko from rosina/dfms. implications for nucleus heterogeneity? |
context. isotopic abundances in comets are key to understanding and reconstructing the history and origin of material in the solar system. data for deuterium-to-hydrogen (d/h) ratios in water are available for several comets. however, no long-term studies of the d/h ratio in water of a comet during its passage around t... | high d/h ratios in water and alkanes in comet 67p/churyumov-gerasimenko measured with rosetta/rosina dfms |
in this study, afm1 toxicity and the protective role of trans-resveratrol (t-rsv) against this toxicity were investigated with the help of multiple parameters in albino mice. as a result, afm1 (16 mg/kg b.w) administration caused a decrease in body, kidney and liver weights. this reduction was associated with a decreas... | toxicity mechanisms of aflatoxin m1 assisted with molecular docking and the toxicity-limiting role of trans-resveratrol |
context. osiris, the scientific imaging system onboard the esa rosetta spacecraft, has been imaging the nucleus of comet 67p/churyumov-gerasimenko and its dust and gas environment since march 2014. the images serve different scientific goals, from morphology and composition studies of the nucleus surface, to the motion... | scientific assessment of the quality of osiris images |
1i/’oumuamua is the first interstellar interloper to have been detected. because planetesimal formation and ejection of predominantly icy objects are common by-products of the star and planet formation processes, in this study we address whether 1i/’oumuamua could be representative of this background population of ejec... | origin of 1i/’oumuamua. i. an ejected protoplanetary disk object? |
millimeter observations of co gas in planetesimal belts show a high detection rate around a stars, but few detections for later type stars. we present the first co detection in a planetesimal belt around an m star, twa 7. the optically thin co (j = 3-2) emission is colocated with previously identified dust emission fro... | on the ubiquity and stellar luminosity dependence of exocometary co gas: detection around m dwarf twa 7 |
we introduce a new technique to estimate the comet nuclear size frequency distribution (sfd) that combines a cometary activity model with a survey simulation and apply it to 150 long period comets (lpc) detected by the pan-starrs1 near-earth object survey. the debiased lpc size-frequency distribution is in agreement wi... | the orbit and size-frequency distribution of long period comets observed by pan-starrs1 |
most models of volatile delivery to accreting terrestrial planets assume that the carriers for water are similar in water content to the carbonaceous chondrites in our solar system. here we consider how the water content of planetesimals may be higher in many planetary systems, as they could lack the short-lived radion... | volatile delivery to planets from water-rich planetesimals around low mass stars |
long and short-term exposure to atmospheric particulate matter (pm) has detrimental effects on human health. the effective mechanisms leading to pm toxicity are still not fully understood, even if it is known that physical-chemical properties, strongly influenced by sources and atmospheric processes, are known to play ... | oxidative potential, cytotoxicity, and intracellular oxidative stress generating capacity of pm10: a case study in south of italy |
cometary nuclei imaged from flyby and rendezvous spacecraft show common evidence of layered structures and bilobed shapes. but how and when these features formed is much debated, with distinct implications for solar system formation, dynamics, and geology. we show that these features could be a direct result of accreti... | the shape and structure of cometary nuclei as a result of low-velocity accretion |
we review our current knowledge of comet 67p/churyumov-gerasimenko nucleus composition as inferred from measurements made by remote sensing and in-situ instruments aboard rosetta orbiter and philae lander. spectrophotometric properties (albedos, color indexes and hapke parameters) of 67p/cg derived by rosetta are discu... | comet 67p/cg nucleus composition and comparison to other comets |
1i/’oumuamua is the first detected interstellar interloper. we test the hypothesis that it is representative of a background population of exo-oort cloud objects ejected under the effect of post-main sequence mass loss and stellar encounters. we do this by comparing the cumulative number density of interstellar objects... | origin of 1i/’oumuamua. ii. an ejected exo-oort cloud object? |
