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lunar regolith breccias are temporal archives of magmatic and impact bombardment processes on the moon. apollo 16 sample 60016 is an "ancient" feldspathic regolith breccia that was converted from a soil to a rock at ~3.8 ga. the breccia contains a small (70 × 50 μm) rock fragment composed dominantly of an fe-oxide phas... | identification of magnetite in lunar regolith breccia 60016: evidence for oxidized conditions at the lunar surface |
context. centaurs are icy objects in transition between the trans-neptunian region and the inner solar system, orbiting the sun in the giant planet region. some centaurs display cometary activity, which cannot be sustained by the sublimation of water ice in this part of the solar system, and has been hypothesized to be... | ossos. xi. no active centaurs in the outer solar system origins survey |
by conserving momentum during the mixing of fast solar wind flow and slow planetary ion flow in an inelastic way, mass loading converts kinetic energy to other forms - e.g. first to electrical energy through charge separation and then to thermal energy (randomness) through gyromotion of the newly born cold ions for the... | energy conversion through mass loading of escaping ionospheric ions for different kp values |
it is a well-known fact that the presence of a massive perturber interacting with a population of minor bodies following very eccentric orbits can strongly affect the distribution of their nodal distances. the details of this process have been explored numerically and its outcome confirmed observationally in the case o... | evidence for a possible bimodal distribution of the nodal distances of the extreme trans-neptunian objects: avoiding a trans-plutonian planet or just plain bias? |
among the near-earth object (neo) population, there are comets and active asteroids which are sources of fragments that initially move together; in addition, some neos follow orbits temporarily trapped in a web of secular resonances. these facts contribute to increasing the risk of meteoroid strikes on earth, making it... | far from random: dynamical groupings among the neo population |
a sequence of events, dominated by two outbursts and ending with the preperihelion disintegration of comet c/2017 s3, is examined. the onset times of the outbursts are determined with high accuracy from the light curve of the nuclear condensation before it disappeared following the second outburst. while the brightness... | preperihelion outbursts and disintegration of comet c/2017 s3 (pan-starrs) |
given rapid photodissociation and photodegradation, the recently discovered organics in the martian subsurface and atmosphere were probably delivered in geologically recent times. possible parent bodies are c-type asteroids, comets, and interplanetary dust particles (idps). the dust infall rate was estimated, using dif... | delivery of organics to mars through asteroid and comet impacts |
the corsair (comet rendezvous, sample acquisition, investigation, and return) mission was a proposal for the nasa new frontiers program. it belongs to the comet surface sample return mission theme which focuses on acquiring and returning to earth a macroscopic sample from the surface of a comet nucleus. corsair uses a ... | development and testing of a pyro-driven launcher for harpoon-based comet sample acquisition |
deep impact, epoxi and rosetta missions visited comets 9p/tempel 1, 103p/hartley 2 and 67p/churyumov-gerasimenko, respectively. each of these three missions was equipped with both multispectral imagers and infrared spectrometers. bright blue features containing water ice were detected in each of these comet nuclei. we ... | comparative study of water ice exposures on cometary nuclei using multispectral imaging data |
breast cancer is a major complication in women and numerous approaches are being developed to overcome this problem. in conventional treatments such as chemotherapy and radiotherapy the post side effects cause an unsuitable effect in treatment of cancer. hence, it is essential to develop a novel strategy for the treatm... | anti-proliferative effect of biogenic gold nanoparticles against breast cancer cell lines (mda-mb-231 & mcf-7) |
iras 17256-3631 is a southern galactic massive star-forming region located at a distance of 2 kpc. in this paper, we present a multiwavelength investigation of the embedded cluster, the h ii region, as well as the parent cloud. radio images at 325, 610 and 1372 mhz were obtained using giant metrewave radio telescope, i... | star formation towards the southern cometary h ii region iras 17256-3631 |
the eruption of mount tambora in indonesia in 1815 was one of the most powerful of its kind in recorded history. this contribution addresses climatic responses to it, the post-eruption weather, and its impacts on human life in the czech lands. the climatic effects are evaluated in terms of air temperature and precipita... | climatic effects and impacts of the 1815 eruption of mount tambora in the czech lands |
