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the discovery of 2012 vp113 initiated the debate on the origin of the sedna family of planetesimals in orbit around the sun. sednitos roam the outer regions of the solar system between the egeworth-kuiper belt and the oort cloud, in extraordinary wide (a > 150 au) orbits with a large perihelion distance of q > 30... | how sedna and family were captured in a close encounter with a solar sibling |
in the analysis of thermal infrared data of asteroids by means of thermophysical models (tpms) it is a common practice to neglect the uncertainty of the shape model and the rotational state, which are taken as an input for the model. here, we present a novel method of investigating the importance of the shape model and... | thermophysical modeling of asteroids from wise thermal infrared data - significance of the shape model and the pole orientation uncertainties |
with the recent discovery of transiting planetary material around wd 1145+017, a critical target has been identified that links the evolution of planetary systems with debris disks and their accretion onto the star. we present a series of observations, five epochs over a year, taken with keck and the vlt, which for the... | spectroscopic evolution of disintegrating planetesimals: minute to month variability in the circumstellar gas associated with wd 1145+017 |
sunskirting asteroid (3200) phaethon has been repeatedly observed in solar terrestrial relations observatory (stereo) heliospheric imager 1 (hi1) imagery to anomalously brighten and produce an antisunward tail for a few days near each perihelion passage, phenomena previously attributed to the ejection of micron-sized d... | sodium brightening of (3200) phaethon near perihelion |
the first interstellar object, ‘oumuamua, was discovered in the solar system by pan-starrs in 2017, allowing for a calibration of the abundance of interstellar objects of its size and an estimation of the subset of objects trapped by the jupiter-sun system. photographing or visiting these trapped objects would allow us... | identifying interstellar objects trapped in the solar system through their orbital parameters |
context. a high fraction of carbon bound in solid carbonaceous material is observed to exist in bodies formed in the cold outskirts of the solar nebula, while bodies in the region of terrestrial planets contain only very small mass fractions of carbon. most of the solid carbon component is lost and converted into co du... | spatial distribution of carbon dust in the early solar nebula and the carbon content of planetesimals |
proximity observations by osiris-rex and hayabusa2 provided clues on the shape evolution processes of the target asteroids, (101955) bennu and (162173) ryugu. their oblate shapes with equatorial ridges, or the so-called top shapes, may have evolved due to their rotational conditions at present and in the past. differen... | spin-driven evolution of asteroids' top-shapes at fast and slow spins seen from (101955) bennu and (162173) ryugu |
the acm multimedia 2023 computational paralinguistics challenge addresses two different problems for the first time in a research competition under well-defined conditions: in the emotion share sub-challenge, a regression on speech has to be made; and in the requests sub-challenges, requests and complaints need to be d... | the acm multimedia 2023 computational paralinguistics challenge: emotion share & requests |
solar system small bodies were the first objects to accrete inside the protoplanetary disk, giving insights into its composition and structure. the p-/d-type asteroids are particularly interesting because of the similarity of their spectra, at visible and near infrared wavelengths (vis-nir), with cometary nuclei, sugge... | reflection, emission, and polarization properties of surfaces made of hyperfine grains, and implications for the nature of primitive small bodies |
this paper proposes a novel adaptive guidance system developed using reinforcement meta-learning with a recurrent policy and value function approximator. the use of recurrent network layers allows the deployed policy to adapt in real time to environmental forces acting on the agent. we compare the performance of the dr... | adaptive guidance and integrated navigation with reinforcement meta-learning |
space weathering alters the optical properties of exposed surfaces over time, complicating the interpretation of spectroscopic observations of airless bodies like asteroids, mercury, and the moon. solar wind and micrometeoroids are likely the dominant agents of space weathering, but their relative contributions are not... | latitudinal variation in spectral properties of the lunar maria and implications for space weathering |
landslides have been observed in different terrestrial environments and also on planets, satellites, and asteroids. long runout landslides are strongly dependent on the initial mass position, material and slope path properties, topographic relief, and presence of volatiles. therefore, landslides represent a means for t... | introducing a new inventory of large martian landslides |
