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several sulphur-bearing species have already been observed in different families of comets. however, the knowledge on the minor sulphur species is still limited. the comet's sulphur inventory is closely linked to the pre-solar cloud and holds important clues to the degree of reprocessing of the material in the solar ne... | sulphur-bearing species in the coma of comet 67p/churyumov-gerasimenko |
aims: the osiris camera onboard the rosetta spacecraft has been acquiring images of the comet 67p/churyumov-gerasimenko (67p)'s nucleus at spatial resolutions down to ~0.17 m/px ever since aug. 2014. these images have yielded unprecedented insight into the morphological diversity of the comet's surface. this paper pres... | regional surface morphology of comet 67p/churyumov-gerasimenko from rosetta/osiris images |
the radio science experiment rsi on-board rosetta determined the mass of the nucleus of comet 67p/churyumov-gerasimenko at the start of the prime mission from 2014 august to november (gm = 666.2 ± 0.2 m3 s-2 or 9982 ± 3 × 1012 kg) and shortly before the end of the mission from 2016 july to september (gm = 665.5 ± 0.1 m... | the nucleus of comet 67p/churyumov-gerasimenko - part i: the global view - nucleus mass, mass-loss, porosity, and implications |
the factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. the peculiar bilobed shape of comet 67p/churyumov-gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavat... | two independent and primitive envelopes of the bilobate nucleus of comet 67p |
complex organic molecules (coms) detected in the gas phase are thought to be mostly formed on icy grains, but no unambiguous detection of icy coms larger than ch3oh has been reported so far. exploring this matter in more detail has become possible with the jwst the critical 5-10 $\mu$m range. in the joys+ program, more... | jwst observations of young protostars (joys+): detection of icy complex organic molecules and ions. i. ch$_4$, so$_2$, hcoo$^-$, ocn$^-$, h$_2$co, hcooh, ch$_3$ch$_2$oh, ch$_3$cho, ch$_3$ocho, ch$_3$cooh |
the grain impact analyzer and dust accumulator (giada) instrument on board esa’s rosetta mission is constraining the origin of the dust particles detected within the coma of comet 67 p/churyumov-gerasimenko (67p). the collected particles belong to two families: (i) compact particles (ranging in size from 0.03 to 1 mm),... | density and charge of pristine fluffy particles from comet 67p/churyumov-gerasimenko |
a systematic analysis of the mixing ratios with respect to h2o for eight species (ch3oh, hcn, nh3, h2co, c2h2, c2h6, ch4, and co) measured with high-resolution infrared spectroscopy in thirty comets between 1997 and 2013 is presented. some trends are beginning to emerge when mixing ratios in individual comets are compa... | emerging trends and a comet taxonomy based on the volatile chemistry measured in thirty comets with high-resolution infrared spectroscopy between 1997 and 2013 |
the cosima mass spectrometer on board the rosetta orbiter has collected dust in the near coma of comet 67p/churyumov-gerasimenko since august 11, 2014. the collected dust particles are identified by taking images with a microscope (cosiscope) under grazing incidence illumination before and after exposure of the target ... | typology of dust particles collected by the cosima mass spectrometer in the inner coma of 67p/churyumov gerasimenko |
although water vapour is the main species observed in the coma of comet 67p/churyumov-gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. the absence of large regions of exposed water ice seems a common fi... | exposed water ice on the nucleus of comet 67p/churyumov-gerasimenko |
in 2016, unambiguous evidence for the presence of the amino acid glycine, an important prebiotic molecule, was deduced based on in situ mass-spectral studies of the coma surrounding cometary ice. this finding is significant because comets are thought to have preserved the icy grains originally found in the interstellar... | extraterrestrial prebiotic molecules: photochemistry vs. radiation chemistry of interstellar ices |
we summarize the collective knowledge of physical and surface properties of comet nuclei, focusing on those that are obtained from remote observations. we now have measurements or constraints on effective radius for over 200 comets, rotation periods for over 60, axial ratios and color indices for over 50, geometric alb... | physical and surface properties of comet nuclei from remote observations |
debris belts on the periphery of planetary systems, encompassing the region occupied by planetary orbits, are massive analogues of the solar system's kuiper belt. they are detected by thermal emission of dust released in collisions amongst directly unobservable larger bodies that carry most of the debris disc mass. we ... | solution to the debris disc mass problem: planetesimals are born small? |