we present multiwavelength, ground-based follow-up photometry of the white dwarf wd 1145+017, which has recently been suggested to be orbited by up to six or more short-period, low-mass, disintegrating planetesimals. we detect nine significant dips in flux of between 10% and 30% of the stellar flux in our ∼32 hr of pho... | multiwavelength transit observations of the candidate disintegrating planetesimals orbiting wd 1145+017 |
the solar wind anisotropies (swan) instrument on the solar and heliospheric observatory (soho) satellite has observed 44 long period and new oort cloud comets and 36 apparitions of 17 short period comets since its launch in december 1995. water production rates have been determined from the over 3700 images producing a... | a survey of water production in 61 comets from soho/swan observations of hydrogen lyman-alpha: twenty-one years 1996-2016 |
knowledge of the mechanical properties of protoplanetary and cometary matter is of key importance to better understand the activity of comets and the early stages of planet formation. the tensile strength determines the required pressure to lift off grains, pebbles, and agglomerates from the cometary surface and also d... | sticky or not sticky? measurements of the tensile strength of microgranular organic materials |
in a previous work [asymptotically quasiperiodic solutions for time-dependent hamiltonians, arxiv preprint arxiv:2211.06623 (2022)], we consider time-dependent perturbations of a hamiltonian vector field having an invariant torus supporting quasiperiodic solutions. assuming the perturbation decays polynomially fast as ... | weakly asymptotically quasiperiodic solutions for time-dependent hamiltonians with a view to celestial mechanics |
power plants and large industrial facilities contribute more than half of global anthropogenic co2 emissions. quantifying the emissions of these point sources is therefore one of the main goals of the planned constellation of anthropogenic co2 monitoring satellites (co2m) of the european copernicus program. atmospheric... | evaluation of simulated co2 power plant plumes from six high-resolution atmospheric transport models |
the dynamics and collisions of dust acoustic (da) shock excitations traveling in opposite directions are theoretically investigated in a three-dimensional self-gravitating magnetized electron-depleted dusty plasma whose ingredients are extremely warm positively and negatively charged massive dust grains as well as ions... | dynamics and head-on collisions of multidimensional dust acoustic shock waves in a self-gravitating magnetized electron-depleted dusty plasma |
analysis of the propagation of the comet nucleus sounding experiment by radiowave transmission (consert) signal throughout the small lobe of the 67p/cg nucleus has permitted us to deduce the real part of the permittivity, at a value of 1.27 ± 0.05. the first interpretation of this value, using the dielectric properties... | cosmochemical implications of consert permittivity characterization of 67p/cg |
a rigorous theoretical investigation is made to study the characteristics of dust-acoustic (da) waves (daws) in an electron depleted unmagnetized opposite polarity dusty plasma system that contains super-thermal ( κ-distributed) ions, mobile positively and negatively charged dust grains for the first time. the reductiv... | dust-acoustic rogue waves in an electron depleted plasma |
glycine (gly), the simplest amino-acid building-block of proteins, has been identified on icy dust grains in the interstellar medium, icy comets, and ice covered meteorites. these astrophysical ices contain simple molecules (e.g., co2, h2o, ch4, hcn, and nh3) and are exposed to complex radiation fields, e.g., uv, γ, or... | glycine formation in co2:ch4:nh3 ices induced by 0-70 ev electrons |
context. the rosetta spacecraft provided us with a unique opportunity to study comet 67p/churyumov-gerasimenko (67p) from a close perspective and over a 2-yr time period. comet 67p is a weakly active comet. it was therefore unexpected to find an active and dynamic ionosphere where the cometary ions were largely dominan... | plasma source and loss at comet 67p during the rosetta mission |
the first known interstellar object, 1i/2017 u1 'oumuamua, displayed such unusual properties that its origin remains a subject of much debate. we propose that 'oumuamua's properties could be explained as those of a fractal dust aggregate (a "dust bunny") formed in the inner coma of a fragmenting exo-oort cloud comet. s... | \'oumuamua as a cometary fractal aggregate: the "dust bunny" model |
complex organic molecules (coms) have been observed toward several low-mass young stellar objects (lysos). small and heterogeneous samples have so far precluded conclusions on typical com abundances, as well as the origin(s) of abundance variations between sources. we present observations toward 16 deeply embedded (cla... | complex organic molecules toward embedded low-mass protostars |