by means of a varied-shape thermophysical model of hanuš et al. (2015) that takes into account asteroid shape and pole uncertainties, we analyze the thermal infrared data acquired by the nasa's wide-field infrared survey explorer of about 300 asteroids with derived convex shape models. we utilize publicly available con... | thermophysical modeling of main-belt asteroids from wise thermal data |
to characterize the meteoroid environment around mercury and its contribution to the planet’s exosphere, we combined four distinctive sources of meteoroids in the solar system: main-belt asteroids, jupiter-family comets, halley-type comets, and oort cloud comets. all meteoroid populations are described by currently ava... | a comprehensive model of the meteoroid environment around mercury |
this is a pilot paper serving as a launching pad for study of orbital and spin evolution of binary asteroids. the rate of tidal evolution of asteroidal binaries is defined by the dynamical love numbers kl divided by quality factors q. common in the literature is the (oftentimes illegitimate) approximation of the dynami... | tidal evolution of asteroidal binaries. ruled by viscosity. ignorant of rigidity. |
wide-field microscopy of optically thick specimens typically features reduced contrast due to spatial cross-talk, in which the signal at each point in the field of view is the result of a superposition from neighbouring points that are simultaneously illuminated. in 1955, marvin minsky proposed confocal microscopy as a... | artificial confocal microscopy for deep label-free imaging |
interplanetary dust particles are important samples of dust-producing objects in the solar system, including many primitive and organic-rich bodies that are not sampled by known meteorites. interplanetary dust particles spiral in towards the sun under the influence of poynting-robertson drag forces and are exposed to s... | evidence for a significant kuiper belt dust contribution to the zodiacal cloud |
occator crater is perhaps the most distinct surface feature observed by nasa's dawn spacecraft on the cerean surface. contained within the crater are the highest albedo features on the planet, cerealia facula and vinalia faculae, and relatively smooth lobate flow deposits. we present hydrocode simulations of the format... | post-impact thermal structure and cooling timescales of occator crater on asteroid 1 ceres |
successful sampling on asteroids is challenging due to their weightless environment and unknown material mechanical properties. this work presents a sweeping and grinding combined hybrid sampler (sghs) to improve the sampling success rate. the sghs has two working modes, i.e., using two brush wheels to collect regolith... | a sweeping and grinding combined hybrid sampler for asteroid sample return mission |
recent investigations of meteorites thought to originate from the asteroid 4 vesta have suggested an early accretion of water on rocky bodies in the inner solar system from a carbonaceous chondrite-like source. however, these studies have been based on the hydrogen isotope compositions (δd) of late-crystallizing apatit... | a deuterium-poor water reservoir in the asteroid 4 vesta and the inner solar system |
benthic foraminifera are the most common meiofaunal unicellular deep-sea biota, forming skeletons used as proxies for past climate change. we aim to increase understanding of past non-analog oceans and ecosystems by evaluating deep-sea benthic foraminiferal responses to global environmental changes over latest cretaceo... | turnover and stability in the deep sea: benthic foraminifera as tracers of paleogene global change |
the hadean history of earth is shrouded in mystery and it is considered that the planet was born dry with no water or atmosphere. the earth-moon system had many features in common during the birth stage. solidification of the dry magma ocean at 4.53 ga generated primordial continents with komatiite. we speculate that t... | hadean earth and primordial continents: the cradle of prebiotic life |
near-earth asteroid (101955) bennu is an active asteroid experiencing mass loss in the form of ejection events emitting up to hundreds of millimeter- to centimeter-scale particles. the close proximity of the origins, spectral interpretations, resource identification, and security-regolith explorer spacecraft enabled mo... | photometry of particles ejected from active asteroid (101955) bennu |
context. gaia is europe's space astrometry mission, aiming to make a three-dimensional map of 1000 million stars in our milky way to unravel its kinematical, dynamical, and chemical structure and evolution.aims: we present a study of gaia's detection capability of objects, in particular non-saturated stars, double star... | detecting stars, galaxies, and asteroids with gaia |
roughly 1000 white dwarfs are known to be polluted with planetary material, and the progenitors of this material are typically assumed to be asteroids. the dynamical architectures which perturb asteroids into white dwarfs are still unknown, but may be crucially dependent on moons liberated from parent planets during po... | the fate of exomoons in white dwarf planetary systems |