the presence of solid carbonaceous matter in cometary dust was established by the detection of elements such as carbon, hydrogen, oxygen and nitrogen in particles from comet 1p/halley. such matter is generally thought to have originated in the interstellar medium, but it might have formed in the solar nebula—the cloud ... | high-molecular-weight organic matter in the particles of comet 67p/churyumov-gerasimenko |
the detection of interstellar objects passing through the solar system offers the promise of constraining the physical and chemical processes involved in planetary formation in other extrasolar systems. while the effect of outgassing by 1i/2017 u1 (’oumuamua) was dynamically observed, no direct detection of the ejected... | detection of cn gas in interstellar object 2i/borisov |
the m dwarf gj 436 hosts a transiting warm neptune known to experience atmospheric escape. previous observations revealed the presence of a giant hydrogen exosphere transiting the star for more than 5 h, and absorbing up to 56% of the flux in the blue wing of the stellar lyman-α line of neutral hydrogen (h i lyα). the ... | the long egress of gj 436b's giant exosphere |
this chapter reviews the estimates of the dust-to-gas and refractory-to-ice mass ratios derived from rosetta measurements in the lost materials and the nucleus of 67p/churyumov-gerasimenko, respectively. first, the measurements by rosetta instruments are described, as well as relevant characteristics of 67p. the comple... | dust-to-gas and refractory-to-ice mass ratios of comet 67p/churyumov-gerasimenko from rosetta observations |
comets are composed of dust and frozen gases. the ices are mixed with the refractory material either as an icy conglomerate, or as an aggregate of pre-solar grains (grains that existed prior to the formation of the solar system), mantled by an ice layer. the presence of water-ice grains in periodic comets is now well e... | comet 67p/churyumov-gerasimenko sheds dust coat accumulated over the past four years |
we present the discovery of a transiting exoplanet candidate in the k2 field-1 with an orbital period of 9.1457 hr: k2-22b. the highly variable transit depths, ranging from ∼0% to 1.3%, are suggestive of a planet that is disintegrating via the emission of dusty effluents. we characterize the host star as an m-dwarf wit... | the k2-esprint project i: discovery of the disintegrating rocky planet k2-22b with a cometary head and leading tail |
the chemical composition of cometary ices provides clues for the conditions of formation and evolution of the early solar system. a large number of molecules have been identified in cometary atmospheres, from both ground-based observations and space, including in situ investigations. this includes large organic molecul... | the composition of cometary ices |
the nonlinear propagation of heavy-ion-acoustic (hia) waves (hiaws) in a four-component multi-ion plasma (containing inertial heavy negative ions and light positive ions, as well as inertialess nonextensive electrons and positrons) has been theoretically investigated. the nonlinear schrödinger (nls) equation is derived... | heavy ion-acoustic rogue waves in electron-positron multi-ion plasmas |
the origin of the interstellar object 1i/`oumuamua has defied explanation. in a companion paper (jackson & desch, 2021), we show that a body of n2 ice with axes 45 m × 44 m × 7.5 m at the time of observation would be consistent with its albedo, nongravitational acceleration, and lack of observed co or co2 or dust. ... | 1i/`oumuamua as an n2 ice fragment of an exo pluto surface ii: generation of n2 ice fragments and the origin of `oumuamua |
the philae lander, part of the rosetta mission to investigate comet 67p/churyumov-gerasimenko, was delivered to the cometary surface in november 2014. here we report the precise circumstances of the multiple landings of philae, including the bouncing trajectory and rebound parameters, based on engineering data in conju... | the landing(s) of philae and inferences about comet surface mechanical properties |
during its 2 yr mission around comet 67p/churyumov-gerasimenko, esa's rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. many studies have presented the typical features associated with the activity of the nucleus, such as localized dust and gas jets. here, we ... | summer fireworks on comet 67p |
this review presents our understanding of cometary dust at the end of 2017. for decades, insight about the dust ejected by nuclei of comets had stemmed from remote observations from earth or earth's orbit, and from flybys, including the samples of dust returned to earth for laboratory studies by the stardust return cap... | cometary dust |
we use the c/n ratio as a monitor of the delivery of key ingredients of life to nascent terrestrial worlds. total elemental c and n contents, and their ratio, are examined for the interstellar medium, comets, chondritic meteorites and terrestrial planets; we include an updated estimate for the bulk silicate earth (c/n ... | tracing the ingredients for a habitable earth from interstellar space through planet formation |