the question of what triggered the nongravitational acceleration of 1i/`oumuamua continues to attract researchers' attention. the absence of any signs of activity notwithstanding, the prevailing notion is that the acceleration of the stellar, cigar-like object was prompted by outgassing. however, the spitzer space tele... | outgassing as trigger of 1i/`oumuamua's nongravitational acceleration: could this hypothesis work at all? |
intrinsically faint comets in nearly-parabolic orbits with perihelion distances much smaller than 1 au exhibit strong propensity for suddenly disintegrating at a time not long before perihelion, as shown by bortle (1991). evidence from available observations of such comets suggests that the disintegration event usually... | 1i/`oumuamua as debris of dwarf interstellar comet that disintegrated before perihelion |
aims: we present the spatial and diurnal variation of water outgassing on comet 67p/churyumov-gerasimenko using the ho rotational transition line at 556.936 ghz observed from rosetta/miro in august 2014.methods: the water line was analyzed with a non-lte radiative transfer model and an optimal estimation method to retr... | spatial and diurnal variation of water outgassing on comet 67p/churyumov-gerasimenko observed from rosetta/miro in august 2014 |
most of the gaseous molecules that are detected in cometary atmospheres are produced through sublimation of nucleus ices. distributed sources may also occur, that is, production within the coma, from the solid component of dust particles that are ejected from the nucleus. glycine, the simplest amino acid, was observed ... | distributed glycine in comet 67p/churyumov-gerasimenko |
according to modern concepts bodies of the solar system formed from a single cloud of gas and dust. calculations show that in the protoplanetary nebula where the temperature is lowered to 1600 k - appeared the first type of metal (aluminum and titanium) and metal oxides in the form of dust particles. with further decre... | activity of processes on the visible surface of planets of solar system |
both heliophysics and planetary physics seek to understand the complex nature of the solar wind's interaction with solar system obstacles like earth's magnetosphere, the ionospheres of venus and mars, and comets. studies with this objective are frequently conducted with the help of single or multipoint in situ electrom... | imaging plasma density structures in the soft x-rays generated by solar wind charge exchange with neutrals |
symmetric cell division requires the even partitioning of genetic information and cytoplasmic contents between daughter cells. whereas the mechanisms coordinating the segregation of the genome are well known, the processes that ensure organelle segregation between daughter cells remain less well understood1. here we id... | actin cables and comet tails organize mitochondrial networks in mitosis |
using 3d radiative mhd simulations and lyman-α transit calculations, we investigate the effect of magnetic fields on the observational signatures of atmospheric escape in exoplanets. using the same stellar wind, we vary the planet's dipole field strength (bp) from 0 to 10g. for bp < 3g, the structure of the escaping... | the effects of magnetic fields on observational signatures of atmospheric escape in exoplanets: double tail structures |
extreme debris disks (edds) are rare systems with peculiarly large amounts of warm dust that may stem from recent giant impacts between planetary embryos during the final phases of terrestrial planet growth. here we report on the identification and characterization of six new edds. these disks surround f5-g9 type main-... | a new sample of warm extreme debris disks from the allwise catalog |
we study the dynamics of the interaction between the solar wind ions and a partially ionized atmosphere around a comet, at a distance of 2.88 au from the sun during a period of low nucleus activity. comparing particle data and magnetic field data for a case study, we highlight the prime role of the solar wind electric ... | mass loading at 67p/churyumov-gerasimenko: a case study |
the star β pictoris harbors a young planetary system of about 20 million years old, which is characterized by the presence of a gaseous and dusty debris disk, at least two massive planets and many minor bodies. for more than thirty years, exocomets transiting the star have been detected using spectroscopy, probing the ... | exocomets size distribution in the β pictoris planetary system |