the main motivation of this research is the analytical exploration of the dynamics of asteroid rotation when it moves in elliptic orbit through space. according to the results of efroimsky, frouard (2016), various perturbations (collisions, close encounters, yorp effect) destabilize the rotation of a small body (astero... | the dynamics of asteroid rotation, governed by yorp effect: the kinematic ansatz |
dynamicalmass estimates for the main asteroid belt and the trans-neptunian kuiper belt have been found from their gravitational influence on the motion of planets. discrete rotating models consisting ofmovingmaterial points have been used tomodel the total attraction fromsmall or as yet undetected bodies of the belts. ... | masses of the main asteroid belt and the kuiper belt from the motions of planets and spacecraft |
the burrows-wheeler transform (bwt) is an invertible text transformation that permutes symbols of a text according to the lexicographical order of its suffixes. bwt is the main component of popular lossless compression programs (such as bzip2) as well as recent powerful compressed indexes (such as $r$-index [gagie et a... | resolution of the burrows-wheeler transform conjecture |
we present experimental phase function and degree of linear polarization curves for seven samples of cometary dust analogues namely: ground pieces of allende, dag521, fro95002, and fro99040 meteorites, mg-rich olivine and pyroxene, and a sample of organic tholins. the experimental curves have been obtained at the iaa c... | experimental phase function and degree of linear polarization of cometary dust analogues |
in this work we combine several constraints provided by the crater records on arrokoth and the worlds of the pluto system to compute the size-frequency distribution (sfd) of the crater production function for craters with diameter d ≲ 10 km. for this purpose, we use a kuiper belt objects (kbo) population model calibrat... | a re-assessment of the kuiper belt size distribution for sub-kilometer objects, revealing collisional equilibrium at small sizes |
protoplanetary disks are dust-rich structures around young stars. the crystalline and amorphous materials contained within these disks are variably thermally processed and accreted to make bodies of a wide range of sizes and compositions, depending on the heliocentric distance of formation. the chondritic meteorites ar... | accretion of water in carbonaceous chondrites: current evidence and implications for the delivery of water to early earth |
the ci and ci-like chondrites provide a record of aqueous alteration in the early solar system. however, the ci-like chondrites differ in having also experienced a late stage period of thermal metamorphism. in order to constrain the nature and extent of the aqueous and thermal alteration, we have investigated the bulk ... | characterising the ci and ci-like carbonaceous chondrites using thermogravimetric analysis and infrared spectroscopy |
as the largest magmatic iron meteorite group, the iiiab group is often used to investigate the process of core crystallization in asteroid-sized bodies. however, previous iiiab crystallization models have not succeeded in both explaining the scatter among iiiab irons around the main crystallization trends and using ele... | a revised trapped melt model for iron meteorites applied to the iiiab group |
the binary asteroid 65803 didymos-dimorphos is the target of the first asteroid deflection test (nasa's double asteroid redirection test, dart) and the first binary asteroid system that will be characterized by a rendezvous mission (esa's hera). the cohesive strength of the fast-spin-primary didymos is a key factor tha... | creep stability of the dart/hera mission target 65803 didymos: ii. the role of cohesion |
the origin of the diverse organic compounds present in carbonaceous chondrites (cc) remains uncertain. we aim at investigating the role that hydrothermal alteration may have had on the molecular evolution of organic matter (om). in particular, within cc matrices, om is intimately embedded within phyllosilicates down to... | influence of phyllosilicates on the hydrothermal alteration of organic matter in asteroids: experimental perspectives |
the collapse of dust particle clouds directly to kilometer-sized planetesimals is a promising way to explain the formation of planetesimals, asteroids, and comets. in the past, this collapse has been studied in stratified shearing box simulations with super-solar dust-to-gas ratio ɛ, allowing for streaming instability ... | azimuthal and vertical streaming instability at high dust-to-gas ratios and on the scales of planetesimal formation |
spacecraft observations of atmosphereless solar system bodies, combined with thermophysical modeling, provide important information about the thermal inertia and degree of surface roughness of these bodies. the thermophysical models rely on various methods of generating topography, the most common being the concave sph... | interpretation of thermal emission. i. the effect of roughness for spatially resolved atmosphereless bodies |