the rolis, civa-p and osiris instruments on-board the philae lander and the rosetta orbiter acquired high-resolution images during the lander's descent towards the targeted landing site agilkia, during its unexpected rebounds and at the final landing site abydos on comet 67p/churyumov-gerasimenko. we, exploited these i... | philae locating and science support by robotic vision techniques |
the rosetta observations have greatly advanced our knowledge of the cometary nucleus and its immediate environment. however, constraints on the mission (both planned and unplanned), the only partially successful philae lander, and other instrumental issues have inevitably resulted in open questions. surprising results ... | towards new comet missions |
we report here time-domain infrared spectroscopy and optical photometry of the hd 145263 silica-rich circumstellar-disk system taken from 2003 through 2014. we find an f4v host star surrounded by a stable, massive 1022-1023 kg (mmoon to mmars) dust disk. no disk gas was detected, and the primary star was seen rotating ... | hd 145263: spectral observations of silica debris disk formation via extreme space weathering? |
on 2019 august 7, an impact flash lasting ∼1 s was observed on jupiter. the video of this event was analysed to obtain the light curve, and determine the energy release and initial mass. we find that the impactor released a total energy of 96-151 kilotons of tnt, corresponding to an initial mass between 190 and 260 met... | fragmentation modelling of the 2019 august impact on jupiter |
remote investigations of ancient matter in the solar system have traditionally been carried out through observations of long-period (lp) comets, which are less affected by solar irradiation than their short-period counterparts orbiting much closer to the sun. here we summarize the results of our decade-long survey of t... | activity of 50 long-period comets beyond 5.2 au |
the exceptionally favorable close approach of jupiter-family comet 46p/wirtanen in 2018 december enabled characterization of its primary volatile composition with exceptionally high spatial resolution and sensitivities using the ishell spectrograph at the nasa infrared telescope facility on maunakea, h. we sampled emis... | testing short-term variability and sampling of primary volatiles in comet 46p/wirtanen |
six asteroids including two neas, one of which is pha, accessible for observation in september 2012 were investigated using a low-resolution (r ≈ 100) spectrophotometry in the range 0.35-0.90 μm with the aim to study features of their reflectance spectra. a high-altitude position of our terskol observatory (3150 m abov... | spectrophotometry of (32) pomona, (145) adeona, (704) interamnia, (779) nina, (330825) 2008 xe3, and 2012 qg42 and laboratory study of possible analog samples |
we have investigated the effect of stellar encounters on the formation and disruption of the oort cloud using the classical impulse approximation. we calculate the evolution of a planetesimal disk into a spherical oort cloud due to the perturbation from passing stars for 10 gyr. we obtain the empirical fits of the e-fo... | effect of stellar encounters on comet cloud formation |
jupiter-family comet 15p/finlay has been reportedly quiet in activity for over a century but has harbored two outbursts during its 2014/2015 perihelion passage. here we present an analysis of these two outbursts using a set of cometary observations. the outbursts took place between 2014 december 15.4-16.0 ut and 2015 j... | bangs and meteors from the quiet comet 15p/finlay |
both centaurs and trans-neptunian objects (tnos) are minor bodies found in the outer solar system. centaurs are a transient population that moves between the orbits of jupiter and neptune, and they probably diffused out of the tnos. tnos move mainly beyond neptune. some of these objects display episodic cometary behavi... | photometry of centaurs and trans-neptunian objects: 2060 chiron (1977 ub), 10199 chariklo (1997 cu26), 38628 huya (2000 eb173), 28978 ixion (2001 kx76), and 90482 orcus (2004 dw) |
the trojan asteroids, orbiting the sun in jupiter's stable lagrange points, provide a unique perspective on the history of our solar system. as a large population of small bodies, they record important gravitational interactions in the dynamical evolution of the solar system. as primitive bodies, their compositions and... | the complex history of trojan asteroids |
context. surveys in the visible and near-infrared spectral range have revealed the presence of low-albedo asteroids in cometary-like orbits (acos). in contrast to jupiter-family comets (jfcs), acos are inactive, but possess similar orbital parameters.aims: in this work, we discuss why acos are inactive, whereas jfcs sh... | why are jupiter-family comets active and asteroids in cometary-like orbits inactive?. how hydrostatic compression leads to inactivity |
in this study, we present high-resolution visible multi-object spectrograph integral field unit spectroscopy (vimos-ifu) of the extremely metal-poor h ii/blue compact dwarf (bcd) galaxy tol 65. the optical appearance of this galaxy shows clearly a cometary morphology with a bright main body and an extended and diffuse ... | on the properties of the interstellar medium in extremely metal-poor blue compact dwarf galaxies. a vimos-ifu study of the cometary galaxy and ly α absorber tol 65 |