the philae lander provides a unique opportunity to investigate the internal structure of a comet nucleus, providing information about its formation and evolution in the early solar system. we present comet nucleus sounding experiment by radiowave transmission (consert) measurements of the interior of comet 67p/churyumo... | properties of the 67p/churyumov-gerasimenko interior revealed by consert radar |
the physical properties of cometary nuclei observed today relate to their complex history and help to constrain their formation and evolution. in this article, we review some of the main physical properties of cometary nuclei and focus in particular on the thermal, mechanical, structural and dielectric properties, emph... | the thermal, mechanical, structural, and dielectric properties of cometary nuclei after rosetta |
we design and implement a scalable hard particle monte carlo simulation toolkit (hpmc), and release it open source as part of hoomd-blue. hpmc runs in parallel on many cpus and many gpus using domain decomposition. we employ bvh trees instead of cell lists on the cpu for fast performance, especially with large particle... | scalable metropolis monte carlo for simulation of hard shapes |
in this study, heavy metal pollution in the pazarsuyu stream of giresun province and the protective role of lycopene against the toxicity caused by this pollution were investigated using the allium test. germination percentage, root length and weight gain as physiological markers of toxicity; mitotic index (mi), micron... | comprehensive toxicity screening of pazarsuyu stream water containing heavy metals and protective role of lycopene |
we reconstruct the temporal evolution of the source distribution for the four major gas species h2o, co2, co, and o2 on the surface of comet 67p/churyumov-gerasimenko during its 2015 apparition. the analysis applies an inverse coma model and fits to data between 2014 august 6 and 2016 september 5 measured with the doub... | surface localization of gas sources on comet 67p/churyumov-gerasimenko based on dfms/cops data |
the d/h ratio in cometary water has been shown to vary between 1 and 3 times the earth's oceans value, in both oort cloud comets and jupiter-family comets originating from the kuiper belt. this has been taken as evidence that comets contributed a relatively small fraction of the terrestrial water. we present new sensit... | terrestrial deuterium-to-hydrogen ratio in water in hyperactive comets |
context. the properties of the smallest subunits of cometary dust contain information on their origin and clues to the formation of planetesimals and planets. compared to interplanetary dust particles or particles collected during the stardust mission, dust collected in the coma of comet 67p/churyumov-gerasimenko (67p)... | dust of comet 67p/churyumov-gerasimenko collected by rosetta/midas: classification and extension to the nanometer scale |
in this chapter we review our knowledge of our galaxy's cometary population outside our oort cloud - exocomets and interstellar objects (isos). we start with a brief overview of planetary system formation, viewed as a general process around stars. we then take a more detailed look at the creation and structure of exoco... | interstellar objects and exocomets |
we present the first study of the three-dimensional (3d) dynamics of the gas in the entire southern orion cloud complex. we used the parallaxes and proper motions of young stellar objects (ysos) from gaia dr2 as a proxy for gas distance and proper motion, and the gas radial velocities from archival co data, to compute ... | 3d dynamics of the orion cloud complex. discovery of coherent radial gas motions at the 100-pc scale |
quantifying the composition of the material in protoplanetary disks is essential to determining the potential for exoplanetary systems to produce and support habitable environments. when considering potential habitability, complex organic molecules are relevant, key among which is methanol (ch3oh). methanol primarily f... | an inherited complex organic molecule reservoir in a warm planet-hosting disk |
the kuiper belt of our solar system is a source of short-period comets that may have delivered water and other volatiles to earth and the other terrestrial planets. however, the distribution of water and other volatiles in extrasolar planetary systems is largely unknown. we report the discovery of an accretion of a kui... | the chemical composition of an extrasolar kuiper-belt-object |
we report on magnetic field measurements made in the innermost coma of 67p/churyumov-gerasimenko in its low-activity state. quasi-coherent, large-amplitude (δ b/b ~ 1), compressional magnetic field oscillations at ~ 40 mhz dominate the immediate plasma environment of the nucleus. this differs from previously studied co... | observation of a new type of low-frequency waves at comet 67p/churyumov-gerasimenko |
large language models (llms) present strong general capabilities, and a current compelling challenge is stimulating their specialized capabilities, such as machine translation, through low-cost instruction tuning. the standard instruction-following data is sequentially organized as the concatenation of an instruction, ... | improving translation faithfulness of large language models via augmenting instructions |