magnesium-rich silicate chondrules and calcium-, aluminum-rich refractory inclusions (cais) are fundamental components of primitive chondritic meteorites. it has been suggested that concentration of these early-formed particles by nebular sorting processes may lead to accretion of planetesimals, the planetary bodies th... | particle size distributions in chondritic meteorites: evidence for pre-planetesimal histories |
the ubvri broad band photometric system is widely used in ccd astronomy. there are a lot of sets of standard stars for this photometric system, the landolt's and stetson's catalogues being the most precise and reliable. another photometric system, recently considerably spread in ccd observations is ugriz, which origina... | transformation of pan-starrs1 gri to stetson bvri magnitudes. photometry of small bodies observations. |
hayabusa2 is a sample return mission of jaxa launched on 3 december 2014. hayabusa2 is the successor of hayabusa, which returned samples from the asteroid itokawa to the earth. although the design of hayabusa2 follows that of hayabusa, the former is equipped with some new components. the small carry-on impactor (sci) i... | the small carry-on impactor (sci) and the hayabusa2 impact experiment |
prior to the arrival of the dawn spacecraft at ceres, the dwarf planet was anticipated to be ice-rich. searches for morphological features related to ice have been ongoing during dawn's mission at ceres. here we report the identification of pitted terrains associated with fresh cerean impact craters. the cerean pitted ... | pitted terrains on (1) ceres and implications for shallow subsurface volatile distribution |
near-earth objects (neos) that orbit the sun on or within earth's orbit are tricky to detect for earth-based observers due to their proximity to the sun in the sky. these small bodies hold clues to the dynamical history of the inner solar system as well as the physical evolution of planetesimals in extreme environments... | a twilight search for atiras, vatiras, and co-orbital asteroids: preliminary results |
planets and minor bodies such as asteroids, kuiper-belt objects, and comets are integral components of a planetary system. interactions among them leave clues about the formation process of a planetary system. the signature of such interactions is most prominent through observations of its debris disk at millimeter wav... | alma 1.3 mm map of the hd 95086 system |
understanding the fate of planetary systems through white dwarfs which accrete debris crucially relies on tracing the orbital and physical properties of exo-asteroids during the giant branch phase of stellar evolution. giant branch luminosities exceed the sun's by over three orders of magnitude, leading to significantl... | speeding past planets? asteroids radiatively propelled by giant branch yarkovsky effects |
dawn's framing camera observed boulders on the surface of vesta when the spacecraftwas in its lowest orbit (low altitude mapping orbit, lamo). we identified, measured, and mapped boulders in lamo images, which have a scale of 20 m per pixel. we estimate that our sample is virtually complete down to a boulder size of 4 ... | the boulder population of asteroid 4 vesta: size frequency distribution and survival time |
context. the centaur (10199) chariklo has the first ring system discovered around a small object. it was first observed using stellar occultation in 2013. stellar occultations allow sizes and shapes to be determined with kilometre accuracy, and provide the characteristics of the occulting object and its vicinity.aims: ... | refined physical parameters for chariklo's body and rings from stellar occultations observed between 2013 and 2020 |
hayabusa2 is the japanese asteroid return mission and targeted the carbonaceous asteroid ryugu, conducted by the japan aerospace exploration agency (jaxa). the goal of this mission was to conduct proximity operations including remote sensing observations, material sampling, and a small carry-on impact experiment, as we... | hayabusa2 extended mission: new voyage to rendezvous with a small asteroid rotating with a short period |
context. the nasa mission osiris-rex (origins, spectral interpretation, resource identification, and security-regolith explorer) has been observing near-earth asteroid (101955) bennu in close proximity since december 2018. in october 2020, the spacecraft collected a sample of surface material from bennu to return to ea... | phase reddening on asteroid bennu from visible and near-infrared spectroscopy |
one of the key goals of the rosetta mission was to understand how, where and when comets formed in our solar system. there are two major hypotheses for the origin of comets, both pre-rosetta: (1) hierarchical accretion of dust and ice grains in the solar nebula and (2) the growth of pebbles, which are then brought toge... | origin and evolution of cometary nuclei |
dujmović, joret, micek, morin, ueckerdt and wood [j. acm 2020] proved that for every graph $g$ with euler genus $g$ there is a graph $h$ with treewidth at most 4 and a path $p$ such that $g\subseteq h \boxtimes p \boxtimes k_{\max\{2g,3\}}$. we improve this result by replacing "4" by "3" and with $h$ planar. we in fact... | improved product structure for graphs on surfaces |
