abstract stringlengths 3 192k | title stringlengths 4 857 |
|---|---|
we consider the off-lattice two-dimensional q-state active clock model (acm) as a natural discretization of the vicsek model (vm) describing flocking. the acm consists of particles able to move in the plane in a discrete set of q equidistant angular directions, as in the active potts model (apm), with an alignment inte... | polar flocks with discretized directions: the active clock model approaching the vicsek model |
asteroid (101955) bennu, a near-earth object with a primitive carbonaceous chondrite-like composition, was observed by the origins, spectral interpretation, resource identification, and security-regolith explorer (osiris-rex) spacecraft to undergo multiple particle ejection events near perihelion between december 2018 ... | meteoroid impacts as a source of bennu's particle ejection events |
the solar system currently possesses two remnant debris disks leftover from the planetary formation era in the form of the asteroid belt and the edgeworth-kuiper belt (ekb). similar to other stellar systems, these debris disks continually generate submillimeter-sized dust grains through processes such as mutual collisi... | constraining the solar system's debris disk with in situ new horizons measurements from the edgeworth-kuiper belt |
we have analyzed the orbits and ablation characteristics in the atmosphere of 59 earth-impacting fireballs, produced by meteoroids 1 m in diameter or larger, described here as meter-scale. using heights at peak luminosity as a proxy for strength, we determine that there is roughly an order of magnitude spread in streng... | orbital and physical characteristics of meter-scale impactors from airburst observations |
the discovery of over 50 planets around evolved stars and more than 35 debris discs orbiting white dwarfs highlight the increasing need to understand small body evolution around both early and asymptotic giant branch (gb) stars. pebbles and asteroids are susceptible to strong accelerations from the intense luminosity a... | the orbital evolution of asteroids, pebbles and planets from giant branch stellar radiation and winds |
from near-earth asteroids to superluminous supernovae and gravitational wave counterparts, the zwicky transient facility will soon scan for transient phenomena, explain eric bellm and shrinivas kulkarni. | the unblinking eye on the sky |
the earth is impacted by 35-40 metre-scale objects every year. these meteoroids are the low-mass end of impactors that can do damage on the ground. despite this they are very poorly surveyed and characterized, too infrequent for ground-based fireball observation efforts, and too small to be efficiently detected by neo ... | observation of metre-scale impactors by the desert fireball network |
we present the results of melting experiments on a suite of carbonaceous and ordinary chondritic compositions (cv, cm, ci, h and ll) performed at low pressure (0.1-13.1 mpa) and over a range of oxygen fugacity (log fo2 - (log fo2)iw = -2.5 to -1 and +0.8, iw being the iron-wustite buffer). these experiments constrain t... | widespread production of silica- and alkali-rich melts at the onset of planetesimal melting |
pulsar-timing analyses are sensitive to errors in the solar-system ephemerides (sses) that timing models utilize to estimate the location of the solar-system barycentre, the quasi-inertial reference frame to which all recorded pulse times-of-arrival are referred. any error in the sse will affect all pulsars, therefore ... | studying the solar system with the international pulsar timing array |
we report 491 new near-infrared spectroscopic measurements of 420 near-earth objects (neos) collected on the nasa infrared telescope facility as part of the mit-hawaii neo spectroscopic survey. these measurements were combined with previously published data from binzel et al. and bias-corrected to derive the intrinsic ... | the debiased compositional distribution of mithneos: global match between the near-earth and main-belt asteroid populations, and excess of d-type near-earth objects |
in this work we identify spectral similarities between asteroids and meteorites. using spectral features such as absorption bands and spectral curvature, we identify spectral matches between 500 asteroid spectra and over 1,000 samples of relab meteorite spectra over visible plus near-infrared wavelengths (0.45- 2 . 5 μ... | connecting asteroids and meteorites with visible and near-infrared spectroscopy |
we have presented in this communication a new solving procedure for the dynamics of non-rigid asteroid rotation, considering the final spin state of rotation for a small celestial body (asteroid). the last condition means the ultimate absence of the applied external torques (including short-term effect from torques dur... | on the dynamics of non-rigid asteroid rotation |
in growing active matter systems, a large collection of engineered or living autonomous units metabolize free energy and create order at different length scales as they proliferate and migrate collectively. one such example is bacterial biofilms, surface-attached aggregates of bacterial cells embedded in an extracellul... | mechanical forces drive a reorientation cascade leading to biofilm self-patterning |