it has recently been shown by egal et al. that some types of existing meteor in-atmosphere trajectory estimation methods may be less accurate than others, particularly when applied to high-precision optical measurements. the comparative performance of trajectory solution methods has previously only been examined for a ... | estimating trajectories of meteors: an observational monte carlo approach - i. theory |
recent atacama large millimeter/submillimeter array observations present mounting evidence for the presence of exocometary gas released within kuiper belt analogs around nearby main-sequence stars. this represents a unique opportunity to study their ice reservoir at the younger ages when volatile delivery to planets is... | detection of exocometary co within the 440 myr old fomalhaut belt: a similar co+co2 ice abundance in exocomets and solar system comets |
the chemical composition of planets is inherited from that of the natal protoplanetary disk at the time of planet formation. increasing observational evidence suggests that planet formation occurs in less than 1-2 myr. this motivates the need for spatially resolved spectral observations of young class i disks, as carri... | alma chemical survey of disk-outflow sources in taurus (alma-dot). ii. vertical stratification of co, cs, cn, h2co, and ch3oh in a class i disk |
we present the first census of the interstellar complex organic molecules (icoms) in the low-mass class i protostar svs13-a, obtained by analysing data from the iram-30 m large project asai (astrochemical surveys at iram). they consist of a high-sensitivity unbiased spectral survey at the 1mm, 2mm, and 3mm iram bands. ... | the census of interstellar complex organic molecules in the class i hot corino of svs13-a |
we discuss observations of the journey throughout the solar system of a large interplanetary coronal mass ejection (icme) that was ejected at the sun on 14 october 2014. the icme hit mars on 17 october, as observed by the mars express, mars atmosphere and volatile evolution mission (maven), mars odyssey, and mars scien... | interplanetary coronal mass ejection observed at stereo-a, mars, comet 67p/churyumov-gerasimenko, saturn, and new horizons en route to pluto: comparison of its forbush decreases at 1.4, 3.1, and 9.9 au |
context. close-in exoplanets interact with their host stars gravitationally as well as via their magnetized plasma outflows. the rich dynamics that arises may result in distinct observable features.aims: our objective is to study and classify the morphology of the different types of interaction that can take place betw... | classification of magnetized star-planet interactions: bow shocks, tails, and inspiraling flows |
if a component of the dark matter has dissipative interactions, it could collapse to form a thin dark disk in our galaxy that is coplanar with the baryonic disk. it has been suggested that dark disks could explain a variety of observed phenomena, including periodic comet impacts. using the first data release from the g... | constraining a thin dark matter disk with g a i a |
we report the clear detection of c$_2$ and of abundant nh$_2$ in the first prominently active interstellar comet, 2i/borisov. we observed 2i on three nights in november 2019 at optical wavelengths 4800--9300 åwith the multi-unit spectroscopic explorer (muse) integral-field spectrograph on the eso/very large telescope. ... | interstellar comet 2i/borisov as seen by muse: c$_2$, nh$_2$ and red cn detections |
comet c/2016 r2 (panstarrs) has a peculiar volatile composition, with co being the dominant volatile, as opposed to h2o, and one of the largest n2/co ratios ever observed in a comet. using observations obtained with the spitzer space telescope, nasa’s infrared telescope facility, the 3.5 m astrophysical research consor... | the peculiar volatile composition of co-dominated comet c/2016 r2 (panstarrs) |
isotopic ratios in comets provide keys for the understanding of the origin of cometary material, and the physical and chemical conditions in the early solar nebula. we review here measurements acquired on the d/h, 14n/15n, 16o/18o, 12c/13c, and 32s/34s ratios in cometary grains and gases, and discuss their cosmogonic i... | cometary isotopic measurements |
ls i +61° 303 is one of the rare gamma-ray binaries1 that emit most of their luminosity in photons with energies beyond 100 mev (ref. 2). it is well characterized—the ~26.5 day orbital period is clearly detected at many wavelengths2-4—and other aspects of its multifrequency behaviour make it the most interesting exampl... | radio pulsations from a neutron star within the gamma-ray binary ls i +61° 303 |
experiments were conducted to investigate the health of fish channa punctatus inhabiting heavy metal-loaded waste water. heavy metals in the order of fe > mn > zn > co > ni > cu = cr were present in the waste water. gills had high metal load followed by liver and then kidney. albumin, albumin to globulin... | multiple biomarker responses (serum biochemistry, oxidative stress, genotoxicity and histopathology) in channa punctatus exposed to heavy metal loaded waste water |