the field of asteroid thermophysical modeling has experienced an extraordinary growth in the last 10 years, as new thermal-infrared data became available for hundreds of thousands of asteroids. the infrared emission of asteroids depends on the body's size, shape, albedo, thermal inertia, roughness, and rotational prope... | asteroid thermophysical modeling |
this paper proposes a new global and local weighted signed pressure force (spf) based active contour model (acm) to segment various types of images. first, by introducing the normalized global minimum absolute differences as the coefficients of global inner and outer region fitting centers, a new global weighted spf (g... | active contours driven by global and local weighted signed pressure force for image segmentation |
the recent detection of the gravitational-wave source gw150914 by the ligo collaboration motivates a speculative source for the origin of ultrahigh-energy cosmic rays as a possible byproduct of the immense energies achieved in black hole (bh) mergers, provided that the bhs have spin, as seems inevitable, and there are ... | ultrahigh-energy cosmic rays and black hole mergers |
the near-earth asteroid (3200) phaethon is the parent body of the geminid meteor stream. phaethon is also an active asteroid with a very blue spectrum. we conducted polarimetric observations of this asteroid over a wide range of solar phase angles α during its close approach to the earth in autumn 2016. our observation... | extremely strong polarization of an active asteroid (3200) phaethon |
the 90.5-km occator crater, with its peculiar and unique bright spots, is one of the most prominent and renowned feature on ceres. occator attracted broad public attention in scientific media as it is proposed to exhibit signs of post-impact cryovolcanic activity. in order to understand the time sequence of deposition,... | the various ages of occator crater, ceres: results of a comprehensive synthesis approach |
early solar system planetesimal thermal models predict the heating of the chondritic protolith and the preservation of a chondritic crust on differentiated parent bodies. petrological and geochemical analyses of chondrites have suggested that secondary alteration phases formed at low temperatures (<300 °c) by fluid-... | reduced and unstratified crust in cv chondrite parent body |
the hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-earth asteroid 162173 ryugu. hayabusa2 successfully landed on its surface and ejected a projectile for sample collection on february 22, 2019. hayabusa2 later landed near a crater formed by an impactor and executed the sam... | modeling and analysis of hayabusa2 touchdown |
there is abundant petrologic evidence for the oxidation of fe during the aqueous alteration of chondrites, and water must have been the oxidant for this process. the h2 lost from the chondrite parent bodies as a result of fe oxidation would have been isotopically very light, enriching any residual water in d. the exten... | the bulk valence state of fe and the origin of water in chondrites |
recent theoretical work in celestial mechanics has revealed that an asteroid may orbit stably in the same region as a planet, despite revolving around the sun in the sense opposite to that of the planet itself. asteroid 2015 bz509 was discovered in 2015, but with too much uncertainty in its measured orbit to establish ... | a retrograde co-orbital asteroid of jupiter |
in the preliminary trajectory design of the multi-target rendezvous problem, a model that can quickly estimate the cost of the orbital transfer is essential. the estimation of the transfer time using solar sails between two arbitrary orbits is difficult and usually requires to solve an optimal control problem. inspired... | solar-sail trajectory design for multiple near-earth asteroid exploration based on deep neural networks |
many isolated, old white dwarfs (wds) show surprising evidence of metals in their photospheres. given that the timescale for gravitational sedimentation is astronomically short, this is taken as evidence for ongoing accretion, likely of tidally disrupted planetesimals. the rate of such accretion, {\dot{m}}acc}, is impo... | increases to inferred rates of planetesimal accretion due to thermohaline mixing in metal-accreting white dwarfs |
rozitis et al. recently reported that near-earth asteroid (29075) 1950 da, whose bulk density ranges from 1.0 g cm-3 to 2.4 g cm-3, is a rubble pile and requires a cohesive strength of at least 44-76 pa to keep from failing due to its fast spin period. since their technique for giving failure conditions required the av... | stress and failure analysis of rapidly rotating asteroid (29075) 1950 da |
we introduce a constrained nonlinear least-squares algorithm to be used in estimating the parameters in the h, g1, g2 phase function. as the algorithm works directly in the magnitude space, it will surpass the possible bias problem that may be present in the existing h ,g1 ,g2 fit procedure when applied to low-accuracy... | h, g1, g2 photometric phase function extended to low-accuracy data |