the solar power sail is an original japanese concept in which electric power is generated by thin-film solar cells attached on the solar sail membrane. japan aerospace exploration agency (jaxa) successfully demonstrated the world's first solar power sail technology through ikaros (interplanetary kite-craft accelerated ... | solar power sail mission of okeanos |
osiris-rex is the first nasa mission to return a sample of an asteroid to earth. navigation and flight dynamics for the mission to acquire and return a sample of asteroid 101955 bennu establish many firsts for space exploration. these include relatively small orbital maneuvers that are precise to ∼1 mm/s, close-up oper... | osiris-rex flight dynamics and navigation design |
we present archival observations of main-belt asteroid (248370) 2005 qn173 (also designated 433p) that demonstrate this recently discovered active asteroid (a body with a dynamically asteroidal orbit displaying a tail or coma) has had at least one additional apparition of activity near perihelion during a prior orbit. ... | recurrent activity from active asteroid (248370) 2005 qn173: a main-belt comet |
in marine and freshwater oxygen-deficient zones, the remineralization of sinking organic matter from the photic zone is central to driving nitrogen loss. deep blooms of photosynthetic bacteria, which form the suboxic/anoxic chlorophyll maximum (acm), widespread in aquatic ecosystems, may also contribute to the local in... | anoxic chlorophyll maximum enhances local organic matter remineralization and nitrogen loss in lake tanganyika |
potentially hazardous asteroids and comets have hit earth throughout its history, with catastrophic consequences in the case of the chicxulub impact. here we reexamine one of the mechanisms that allow an impact to have a global effect—the release of climate-active gases from sedimentary rocks. we use the sova hydrocode... | quantifying the release of climate-active gases by large meteorite impacts with a case study of chicxulub |
magnetite (fe3+(fe2+fe3+)2o4) is ubiquitous in earth and planetary materials, forming in igneous, metamorphic, and sedimentary settings, sometimes influenced by microbiology. magnetite can be used to study many and varied planetary processes, such as the oxidation state of magmas, paleomagnetism, water-rock interaction... | spectral reflectance properties of magnetites: implications for remote sensing |
the source of water (h2o) and hydroxyl radicals (oh), identified on the lunar surface, represents a fundamental, unsolved puzzle. the interaction of solar-wind protons with silicates and oxides has been proposed as a key mechanism, but laboratory experiments yield conflicting results that suggest that proton implantati... | untangling the formation and liberation of water in the lunar regolith |
the delivery of water to the inner solar system, including earth, is still a debated topic. a preferential role for hydrated asteroids in this process is supported by isotopic measurements. carbonaceous chondrite (cc) meteorites represent our main source of information about these volatile-rich asteroids. however, the ... | oxygen isotope evidence from ryugu samples for early water delivery to earth by ci chondrites |
this work explores the target selection and trajectory design of the mission candidate for isas/jaxa's small science satellite series, destiny plus or destiny+. this mission combines unique aspects of the latest satellite technology and exploration of transition bodies to fill a technical and scientific gap in the japa... | destiny+ trajectory design to (3200) phaethon |
asteroid (162173) ryugu is the target object of hayabusa2, an asteroid exploration and sample return mission led by japan aerospace exploration agency (jaxa). ground-based observations indicate that ryugu is a c-type near-earth asteroid with a diameter of less than 1 km, but the knowledge of its detailed properties is ... | asteroid ryugu before the hayabusa2 encounter |
in the last decades, the necessity to process massive amounts of textual data fueled the development of compressed text indexes: data structures efficiently answering queries on a given text while occupying space proportional to the compressed representation of the text. a widespread phenomenon in compressed indexing i... | collapsing the hierarchy of compressed data structures: suffix arrays in optimal compressed space |
a class of graphs $\mathscr{c}$ is monadically stable if for any unary expansion $\widehat{\mathscr{c}}$ of $\mathscr{c}$, one cannot interpret, in first-order logic, arbitrarily long linear orders in graphs from $\widehat{\mathscr{c}}$. it is known that nowhere dense graph classes are monadically stable; these encompa... | flipper games for monadically stable graph classes |
(10) hygiea is the fourth largest main belt asteroid and the only known asteroid whose surface composition appears similar to that of the dwarf planet (1) ceres1,2, suggesting a similar origin for these two objects. hygiea suffered a giant impact more than 2 gyr ago3 that is at the origin of one of the largest asteroid... | a basin-free spherical shape as an outcome of a giant impact on asteroid hygiea |