esa's rosetta mission has followed comet 67p/churyumov-gerasimenko from 3.6 au inbound to 3.6 au outbound. many results are largely unexpected, as compared to previous models based on in situ and ground-based observations of jupiter-family comets. the main topics discussed in this review are (1) the importance of the l... | unexpected and significant findings in comet 67p/churyumov-gerasimenko: an interdisciplinary view |
in this study, cypermethrin toxicity was investigated using physiological, biochemical and cytogenetic parameters, and more than one organ and cell type was preferred to determine these effects. in this multifaceted study, the genotoxicity mechanism of cypermethrin was elucidated by molecular docking. in addition, come... | investigation of cypermethrin toxicity in swiss albino mice with physiological, genetic and biochemical approaches |
context. since august 2014, the osiris narrow angle camera (nac) onboard the rosetta spacecraft has acquired high spatial resolution images of the nucleus of comet 67p/churyumov-gerasimenko, down to the decimeter scale. this paper focuses on the imhotep region, located on the largest lobe of the nucleus, near the equat... | geomorphology of the imhotep region on comet 67p/churyumov-gerasimenko from osiris observations |
context. comet formation by gravitational instability requires aggregates that trigger the streaming instability and cluster in pebble-clouds. these aggregates form as mixtures of dust and ice from (sub-)micrometre-sized dust and ice grains via coagulation in the solar nebula. aim. we investigate the growth of aggregat... | local growth of dust- and ice-mixed aggregates as cometary building blocks in the solar nebula |
we present atacama large millimetre/sub-millimetre array (alma) 1.3 and 0.86 mm observations of the nearby (17.34 pc) f9v star q1 eri (hd 10647, hr 506). this system, with age ~1.4 gyr, hosts a ~2 au radial velocity planet and a debris disc with the highest fractional luminosity of the closest 300 fgk type stars. the a... | high-resolution alma and hst images of q1 eri: an asymmetric debris disc with an eccentric jupiter |
cometary dust particles are best preserved remnants of the matter present at the onset of the formation of the solar system. space missions, telescopic observations and laboratory analyses advanced the knowledge on the properties of cometary dust. cometary samples were returned from comet 81p/wild2 by the stardust miss... | chemical and physical properties of cometary dust |
we present observations of sunset jets on comet 67p/churyumov-gerasimenko by rosetta/osiris camera. in late april 2015, when the comet was at a heliocentric distance of ~1.8 au, clusters of dust jets that originated in the ma'at region on the comet's small lobe were identified from multipleimages and were apparently su... | sunset jets observed on comet 67p/churyumov-gerasimenko sustained by subsurface thermal lag |
it has long been observed that the coma of a comet is often green while its tail is not. while the explanation for this must be that the molecules responsible for the green emission, c2, are photodissociated, the mechanism was, until now, unknown. we have observed the photodissociation of c2 in the laboratory for the f... | photodissociation of dicarbon: how nature breaks an unusual multiple bond |
the fixation probability is the probability that a new mutant introduced in a homogeneous population eventually takes over the entire population. the fixation probability is a fundamental quantity of natural selection, and known to depend on the population structure. amplifiers of natural selection are population struc... | amplification on undirected population structures: comets beat stars |
the cometary secondary ion mass analyzer (cosima) on board the rosetta mission has analysed numerous cometary dust particles collected at very low velocities (a few m s-1) in the environment of comet 67p/churyumov-gerasimenko (hereafter 67p). in these particles, carbon and nitrogen are expected mainly to be part of the... | nitrogen-to-carbon atomic ratio measured by cosima in the particles of comet 67p/churyumov-gerasimenko |
we investigate the plausibility of a cometary source of the unusual transits observed in the kic 8462852 light curve. a single comet of similar size to those in our solar system produces a transit depth of the order of 10-3 lasting less than a day which is much smaller and shorter than the largest dip observed (∼ 20% f... | kic 8462852: transit of a large comet family |
we observed the interstellar comet 2i/borisov using the neil gehrels swift observatory's ultraviolet/optical telescope. we obtained images of the oh gas and dust surrounding the nucleus at six epochs spaced before and after perihelion (-2.56 to 2.54 au). water production rates increased steadily before perihelion from ... | water production rates and activity of interstellar comet 2i/borisov |