in this work we have estimated 10 collisional ages of 9 families for which for different reasons our previous attempts failed. in general, these are difficult cases that required dedicated effort, such as a new family classifications for asteroids in mean motion resonances, in particular the 1/1 and 2/1 with jupiter, a... | on the ages of resonant, eroded and fossil asteroid families |
context. the high-angular-resolution capability of the new-generation ground-based adaptive-optics camera sphere at eso vlt allows us to assess, for the very first time, the cratering record of medium-sized (d 100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt... | 3d shape of asteroid (6) hebe from vlt/sphere imaging: implications for the origin of ordinary h chondrites |
determining the size and orbital distribution of the population of near-earth asteroids (neas) is the focus of intense research, with the most recent models converging to a population of approximately 1000 neas larger than 1 km and up to approximately 109 neas with absolute magnitude h < 30. we present an analysis o... | the near-earth asteroid population from two decades of observations |
context. in the course of a close approach to planets or stars, the morphological and dynamical properties of rubble-pile small bodies can be dramatically modified, and some may catastrophically break up, as in the case of comet shoemaker-levy 9. this phenomenon is of particular interest for the understanding of the ev... | tidal distortion and disruption of rubble-pile bodies revisited. soft-sphere discrete element analyses |
the article is a review of the state of research on physical processes occurring near the surface of airless bodies, in particular, the moon, asteroids, comets, which lead to their erosion, that is, to the modification of superficial and sometimes even deeper layers. external influences on the bodies are considered-mic... | physical processes leading to surface erosion and dust particles dynamics of airless bodies |
like most primitive carbonaceous chondrites, the cm chondrites experienced varying degrees of asteroidal aqueous alteration, which may have overprinted pre-accretionary processing. several aqueous alteration scales for cm chondrites (and other carbonaceous chondrites) have been proposed based on alteration-dependent ch... | noble gases in cm carbonaceous chondrites: effect of parent body aqueous and thermal alteration and cosmic ray exposure ages |
satellite collisions or fragmentations generate a huge number of space debris; over time, the fragments might get dispersed, making it difficult to associate them to the configuration at break-up. in this work, we present a procedure to back-trace the debris, reconnecting them to their original configuration. to this e... | reconnecting groups of space debris to their parent body through proper elements |
unlike the spherical gravitational field of planets and other large solar system bodies, the gravitational field of asteroids is irregular and weak. it is challenging for a planetary rover to obtain sufficient traction forces in this environment. however, this gravitational environment is suitable for legged robots wit... | reinforcement learning-based stable jump control method for asteroid-exploration quadruped robots |
we present an eccentric precessing gas disk model designed to study the variable circumstellar absorption features detected for wd 1145+017, a metal polluted white dwarf with an actively disintegrating asteroid around it. this model, inspired by one recently proposed by cauley et al., calculates explicitly the gas opac... | modeling of the variable circumstellar absorption features of wd 1145+017 |
the defense against near-earth asteroids (neas) using kinetic impact is faced with various challenges, including limited maneuverability of the impactor, inaccurate dynamic models, poor observability of relative navigation, and control execution errors. to address these challenges, an integrated robust navigation and g... | integrated robust navigation and guidance for the kinetic impact of near-earth asteroids based on deep reinforcement learning |
defect interactions can be deduced by a variational method.topological defects play a key role in two-dimensional active nematics, and a transient role in two-dimensional active polar fluids. using a variational method, we study both the transient and long-time behavior of defects in two-dimensional active polar fluids... | defect dynamics in active polar fluids vs. active nematics |
preliminary analyses of asteroid ryugu samples show kinship to aqueously altered ci (ivuna-type) chondrites, suggesting similar origins. we report identification of c-rich, particularly primitive clasts in ryugu samples that contain preserved presolar silicate grains and exceptional abundances of presolar sic and isoto... | abundant presolar grains and primordial organics preserved in carbon-rich exogenous clasts in asteroid ryugu |