the coma of comet 67p/churyumov-gerasimenko has been probed by the rosetta spacecraft and shows a variety of different molecules. the rosina comet pressure sensor and the double focusing mass spectrometer provide in situ densities for many volatile compounds including the 14 gas species h2o, co2, co, h2s, o2, c2h6, ch3... | the gas production of 14 species from comet 67p/churyumov-gerasimenko based on dfms/cops data from 2014 to 2016 |
understanding the effects of high-energy radiation and stellar winds on planetary atmospheres is vital for explaining the observed properties of close-in exoplanets. observations of transiting exoplanets in the triplet of metastable helium lines at 10830 å allow extended atmospheres and escape processes to be studied f... | the posttransit tail of wasp-107b observed at 10830 å |
images of comet 67p/churyumov-gerasimenko acquired by the osiris (optical, spectroscopic and infrared remote imaging system) imaging system onboard the european space agency’s rosetta spacecraft at scales of better than 0.8 meter per pixel show a wide variety of different structures and textures. the data show the impo... | the morphological diversity of comet 67p/churyumov-gerasimenko |
the evolutionary past of our solar system can be pieced together by comparing analogous low-mass protostars with remnants of our protosolar nebula - comets. sulphur-bearing molecules may be unique tracers of the joint evolution of the volatile and refractory components. alma band 7 data from the large unbiased protoste... | the alma-pils survey: the sulphur connection between protostars and comets: iras 16293-2422 b and 67p/churyumov-gerasimenko |
the properties of dust in the protoplanetary disc are key to understanding the formation of planets in our solar system. many models of dust growth predict the development of fractal structures which evolve into non-fractal, porous dust pebbles representing the main component for planetesimal accretion. in order to und... | fractal cometary dust - a window into the early solar system |
we present high-resolution imaging observations of interstellar comet 2i/borisov (formerly c/2019 q4) obtained using the hubble space telescope. scattering from the comet is dominated by a coma of large particles (characteristic size ∼0.1 mm) ejected anisotropically. convolution modeling of the coma surface brightness ... | the nucleus of interstellar comet 2i/borisov |
to understand how phosphorus (p)-bearing molecules are formed in star-forming regions, we have analysed the atacama large millimeter/submillimeter array (alma) observations of pn and po towards the massive star-forming region afgl 5142, combined with a new analysis of the data of the comet 67p/churyumov-gerasimenko tak... | alma and rosina detections of phosphorus-bearing molecules: the interstellar thread between star-forming regions and comets |
the rosetta spacecraft has investigated comet 67p/churyumov-gerasimenko from large heliocentric distances to its perihelion passage and beyond. we trace the seasonal and diurnal evolution of the colors of the 67p nucleus, finding changes driven by sublimation and recondensation of water ice. the whole nucleus became re... | rosetta’s comet 67p/churyumov-gerasimenko sheds its dusty mantle to reveal its icy nature |
context. dust jets (i.e., fuzzy collimated streams of cometary material arising from the nucleus) have been observed in situ on all comets since the giotto mission flew by comet 1p/halley in 1986, and yet their formation mechanism remains unknown. several solutions have been proposed involving either specific propertie... | are fractured cliffs the source of cometary dust jets? insights from osiris/rosetta at 67p/churyumov-gerasimenko |
we develop an evolutionary model of the long-period comet (lpc) population, starting from their birthplace in a massive trans-neptunian disk that was dispersed by migrating giant planets. most comets that remain bound to the solar system are stored in the oort cloud. galactic tides and passing stars make some of these ... | origin and evolution of long-period comets |
aims: we study the link between gravitational slopes and the surface morphology on the nucleus of comet 67p/churyumov-gerasimenko and provide constraints on the mechanical properties of the cometary material (tensile, shear, and compressive strengths).methods: we computed the gravitational slopes for five regions on th... | gravitational slopes, geomorphology, and material strengths of the nucleus of comet 67p/churyumov-gerasimenko from osiris observations |
we present an improved model for interplanetary dust grain fluxes in the outer solar system constrained by in situ dust density observations. a dynamical dust grain tracing code is used to establish relative dust grain densities and three-dimensional velocity distributions in the outer solar system for four main source... | an improved model for interplanetary dust fluxes in the outer solar system |