metal pollution in white dwarf photospheres originates from the accretion of some combination of planets, moons, asteroids, comets, boulders, pebbles, and dust. when large bodies reside in dynamically stagnant locations - unable themselves to pollute or even closely approach the white dwarf - then smaller reservoirs of... | generating metal-polluting debris in white dwarf planetary systems from small-impact crater ejecta |
recent observations have suggested that there is water ice present on the surfaces of 24 themis and 1 ceres. we present upper limits on the h2o production rate on these bodies derived using a search for [o i]6300 å emission. for themis, the water production is less than 4.5 × 1027 mol s-1 , while for ceres our derived ... | observational constraints on water sublimation from 24 themis and 1 ceres |
aims: we aim to determine whether dissociative excitation of cometary neutrals by electron impact is the major source of far-ultraviolet (fuv) emissions at comet 67p/churyumov-gerasimenko in the southern hemisphere at large heliocentric distances, both during quiet conditions and impacts of corotating interaction regio... | multi-instrument analysis of far-ultraviolet aurora in the southern hemisphere of comet 67p/churyumov-gerasimenko |
the composition of solar system surfaces can be inferred through reflectance and emission spectroscopy, by comparing these observations to laboratory measurements and radiative transfer models. while several populations of objects appear to be covered by sub-micrometre sized particles (d < 1 μm) (referred to as hype... | visible and near-infrared reflectance of hyperfine and hyperporous particulate surfaces |
centaurs are small bodies orbiting in the giant planet region that were scattered inward from their source populations beyond neptune. some members of the population display comet-like activity during their transition through the solar system, the source of which is not well understood. the range of heliocentric distan... | no activity among 13 centaurs discovered in the pan-starrs1 detection database |
the lco outbursting objects key (look) project uses the telescopes of the las cumbres observatory (lco) network to (1) systematically monitor a sample of previously discovered over the whole sky, to assess the evolutionary state of these distant remnants from the early solar system, and (2) use alerts from existing sky... | the lco outbursting objects key project: overview and year 1 status |
the chandra x-ray observatory (chandra) and the x-ray multi-mirror mission (xmm-newton) continue to expand the frontiers of knowledge about high-energy processes in the universe. these groundbreaking observatories lead an x-ray astronomy revolution: revealing the physical processes and extreme conditions involved in pr... | x-ray astronomy comes of age |
precipitation forecasting is an important scientific challenge that has wide-reaching impacts on society. historically, this challenge has been tackled using numerical weather prediction (nwp) models, grounded on physics-based simulations. recently, many works have proposed an alternative approach, using end-to-end dee... | benchmark dataset for precipitation forecasting by post-processing the numerical weather prediction |
we present an in-depth analysis of a time interval when quasi-linear mirror mode structures were detected by magnetic field and plasma measurements as observed by the nasa/mars atmosphere and volatile evolution spacecraft. we employ ion and electron spectrometers in tandem to support the magnetic field measurements and... | making waves: mirror mode structures around mars observed by the maven spacecraft |
high-resolution infrared spectra of comet c/2014 q2 lovejoy were acquired with nirspec at the w. m. keck observatory on two post-perihelion dates (ut 2015 february 2 and 3). h2o was measured simultaneously with co, ch3oh, h2co, ch4, c2h6, c2h4, c2h2, hcn, and nh3 on both dates, and rotational temperatures, production r... | volatile abundances, extended coma sources, and nucleus ice associations in comet c/2014 q2 (lovejoy) |
we present hubble space telescope observations of active asteroid p/2020 o1 taken to examine its development for a year after perihelion. we find that the mass loss peaks at ≲1 kg s-1 in 2020 august and then declines to nearly zero over four months. long-duration mass loss (~180 days) is consistent with a sublimation o... | hubble space telescope observations of active asteroid p/2020 o1 (lemmon-panstarrs) |
the parker solar probe (psp) aims to explore the nascent solar wind close to the sun. meanwhile, psp is also expected to encounter small objects like comets and asteroids. in this work, we survey the ephemerides to find the chance of a recent encounter and then model the interaction between released dusty plasmas and s... | the encounter of the parker solar probe and a comet-like object near the sun: model predictions and measurements |