diogenites are thought to have originated from asteroid 4 vesta asteroid, and it has been previously shown that they mostly consist of orthopyroxene, chromite, and olivine minerals. in this study, the aioun el atrouss (aat‑1) diogenite was analyzed by vibrational spectroscopic (ft‑ir and micro‑raman), edxrf, and xrd te... | vibrational spectroscopic, crystallographic, and microscopic investigation on the aioun el atrouss diogenite |
hera mission is the european space agency's contribution to the international collaboration with nasa for the planetary defence, i.e. asteroid impact deflection assessment aiming to deflect the trajectory of its target binary asteroid system (65803) didymos. the early characterization phase and the detailed characteriz... | cnn-based image processing algorithm for autonomous optical navigation of hera mission to the binary asteroid didymos |
the origin of the martian moons, phobos and deimos, remains elusive. while the morphology and their cratered surfaces suggest an asteroidal origin1-3, capture has been questioned because of potential dynamical difficulties in achieving the current near-circular, near-equatorial orbits4,5. to circumvent this, in situ fo... | dynamical evidence for phobos and deimos as remnants of a disrupted common progenitor |
the stereophotoclinometry (spc) software suite has been used to generate global digital terrain models (dtms) of many asteroids and moons, and was the primary tool used by the origins, spectral interpretation, resource identification, and security-regolith explorer (osiris-rex) mission to model the shape of asteroid be... | quality assessment of stereophotoclinometry as a shape modeling method using a synthetic asteroid |
the miniaturised asteroid remote geophysical observer (m-argo) is planned to be the first standalone deep-space cubesat mission to rendezvous with and characterise a near-earth asteroid. to this aim, it is essential to assess the attainable set of target asteroids. this work presents the initial results of the mission ... | envelop of reachable asteroids by m-argo cubesat |
line-of-sight (los) navigation is an optical navigation technique that exploits the direction to visible celestial bodies, obtained from an onboard imaging system, to estimate the position and velocity of a spacecraft. the directions are fed to an estimation filter, where they are matched with the actual position of th... | on line-of-sight navigation for deep-space applications: a performance analysis |
a diffractive sail is a solar sail whose exposed surface is covered by an advanced diffractive metamaterial film with engineered optical properties. this study examines the optimal performance of a diffractive solar sail with a sun-facing attitude in a typical orbit-to-orbit heliocentric transfer. a sun-facing attitude... | optimal interplanetary trajectories for sun-facing ideal diffractive sails |
policy gradient (pg) is widely used in reinforcement learning due to its scalability and good performance. in recent years, several variance-reduced pg methods have been proposed with a theoretical guarantee of converging to an approximate first-order stationary point (fosp) with the sample complexity of $o(\epsilon^{-... | efficiently escaping saddle points for non-convex policy optimization |
162173 ryugu, the target of hayabusa2, has a round shape with an equatorial ridge, which is known as a spinning top shape. a strong centrifugal force is a likely contributor to ryugu’s top-shaped features. observations by the optical navigation camera on board hayabusa2 show a unique longitudinal variation in geomorpho... | the western bulge of 162173 ryugu formed as a result of a rotationally driven deformation process |
we analyze a set of 760 475 observations of 333 026 unique main-belt objects obtained by the pan-starrs1 (ps1) survey telescope between 2012 may 20 and 2013 november 9, a period during which ps1 discovered two main-belt comets, p/2012 t1 (panstarrs) and p/2013 r3 (catalina-panstarrs). ps1 comet detection procedures cur... | the main-belt comets: the pan-starrs1 perspective |
the internal structure and strength of small asteroids and large meteoroids is poorly known. observation of bright fireballs in the earth's atmosphere can explore meteoroid structure by studying meteoroid fragmentation during the flight. earlier evaluations showed that the meteoroid's strength is significantly lower th... | two strengths of ordinary chondritic meteoroids as derived from their atmospheric fragmentation modeling |
jbilet winselwan is one of the largest cm carbonaceous chondrites available for study. its light, major, and trace elemental compositions are within the range of other cm chondrites. chondrules are surrounded by dusty rims and set within a matrix of phyllosilicates, oxides, and sulfides. calcium- and aluminum-rich incl... | the alteration history of the jbilet winselwan cm carbonaceous chondrite: an analog for c-type asteroid sample return |
we simulate the formation and evolution of oort clouds around the 200 nearest stars (within ∼16 pc according to the gaia dr2) database. this study is performed by numerically integrating the planets and minor bodies in orbit around the parent star and in the galactic potential. the calculations start 1 gyr ago and cont... | oort cloud ecology. i. extra-solar oort clouds and the origin of asteroidal interlopers |