at present, there exists no consensus in the astronomical community regarding either the bulk composition or the formation mechanism for the interstellar object 1i/2017 u1 ('oumuamua). with the goal of assessing the merits of the various scenarios that have been suggested to explain 'oumuamua's appearance and observed ... | constraints on the occurrence of 'oumuamua-like objects |
outbursts occur commonly on comets1 with different frequencies and scales2,3. despite multiple observations suggesting various triggering processes4,5, the driving mechanism of such outbursts is still poorly understood. landslides have been invoked6 to explain some outbursts on comet 103p/hartley 2, although the proces... | the pristine interior of comet 67p revealed by the combined aswan outburst and cliff collapse |
cometary studies suggest that the organic composition of the early solar nebula was rich in complex nitrile species such ch3cn. recent alma detections in protoplanetary disks suggest that these species may be common during planet and comet formation, but connecting gas-phase measurements to cometary abundances first re... | the distribution and excitation of ch3cn in a solar nebula analog |
context. the detection of complex organic molecules related with prebiotic chemistry in star-forming regions allows us to investigate how the basic building blocks of life are formed.aims: ethylene glycol (ch2oh)2 is the simplest sugar alcohol and the reduced alcohol of the simplest sugar glycoladehyde (ch2ohcho). we s... | formation of ethylene glycol and other complex organic molecules in star-forming regions |
comets contain the best-preserved material from the beginning of our planetary system. their nuclei and comae composition reveal clues about physical and chemical conditions during the early solar system when comets formed. rosina (rosetta orbiter spectrometer for ion and neutral analysis) onboard the rosetta spacecraf... | time variability and heterogeneity in the coma of 67p/churyumov-gerasimenko |
aims: the discovery of the first active interstellar object 2i/borisov provides an unprecedented opportunity to study planetary formation processes in another planetary system. in particular, spectroscopic observations of 2i allow us to constrain the composition of its nuclear ices.methods: we obtained optical spectra ... | 2i/borisov: a c2-depleted interstellar comet |
the presence of numerous complex organic molecules (coms; defined as those containing six or more atoms) around protostars shows that star formation is accompanied by an increase of molecular complexity. these coms may be part of the material from which planetesimals and, ultimately, planets formed. comets represent so... | ethyl alcohol and sugar in comet c/2014 q2 (lovejoy) |
when comets approach the sun, their surface is heated and the volatile species start to sublimate. due to the increasing gas pressure, dust is ejected off the surface, which can be observed as cometary coma, dust tail, and trail. however, the underlying physical processes are not fully understood. using state-of-the-ar... | on the activity of comets: understanding the gas and dust emission from comet 67/churyumov-gerasimenko's south-pole region during perihelion |
solar system formation models predict that the building blocks of planetesimals were mm- to cm-sized pebbles, aggregates of ices and non-volatile materials, consistent with the compact particles ejected by comet 67p/churyumov-gerasimenko (67p hereafter) and detected by giada (grain impact analyzer and dust accumulator)... | comet 67p/churyumov-gerasimenko preserved the pebbles that formed planetesimals |
during the formation of our solar system, a large number of planetesimals were ejected into interstellar space by gravitational encounters with the planets. debris disks observations and numerical simulations indicate that many other planetary systems, now known to be quite common, would have undergone a similar dynami... | interstellar planetesimals |
atmospheric escape from close-in exoplanets is thought to be crucial in shaping observed planetary populations. recently, significant progress has been made in observing this process in action through excess absorption in-transit spectra and narrowband light curves. we model the escape of initially homogeneous planetar... | stellar wind confinement of evaporating exoplanet atmospheres and its signatures in 1083 nm observations |
results are presented from a video-based meteoroid orbit survey conducted in new zealand between sept. 2014 and dec. 2016, which netted 24,906 orbits from +5 to -5 magnitude meteors. 44 new southern hemisphere meteor showers are identified after combining this data with that of other video-based networks. results are c... | a survey of southern hemisphere meteor showers |
we describe here updates and new elements of the catalogue of cometary orbits and their dynamical evolution (code) that, in its original 2020 version, has been introduced by królikowska & dybczyński (2020). currently, the code catalogue offers rich sets of orbital solutions for almost a complete sample of oort spik... | news in the code catalogue |