dust transport and deposition behind larger boulders on the comet 67p/churyumov-gerasimenko (67p/c-g) have been observed by the rosetta mission. we present a mechanism for dust-transport vectors based on a homogeneous surface activity model incorporating in detail the topography of 67p/c-g. the combination of gravitati... | prevailing dust-transport directions on comet 67p/churyumov-gerasimenko |
the analysis of photometrical observations of comet 29p/schwassmann-wachmann 1 is presented. the broadband observations were carried out for 15 nights from 2012 to 2019 at the lisnyky observational station of taras shevchenko national university of kyiv. apparent magnitudes and dust productivity level afρ in filter r w... | photometry of comet 29p/schwassmann-wachmann 1 in 2012-2019 |
we measured the degree of linear polarization of comet c/2020 s3 (erasmus) on 2020 november 13, 20, 22, and 23, while the comet was observed at large phase angles, α = 62.6°-66.6°. on the first two epochs, the polarization closely matched what was previously observed in comet c/1989 x1 (austin). on the third epoch, the... | c/2020 s3 (erasmus): comet with a presumably transient maximum of linear polarization pmax |
in this detailed geochemical, petrological, and microstructural study of felsite clast materials contained in apollo breccia samples 12013, 14321, and 15405, little evidence was found for relatively enriched reservoirs of endogenic lunar volatiles. nanosims measurements have revealed very low volatile abundances (≤ 2-1... | volatiles in lunar felsite clasts: impact-related delivery of hydrous material to an ancient dry lunar crust |
the emission of [o i] lines in the coma of comet 67p/churyumov-gerasimenko during the rosetta mission have been explained by electron impact dissociation of water rather than the process of photodissociation. this is the direct evidence for the role of electron induced processing has been seen on such a body. analysis ... | rosetta mission: electron scattering cross sections—data needs and coverage in beamdb database |
we report photometric observations with las cumbres observatory 1-m sutherland-lcogt c telescope. the observations from 2021 june 22.174 (utc) indicate that the newly discovered 2014 un271 has cometary activity at heliocentric distance of 20.18 au. the observations were done with a panstarrs w-band filter (equivalent t... | newly discovered object 2014 un271 observed as active at 20.18 au |
we monitor the seasonal erosion and accretion of dust deposits in the imhotep, hatmehit, and ma'at regions of comet 67p/churyumov-gerasimenko with osiris narrow angle camera images. the vertical accuracy of such measurements is 0.2 m and the spatial scale of the images we used is lower than 0.60 m pixel-1. we calculate... | long-term measurements of the erosion and accretion of dust deposits on comet 67p/churyumov-gerasimenko with the osiris instrument |
we monitored the comet 67p/churyumov-gerasimenko close to its perihelion in november 2021 with the growth-india telescope. we observed two outbursts of this comet on 2021 october 29.940 and november 17.864 utc, -3.12 days and +15.81 days respectively from the perihelion date. the brightening in the first outburst appea... | outbursts of comet 67p/churyumov-gerasimenko |
aims: the break-up of a dustball meteoroid is investigated numerically based on fluid dynamics simulations of the meteoroid's atmospheric entry flow. both thermal and mechanical break-up mechanisms are implemented, in order to investigate dustball meteoroid disintegration.methods: a three dimensional model of a dustbal... | three dimensional atmospheric entry simulation of a high altitude cometary dustball meteoroid |
answering fundamental questions about the origin and evolution of small planetary bodies hinges on our ability to image their surface and interior structure in detail and at high resolution. the interior structure is not easily accessible without systematic imaging using, e.g., radar transmission and reflection data fr... | 3d radar wavefield tomography of comet interiors |
by using the rosetta/osiris-nac data set taken in 2014 august, we focus on the neck region, called hapi, located on 67p churyumov-gerasimenko's northern hemisphere. the gravitational potential and slopes of hapi, coupled with the geological unit identification and the boulder size-frequency distributions, support the i... | multidisciplinary analysis of the hapi region located on comet 67p/churyumov-gerasimenko |
on 12 november 2014 at 15:34 utc, after a 7-h descent, the philae lander made contact with the surface of the comet churyumov-gerasimenko (67p/cg) in the centre of the intended landing zone. following the failure of its anchoring systems, it bounced and continued to fly ballistically. a couple of hours later, telemetry... | philae localization from consert/rosetta measurement |
in the paper we examine two selected mechanisms of matter ejection from the cometary nuclei. the first is a calm sublimation from the comet's nucleus and the second is the ejection caused by jets produced by cometary geysers. the classical old model which assumes that cometary particles are crumbs of ice-dust solid mat... | selected mechanisms of matter ejection out of the cometary nuclei |