the immersion grating infrared spectrometer (igrins) is a revolutionary instrument that exploits broad spectral coverage at high-resolution in the near-infrared. igrins employs a silicon immersion grating as the primary disperser, and volume-phase holographic gratings cross-disperse the h and k bands onto teledyne hawa... | 300 nights of science with igrins at mcdonald observatory |
extremely metal-poor (xmp) galaxies are defined to have a gas-phase metallicity smaller than a tenth of the solar value (12+{log}[{{o/h}}]< 7.69). they are uncommon, chemically and possibly dynamically primitive, with physical conditions characteristic of earlier phases of the universe. we search for new xmps in the... | search for extremely metal-poor galaxies in the sloan digital sky survey. (ii). high electron temperature objects |
we present new, ice species-specific new horizons/alice upper gas coma production limits from the 2019 january 1 mu69/arrokoth flyby of gladstone et al. and use them to make predictions about the rarity of majority hypervolatile (co, n2, ch4) ices in kuiper belt objects and oort cloud comets. these predictions have a n... | a predicted dearth of majority hypervolatile ices in oort cloud comets |
our universe is most radiant at terahertz frequencies (0.1-10.0 thz) (ref. 1), providing critical information on the formation of the planets, stars and galaxies, as well as the atmospheric constituents of the planets, their moons, comets and asteroids2-9. the detection of faint fluxes of photons at terahertz frequenci... | room-temperature heterodyne terahertz detection with quantum-level sensitivity |
collisions of ice particles play an important role in the formation of planetesimals and comets. in recent work, we showed that co2 ice behaves like silicates in collisions. the resulting assumption was that it should therefore stick less efficiently than h2o ice. within this paper, a quantification of the latter is pr... | ice grain collisions in comparison: co2, h2o, and their mixtures |
we study kardar-parisi-zhang equation in spatial dimension 3 or larger driven by a gaussian space-time white noise with a small convolution in space. when the noise intensity is small, it is known that the solutions converge to a random limit as the smoothing parameter is turned off. we identify this limit, in the case... | renormalizing the kardar-parisi-zhang equation in d ≥3 in weak disorder |
recently, the rosina mass spectrometer suite on board the european space agency's rosetta spacecraft discovered an abundant amount of molecular oxygen, o2, in the coma of jupiter family comet 67p/churyumov-gerasimenko of o2/h2o = 3.80 ± 0.85%. it could be shown that o2 is indeed a parent species and that the derived ab... | molecular oxygen in oort cloud comet 1p/halley |
we numerically study the dynamical evolution of observed samples of active and inactive centaurs and clones that reach the jupiter-saturn region. our aim is to compare the evolution between active and inactive centaurs, their end states and their transfer to jupiter family comets and halley-type comets. we find that th... | dynamical evolution and end states of active and inactive centaurs |
the occurrence of emerging organic micropollutants (omps) in sewage sludge has been widely reported; nevertheless, their fate during sludge treatment remains unclear. the objective of this work was to study the fate of omps during mesophilic and thermophilic anaerobic digestion (ad), the most common processes used for ... | is anaerobic digestion effective for the removal of organic micropollutants and biological activities from sewage sludge? |
since its discovery in the first half of the 20th century, scientists have puzzled over the origins of titan’s atmosphere. current models suggest that atmospheric n2 on titan may have originated from nh3-bearing ice with n-isotopic ratios similar to those observed in nh2 in cometary comae (14n/15n ∼ 136). in contrast, ... | contributions from accreted organics to titan’s atmosphere: new insights from cometary and chondritic data |
a new interstellar molecule, ch3nco (methyl isocyanate), has been detected using the 12 m telescope of the arizona radio observatory (aro). ch3nco was identified in spectra covering 48 ghz (68-116 ghz) in the 3 mm segment of a broadband survey of sgr b2(n). thirty very favorable rotational lines (ka = 0 and ka = 1 only... | interstellar detection of methyl isocyanate ch3nco in sgr b2(n): a link from molecular clouds to comets |
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