james webb space telescope's nirspec infrared imaging spectrometer observed the outer solar system dwarf planets eris and makemake in reflected sunlight at wavelengths spanning 1 through 5 microns. both objects have high albedo surfaces that are rich in methane ice, with a texture that permits long optical path lengths... | measurement of d/h and 13c/12c ratios in methane ice on eris and makemake: evidence for internal activity |
we study non-hermitian higher-order weyl semimetals (nhhowsms) possessing real spectra and having inversion i (i -nhhowsm) or time-reversal symmetry t (t -nhhowsm). when the reality of bulk spectra is lost, the nhhowsms exhibit various configurations of surface fermi arcs and exceptional fermi rings (efrs), providing a... | non-hermitian higher-order weyl semimetals |
ice naturally forms in the disordered or ``amorphous'' state when accreted from vapor at temperatures and pressures found in the interstellar medium and in the frigid, low density outer regions of the sun's protoplanetary disk. it is therefore the expected form of ice in comets and other primitive bodies that have esca... | amorphous ice in comets: evidence and consequences |
the primordial disc of small icy planetesimals, once located at 15-$30\, \mathrm{au}$ from the sun, was disrupted by giant planet migration in the early solar system. the primordial disc thereby became the source region of objects in the present-day kuiper belt, scattered disc, and oort cloud. i present the thermophysi... | thermophysical evolution of planetesimals in the primordial disc |
the recently discovered population of interstellar objects presents us with the opportunity to characterize material from extrasolar planetary and stellar systems up close. the forthcoming vera c. rubin observatory legacy survey of space and time (lsst) will provide an unprecedented increase in sensitivity to these obj... | the population of interstellar objects detectable with the lsst and accessible for in situ rendezvous with various mission designs |
it has recently been suggested that a gravitational transition of the effective newton's constant geff by about 10%, 50–150 myrs ago could lead to the resolution of both the hubble crisis and the growth tension of the standard λcdm model. hints for such an abrupt transition with weaker gravity at times before the trans... | is the hubble crisis connected with the extinction of dinosaurs? |
induced magnetospheres form around conductive non-magnetized planetary objects (such as the ionospheres of mars, venus, titan, pluto and comets) in the electrodynamic interaction with a magnetized flowing plasma, such as the solar wind. the resulting induced currents couple the ionosphere and the deflected plasma, thus... | the global current systems of the martian induced magnetosphere |
we analyse the rosetta orbiter spectrometer for ion and neutral analysis (rosina) - the double focusing mass spectrometer data between 2014 august and 2016 february to examine the effect of seasonal variations on the four major species within the coma of 67p/churyumov-gerasimenko (h2o, co2, co, and o2), resulting from ... | direct simulation monte carlo modelling of the major species in the coma of comet 67p/churyumov-gerasimenko |
context. the rosetta magnetometer rpc-mag has been exploring the plasma environment of comet 67p/churyumov-gerasimenko since august 2014. the first months were dominated by low-frequency waves which evolved into more complex features. however, at the end of july 2015, close to perihelion, the magnetometer detected a re... | first detection of a diamagnetic cavity at comet 67p/churyumov-gerasimenko |
we develop an activity model based on ice sublimation and gas diffusion inside cm-sized pebbles making-up a cometary nucleus. our model explains cometary activity assuming no free parameters and fixing the nucleus surface temperature ts, its gradient below the nucleus surface at thermal equilibrium, the pressure inside... | how comets work: nucleus erosion versus dehydration |
jupiter-family comets (jfcs) are the evolutionary products of trans-neptunian objects (tnos) that evolve through the giant planet region as centaurs and into the inner solar system. through numerical orbital evolution calculations following a large number of tno test particles that enter the centaur population, we have... | 29p/schwassmann-wachmann 1, a centaur in the gateway to the jupiter-family comets |
as the sun moves through the surrounding partially ionized medium, neutral hydrogen atoms penetrate the heliosphere, and through charge exchange with the supersonic solar wind, create a population of hot pick-up ions (puis). until recently, the consensus was that the shape of the heliosphere is comet-like. the terminat... | a small and round heliosphere suggested by magnetohydrodynamic modelling of pick-up ions |
comets evolve due to sublimation of ices embedded inside porous dust, triggering dust emission (that is, erosion) followed by mass loss, mass redistribution and surface modifications. surface changes were revealed by the deep impact and stardust next missions for comet 9p/tempel 1 (ref. 1), and a full inventory of the ... | macro and micro structures of pebble-made cometary nuclei reconciled by seasonal evolution |