in this study, to better our understanding of the current state of conservation of cardisoma guanhumi and its habitats, we evaluated the potential spatio-temporal genomic damage of this species across five estuaries in brazil. the experiment was performed over two consecutive years, and the sampling was performed in th... | spatial-temporal genome damaging in the blue crab cardisoma guanhumi as ecological indicators for monitoring tropical estuaries |
the a2πi state of 12c16o+ has been reinvestigated using high-resolution, emission spectra obtained via fourier-transform spectroscopy of the (0, 1), (0, 2), (1, 0) and (1, 1) bands of the comet-tail (a2πi - x2σ+) system with accuracy of up to 0.005 cm-1. the high temperature (900 k) of the emission discharge inside the... | fourier-transform spectroscopy of the a2πi - x2σ+ system in co+ and deperturbation analysis of the a2πi(v = 0, 1) levels |
the origin of cometary volatiles remains a major open question in planetary science. comets may have either agglomerated from crystalline ices condensed in the protosolar nebula (psn) or from amorphous ice originating from the molecular cloud and interstellar medium. here, based on the recent argon, krypton, and xenon ... | noble gas abundance ratios indicate the agglomeration of 67p/churyumov-gerasimenko from warmed-up ice |
context. main belt comets are a recently identified population of minor bodies with stable asteroid-like orbits but cometary appearances. sublimation of water ice is the most likely mechanism for their recurrent activity (i.e. dust tails and dust comae), although there has been no direct detection of gas. these peculia... | x-shooter search for outgassing from main belt comet p/2012 t1 (pan-starrs) |
during five nights between february 3 and 10, 2021, we monitored the degree of linear polarization in comet 29p/schwassmann-wachmann with the broadband r filter. it is the first polarimetric investigation of this comet measured during a period of quiescent activity. we found a nearly constant negative polarization pq ≈... | monitoring the negative polarization in comet 29p/schwassmann-wachmann during quiescence |
asteroids (24) themis and (65) cybele have an absorption feature at 3.1 μm reported to be directly linked to surface water ice. we searched for water vapor escaping from these asteroids with the herschel space observatory heterodyne instrument for the far infrared. while no h2o line emission was detected, we obtain sen... | low water outgassing from (24) themis and (65) cybele: 3.1 μm near-ir spectral implications |
on the orbiter of the rosetta spacecraft, the cometary secondary ion mass analyser (cosima) will provide new in situ insights about the chemical composition of cometary grains all along 67p/churyumov-gerasimenko (67p/cg) journey until the end of december 2015 nominally. the aim of this paper is to present the pre-calib... | cosima calibration for the detection and characterization of the cometary solid organic matter |
all atmosphere-less planetary bodies are covered with a dust layer, the so-called regolith, which determines the optical, mechanical and thermal properties of their surface. these properties depend on the regolith material, the size distribution of the particles it consists of, and the porosity to which these particles... | the stratification of regolith on celestial objects |
the shape of the heliosphere is thought to resemble a long, comet tail, however, recently it has been suggested that the heliosphere is tailless with a two-lobe structure. the latter study was done with a three-dimensional (3d) magnetohydrodynamic code, which treats the ionized and neutral hydrogen atoms as fluids. pre... | the impact of kinetic neutrals on the heliotail |
images and low-resolution spectra of the near-earth jupiter family comet (jfc) 249p/linear in the visible range obtained with the instrument osiris in the 10.4 m gran telescopio canarias (gtc) (la palma, spain) on january 3, 4, 6 and february 6, 2016 are presented, together with a series of images obtained with the 0.4... | physical and dynamical properties of the anomalous comet 249p/linear |
context. n2 is rarely found in comets, or when it is present, it is found only in small quantities despite its abundance on the surfaces of different outer solar system objects. a few comets presented n2+ emission lines in their optical spectra. one of them, c/2016 r2, showed an unusually high abundance of this species... | n2+ fluorescence spectrum of comet c/2016 r2 (panstarrs) |
comet 21p/giacobini-zinner (hereafter, comet 21p/g-z) is a jupiter-family comet and a parent comet of the october draconids meteor shower. if meteoroids originating from a jupiter-family comet contain complex organic molecules, such as amino acids, they are essential pieces of the puzzle regarding the origin of life on... | unidentified infrared emission features in mid-infrared spectrum of comet 21p/giacobini-zinner |
we investigate numerically and analytically size-polydisperse granular mixtures immersed into a molecular gas. we show that the equipartition of granular temperatures of particles of different sizes is established; however, the granular temperatures significantly differ from the temperature of the molecular gas. this r... | size-polydisperse dust in molecular gas: energy equipartition versus nonequipartition |