psr j2129-0429 is a “redback” eclipsing millisecond pulsar binary with an unusually long 15.2 hr orbit. it was discovered by the green bank telescope in a targeted search of unidentified fermi gamma-ray sources. the pulsar companion is optically bright (mean mr = 16.6 mag), allowing us to construct the longest baseline... | properties and evolution of the redback millisecond pulsar binary psr j2129-0429 |
atmospheric heavy elements have been observed in more than a quarter of white dwarfs (wds) at different cooling ages, indicating ongoing accretion of asteroidal material, whilst only a few per cent of the wds possess a dust disc, and all these wds are accreting metals. here, assuming that a rubble-pile asteroid is scat... | accretion of tidally disrupted asteroids on to white dwarfs: direct accretion versus disc processing |
polluted white dwarfs serve as astrophysical mass spectrometers - their photospheric abundances are used to infer the composition of planetary objects that accrete onto them. we show that due to asymmetries in the accretion process, the composition of the material falling onto a star may vary with time during the accre... | asynchronous accretion can mimic diverse white dwarf pollutants i: core and mantle fragments |
exoplanets orbiting in the habitable zone around m dwarf stars have been prime targets in the search for life due to the long lifetimes of the host star, the prominence of such stars in the galaxy, and the apparent excess of terrestrial planets found around m dwarfs. however, the heightened stellar activity of m dwarfs... | life on exoplanets in the habitable zone of m dwarfs? |
the double asteroid redirection test (dart) is a nasa mission intended to crash a projectile on dimorphos, the secondary component of the binary (65803) didymos system, to study its orbit deflection. as a consequence of the impact, a dust cloud will be be ejected from the body, potentially forming a transient coma- or ... | ground-based observability of dimorphos dart impact ejecta: photometric predictions |
we have monitored the didymos-dimorphos binary asteroid in spectropolarimetric mode in the optical range before and after the dart impact. the ultimate goal was to obtain constraints on the characteristics of the ejected dust for modeling purposes. before impact, didymos exhibited a linear polarization rapidly increasi... | optical spectropolarimetry of binary asteroid didymos-dimorphos before and after the dart impact |
craters formed by the impact of agglomerated materials are commonly observed in nature, such as asteroids colliding with planets and moons. in this paper, we investigate how the projectile spin and cohesion lead to different crater shapes. for that, we carried out discrete element method computations of spinning granul... | impact craters formed by spinning granular projectiles |
studies of material returned from cb asteroid ryugu have revealed considerable mineralogical and chemical heterogeneity, stemming primarily from brecciation and aqueous alteration. isotopic anomalies could have also been affected by delivery of exogenous clasts and aqueous mobilization of soluble elements. here, we sho... | water circulation in ryugu asteroid affected the distribution of nucleosynthetic isotope anomalies in returned sample |
macroscopic dark matter is almost unconstrained over a wide "asteroidlike" mass range, where it could scatter on baryonic matter with geometric cross section. we show that when such an object travels through a star, it produces shock waves that reach the stellar surface, leading to a distinctive transient optical, uv, ... | stellar shocks from dark matter asteroid impacts |
dark compact objects ("clumps") transiting the solar system exert accelerations on the test masses (tm) in a gravitational-wave (gw) detector. we reexamine the detectability of these clump transits in a variety of current and future gw detectors, operating over a broad range of frequencies. tm accelerations induced by ... | searching for dark clumps with gravitational-wave detectors |
we examine the history of the loss and replenishment of the martian atmosphere using elemental and isotopic compositions of nitrogen and noble gases. the evolution of the atmosphere is calculated by taking into consideration various processes: impact erosion and replenishment by asteroids and comets, atmospheric escape... | a lower limit of atmospheric pressure on early mars inferred from nitrogen and argon isotopic compositions |
we present a series of papers dedicated to modelling the accretion and differentiation of rocky planets that form by pebble accretion within the lifetime of the protoplanetary disc. in this first paper, we focus on how the accreted ice determines the distribution of iron between the mantle (oxidized feo and feo1.5) and... | anatomy of rocky planets formed by rapid pebble accretion. i. how icy pebbles determine the core fraction and feo contents |
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