aims: we derive for the first time the size-frequency distribution of boulders on a comet, 67p/churyumov-gerasimenko (67p), computed from the images taken by the rosetta/osiris imaging system. we highlight the possible physical processes that lead to these boulder size distributions.methods: we used images acquired by ... | size-frequency distribution of boulders ≥7 m on comet 67p/churyumov-gerasimenko |
organohalogens, a class of molecules that contain at least one halogen atom bonded to carbon, are abundant on the earth where they are mainly produced through industrial and biological processes1. consequently, they have been proposed as biomarkers in the search for life on exoplanets2. simple halogen hydrides have bee... | protostellar and cometary detections of organohalogens |
primitive objects like comets hold important information on the material that formed our solar system. several comets have been visited by spacecraft and many more have been observed through earth- and space-based telescopes. still our understanding remains limited. molecular abundances in comets have been shown to be ... | on the origin and evolution of the material in 67p/churyumov-gerasimenko |
on 12 november 2014, the philae lander descended towards comet 67p/churyumov-gerasimenko, bounced twice off the surface, then arrived under an overhanging cliff in the abydos region. the landing process provided insights into the properties of a cometary nucleus1-3. here we report an investigation of the previously und... | the philae lander reveals low-strength primitive ice inside cometary boulders |
the rosetta mission provides an unprecedented possibility to study the interaction of comets with the solar wind. as the spacecraft accompanies comet 67p/churyumov-gerasimenko from its very low-activity stage through its perihelion phase, the physics of mass loading is witnessed for various activity levels of the nucle... | interaction of the solar wind with comets: a rosetta perspective |
recent alma observations unveiled the structure of co gas in the 23 myr old β pictoris planetary system, a component that has been discovered in many similarly young debris discs. we here present alma co j = 2-1 observations, at an improved spectro-spatial resolution and sensitivity compared to previous co j = 3-2 obse... | exocometary gas structure, origin and physical properties around β pictoris through alma co multitransition observations |
we review the complex relationship between the dust-to-gas mass ratio usually estimated in the material lost by comets, and the refractory-to-ice mass ratio inside the nucleus, which constrains the origin of comets. such a relationship is dominated by the mass transfer from the perihelion erosion to fallout over most o... | the refractory-to-ice mass ratio in comets |
comet 67p/churyumov-gerasimenko (67p hereinafter) is characterized by a dust transfer from the southern hemi-nucleus to the night-side northern dust deposits, which constrains the dust-to-ices mass ratio inside the nucleus to values a factor of 2 larger than that provided by the lost mass of gas and non-volatiles. this... | the dust-to-ices ratio in comets and kuiper belt objects |
several comets observed at close range have bilobate shapes1, including comet 67p/churyumov-gerasimenko (67p/c-g), which was imaged by the european space agency's rosetta mission2,3. bilobate comets are thought to be primordial because they are rich in supervolatiles (for example, n2 and co) and have a low bulk density... | catastrophic disruptions as the origin of bilobate comets |
methyl isocyanate (ch3nco) belongs to a select group of interstellar molecules considered to be relevant precursors in the formation of larger organic compounds, including those with peptide bonds. the molecule has only been detected in a couple of high-mass protostars and potentially on comets. a formation route on ic... | the alma-pils survey: detection of ch3nco towards the low-mass protostar iras 16293-2422 and laboratory constraints on its formation |
context. since its rendezvous with comet 67p/churyumov-gerasimenko (67p), the rosetta spacecraft has provided invaluable information contributing to our understanding of the cometary environment. on board, the virtis and rosina instruments can both measure gas parameters in the rarefied cometary atmosphere, the so-call... | three-dimensional direct simulation monte-carlo modeling of the coma of comet 67p/churyumov-gerasimenko observed by the virtis and rosina instruments on board rosetta |
since osiris started acquiring high-resolution observations of the surface of the nucleus of comet 67p/churyumov-gerasimenko, over one hundred meter-sized bright spots have been identified in numerous types of geomorphologic regions, but mostly located in areas receiving low insolation. the bright spots are either clus... | osiris observations of meter-sized exposures of h2o ice at the surface of 67p/churyumov-gerasimenko and interpretation using laboratory experiments |
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