aims: we investigate the surface distribution of the source regions of dust jets on comet 67p/churyumov-gerasimenko as a function of time.methods: the dust jet source regions were traced by the comprehensive imaging data set provided by the osiris scientific camera.results: we show in detail how the projected footpoint... | seasonal variations in source regions of the dust jets on comet 67p/churyumov-gerasimenko |
biological effect directed in vivo tests with model organisms are useful in assessing potential health risks associated with chemical contaminations in surface waters. this study examined the applicability of two in vivo test systems viz. plant, allium cepa root based tests and fish, oreochromis niloticus erythrocyte b... | cytogenotoxicity screening of source water, wastewater and treated water of drinking water treatment plants using two in vivo test systems: allium cepa root based and nile tilapia erythrocyte based tests |
this paper is a phenomenological description of multispacecraft observations of energetic particles caused by the close flyby of comet c/2013 a1 siding spring with mars on 19 october 2014. this is the first time that cometary energetic particles have been observed at mars. the mars atmosphere and volatile evolution (ma... | energetic particle showers over mars from comet c/2013 a1 siding spring |
since its launch in 1990, the hubble space telescope (hst) has served as a platform with unique capabilities for remote observations of comets in the far-ultraviolet region of the spectrum. successive generations of imagers and spectrographs have seen large advances in sensitivity and spectral resolution enabling obser... | far-ultraviolet spectroscopy of recent comets with the cosmic origins spectrograph on the hubble space telescope |
a recent study by opher et al. suggested the heliosphere has a “croissant” shape, where the heliosheath plasma is confined by the toroidal solar magnetic field. the “croissant” heliosphere is in contrast to the classically accepted view of a comet-like tail. we investigate the effect of the “croissant” heliosphere mode... | globally distributed energetic neutral atom maps for the “croissant” heliosphere |
the study of exospheres can help us understand the long-term loss of volatiles from planetary bodies due to interactions of planets, satellites, and small bodies with the interplanetary medium, solar radiation, and internal forces including diffusion and outgassing. recent evidence for water and oh on the moon has spur... | exospheric escape: a parametrical study |
context. on 27 april 2015, when comet 67p/churyumov-gerasimenko was at 1.76 au from the sun and moving toward perihelion, the osiris and virtis-m instruments on board the rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet.aims: we aim to characterize the sp... | diurnal variation of dust and gas production in comet 67p/churyumov-gerasimenko at the inbound equinox as seen by osiris and virtis-m on board rosetta |
we present results from our 47 night imaging campaign of comet 41p/tuttle-giacobini-kresák conducted from lowell observatory between 2017 february 16 and july 2. coma morphology revealed gas jets, whose appearance and motion as a function of time yielded the rotation period and other properties. all narrowband cn image... | gas jet morphology and the very rapidly increasing rotation period of comet 41p/tuttle-giacobini-kresák |
in 2017 observers of the "churyumov's unified network" from april 15 to 26 registered more than a hundred tracks of daytime lyrid's invasions. the maximum number (18) of daily invasions of lyrids we observed on april 19. tracks had a length of 5 deg. up to 30 deg. some of them were short, thin and rapidly disappearing ... | daytime observations of lyrids in 2017 |
context. solar wind charge-changing reactions are of paramount importance to the physico-chemistry of the atmosphere of a comet, mass-loading the solar wind through an effective conversion of fast light solar wind ions into slow heavy cometary ions.aims: to understand these processes and place them in the context of a ... | solar wind charge exchange in cometary atmospheres. i. charge-changing and ionization cross sections for he and h particles in h2o |
for the last two decades, we have been observing a huge increase in discoveries of long-period comets (lpcs), especially those with large perihelion distances. we collected data for a full sample of lpcs discovered during 1801-2017, including their osculating orbits, discovery moments (to study the discovery distances)... | discovery statistics and 1/a distribution of long-period comets detected during 1801-2017 |
low-gravity waterworlds (m ≲ 0.1 m ⊕) are of interest for their potential habitability. the weakly bound atmospheres of such worlds have proportionally larger radiative surfaces and are more susceptible to escape. we conduct a unified investigation into these phenomena, combining analytical energy balance and hydrodyna... | atmospheric evolution on low-gravity waterworlds |
the organization of the orbits of most minor bodies in the solar system seems to follow random patterns, the result of billions of years of chaotic dynamical evolution. much as heterogeneous orbital behaviour is ubiquitous, dynamically coherent pairs and groups of objects are also present everywhere. although first stu... | dynamically correlated minor bodies in the outer solar system |
the outbursts of comets, sudden large increases in their luminosity, are still very interesting and mysterious signs of activity of this celestial bodies. most of the cometary outbursts are taking place at heliocentric distances where sublimation of water ice plays an important role in the activity of comets. however, ... | a review of cometary outbursts at large heliocentric distances |
main-belt asteroid (6478) gault was observed to show cometary features in early 2019. to investigate the cause, we conducted bvr observations at xingming observatory, china, from 2019 january to april. the two tails were formed around 2018 october 26-november 8, and 2018 december 29-2019 january 8, respectively, and co... | new active asteroid (6478) gault |
we investigate the centimeter-to-decimeter-scale particle size distribution and dynamics in the coma of comet 73p/schwassmann-wachmann 3 using radar observations obtained shortly after the comet's disintegration in may 2006. we derive the particle size distribution power-law index in the comae of fragments b and c usin... | decimeter-scale particle characterization in the coma of 73p/schwassmann-wachmann 3 using dual-wavelength radar observations |
on the night of october 31, 2015 two bright southern taurid fireballs occurred over poland, being one of the most spectacular bolides of this shower in recent years. the first fireball - pf311015a okonek - was detected by six video stations of polish fireball network (pfn) and photographed by several bystanders, allowi... | 2015 southern taurid fireballs and asteroids 2005 ur and 2005 tf50 |
given that a strong 14c variation in ad 775 has recently been suggested to be due to the largest solar flare ever recorded in history, it is relevant to investigate whether celestial events observed around that time may have been aurorae, possibly even very strong aurorae, or otherwise related to the 14c variation (e.g... | a review of east asian reports of aurorae and comets circa ad 775 |
topic of this work are comets, small and elusive objects that may hold great secrets about the origin of the solar system and life on earth, being among the most primitive objects. the method of investigation addressed in this work is the visible and infrared spectrophotometry by imaging spectrometers, designed for the... | spectrophotometric analysis of cometary nuclei from in situ observations (phd thesis) |
context. the thermal conductivity of highly porous dust aggregates is a key parameter for many subjects in planetary science; it is not yet fully understood, however.aims: we investigate the thermal conductivity of fluffy dust aggregates with filling factors lower than 10-1.methods: we determined the temperature struct... | thermal conductivity of porous aggregates |
many asymptotic giant branch (agb) and supergiant stars exhibit extended detached shells in the far-infrared, resembling rings or arcs. these structures have long been interpreted as the bow shock formed in the interface between the stellar wind and the interstellar medium (ism), the astrosphere. to date, only a few ag... | a large bubble around the agb star r dor detected in the uv |
the cometary secondary ion mass analyzer (cosima) onboard esa's rosetta orbiter has revealed that dust particles in the coma of comet 67p/churyumov-gerasimenko are aggregates of small grains. we study the morphological, elastic, and electric properties of dust aggregates in the coma of comet 67p/churyumov-gerasimenko u... | the morphological, elastic, and electric properties of dust aggregates in comets: a close look at cosima/rosetta's data on dust in comet 67p/churyumov-gerasimenko |
at discovery time, c/2017 k2 (panstarrs) was the second most distant inbound active comet ever observed. it has been argued that this object is in the process of crossing the inner solar system for the first time, but other authors have concluded that it is dynamically old. we have performed full n-body simulations for... | comet c/2017 k2 (panstarrs): dynamically old or new? |
we present an optical and near-infrared (hereafter nir) polarimetric study of a comet c/2013 us10 (catalina) observed on ut 2015 december 17-18 at phase angles of α = 52.°1-53.°1. additionally, we obtained an optical spectrum and multi-band images to examine the influence of gas emission. we find that the observed opti... | optical and near-infrared polarimetry of non-periodic comet c/2013 us10 (catalina) |
the physical composition and structure of meteoroids gives us insight into the formation processes of their parent asteroids and comets. the strength of and fundamental grain sizes in meteoroids tell us about the environment in which small solar system bodies formed, and the processes which built up these basic planeta... | meteoroid structure and fragmentation |
carbonaceous chondrite meteorites are some of the oldest solar system planetary materials available for study. the ci group has bulk abundances of elements similar to those of the solar photosphere. of particular interest in carbonaceous chondrite compositions are labile elements, which vaporize and mobilize efficientl... | thermal alteration of labile elements in carbonaceous chondrites |
133p/elst-pizarro is the first recognized main-belt comet, but we still know little about its nucleus. first we use mid-infrared data of spitzer mips, spitzer irs, and the wide-field infrared survey explorer to estimate its effective diameter, ${d}_{\mathrm{eff}}={3.9}_{-0.3}^{+0.4}$ km, geometric albedo, ${p}_{{\rm{v}... | low-activity main-belt comet 133p/elst-pizarro: new constraints on its albedo, temperature, and active mechanism from a thermophysical perspective |
context. solar orbiter is expected to have flown close to the tail of comet c/2019 y4 (atlas) during the spacecraft's first perihelion in june 2020. models predict a possible crossing of the comet tails by the spacecraft at a distance from the sun of approximately 0.5 au.aims: this study is aimed at identifying possibl... | solar orbiter's encounter with the tail of comet c/2019 y4 (atlas): magnetic field draping and cometary pick-up ion waves |
glass with embedded metal and sulfides (gems) is a major component of chondritic porous interplanetary dust particles. although gems is one of the most primitive components in the solar system, its formation process and conditions have not been constrained. we performed condensation experiments of gases in the system o... | condensation of cometary silicate dust using an induction thermal plasma system. i. enstatite and ci chondritic composition |
equipping a spacecraft with multiple solar-powered electric engines (of the same or different types) compounds the task of optimal trajectory design due to presence of both real-valued inputs (power input to each engine in addition to the direction of thrust vector) and discrete variables (number of active engines). ea... | a novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 2 |
the virtis imaging spectrometer on board rosetta has shown that the nucleus surface of comet 67p/churyumov-gerasimenko (67p/cg) is characterized by a broad absorption band at around 3.2 μm. the feature is ubiquitous across the surface and its attribution to (a) specific material(s) has been challenging. in the present ... | hydroxylated mg-rich amorphous silicates: a new component of the 3.2 μm absorption band of comet 67p/churyumov-gerasimenko |
the current composition of giant planet atmospheres provides information on how such planets formed, and on the origin of the solid building blocks that contributed to their formation. noble gas abundances and their isotope ratios are among the most valuable pieces of evidence for tracing the origin of the materials fr... | tracing the origins of the ice giants through noble gas isotopic composition |
context. the esa rosetta mission has allowed for an extensive in situ study of the comet 67p/churyumov-gerasimenko. in measurements performed by the ram gauge of the comet pressure sensor (cops), observed features are seen to deviate from the nominal ram gauge signal. this effect is attributable to the sublimation of t... | detection of volatiles undergoing sublimation from 67p/churyumov-gerasimenko coma particles using rosina/cops. i. the ram gauge |
the recent observations show that comet c/2016 r2 (pan-starrs) has a unique and peculiar composition when compared with several other comets observed at 2.8 au heliocentric distance. assuming solar resonance fluorescence is the only excitation source, the observed ionic emission intensity ratios are used to constrain t... | a physico-chemical model to study the ion density distribution in the inner coma of comet c/2016 r2 (pan-starrs) |
in this work we present the experimental verification of different approaches to calculate the rate of the outgassing of cometary analogues. we investigated both new, and known formulations applicable for the mass flux of water vapor from mixtures of ice agglomerates. for the purpose of the verification we performed ex... | outgassing of ice agglomerates |
the relation between ice composition in the nucleus of comet 67p/churyumov-gerasimenko on the one hand and relative abundances of volatiles in the coma on the other hand is important for the interpretation of density measurements in the environment of the cometary nucleus. for the 2015 apparition, in situ measurements ... | the ice composition close to the surface of comet 67p/churyumov-gerasimenko |
highly periodic structures are often said to convey the beauty of nature. however, most material properties are strongly influenced by the defects they contain. on the mesoscopic scale, molecular self-assembly exemplifies this interplay; thermodynamic principles determine short-range order, but long-range order is main... | high-resolution three-dimensional imaging of topological textures in single-diamond networks |
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