many isolated white dwarfs (wds) show spectral evidence of atmospheric metal pollution. since heavy-element sedimentation timescales are short, this most likely indicates ongoing accretion. accreted metals encounter a variety of mixing processes at the wd surface: convection, gravitational sedimentation, overshoot, and... | polluted white dwarfs: mixing regions and diffusion timescales |
we address the expressions for the rates of the keplerian orbital elements within a two-body problem perturbed by the tides in both partners. formulae for these rates appeared in the literature in various forms, at times with errors. we reconsider, from scratch, the derivation of these rates and arrive at the lagrange-... | tidal evolution of the keplerian elements |
the near-earth objects (neos) (3200) phaethon and (155140) 2005 ud are thought to share a common origin, with the former exhibiting dust activity at perihelion that is thought to directly supply the geminid meteor stream. both of these objects currently have very small perihelion distances (0 . 140 au and 0 . 163 au fo... | dynamical evolution and thermal history of asteroids (3200) phaethon and (155140) 2005 ud |
this paper shows that $k_t$-minor-free (and $k_{s, t}$-minor-free) graphs $g$ are subgraphs of products of a tree-like graph $h$ (of bounded treewidth) and a complete graph $k_m$. our results include optimal bounds on the treewidth of $h$ and optimal bounds (to within a constant factor) on $m$ in terms of the number of... | product structure of graphs with an excluded minor |
wd 1145+017 was observed from 2015 november to 2016 july, for the purpose of characterizing transit behaviour of the white dwarf by dust clouds thought to be produced by fragments of an asteroid in close orbit with the star. fortuitously, most of these observations were carried out during a time when the overall 'dip' ... | wd 1145+017 photometric observations during eight months of high activity |
given the current transformative potential of research that sits at the intersection of deep learning (dl) and software engineering (se), an nsf-sponsored community workshop was conducted in co-location with the 34th ieee/acm international conference on automated software engineering (ase'19) in san diego, california. ... | deep learning & software engineering: state of research and future directions |
sitian is an ambitious ground-based all-sky optical monitoring project, developed by the chinese academy of sciences. the concept is an integrated network of dozens of 1-m-class telescopes deployed partly in china and partly at various other sites around the world. the main science goals are the detection, identificati... | the sitian project |
a significant fraction of white dwarfs show metal lines indicative of pollution with planetary material but the accretion process remains poorly understood. the main aim of this paper is to produce a road-map illustrating several potential routes for white dwarf pollution and to link these paths to observational outcom... | a road-map to white dwarf pollution: tidal disruption, eccentric grind-down, and dust accretion |
nasa's double asteroid redirection test (dart) mission will impact its target asteroid, dimorphos, at an oblique angle that will not be known prior to the impact. we computed isale-3d simulations of dart-like impacts on asteroid surfaces at different impact angles and found that the vertical momentum transfer efficienc... | ejecta distribution and momentum transfer from oblique impacts on asteroid surfaces |
asteroid interiors play a key role in our understanding of asteroid formation and evolution. as no direct interior probing has been done yet, characterisation of asteroids' interiors relies on interpretations of external properties. here we show, by numerical simulations, that the top-shaped rubble-pile asteroid (10195... | inferring interiors and structural history of top-shaped asteroids from external properties of asteroid (101955) bennu |
thermophysical models allow for improved constraints on the physical and thermal surface properties of asteroids beyond what can be inferred from more simple thermal modeling, provided that a sufficient number of observations is available. we present thermophysical modeling results of observations from the near-earth o... | thermophysical modeling of neowise observations of destiny+ targets phaethon and 2005 ud |
in this paper we update, extend, and improve upon the recent paper on near-earth asteroid (nea) population by harris and d'abramo (2015). we update the population estimate taking into account discoveries to august 3, 2020. shortly after the previous paper was published, we identified a problem in our previous studies d... | the population of near-earth asteroids revisited and updated |
ancient layers of impact spherules provide a record of earth's early bombardment history. here, we compare different bombardment histories to the spherule layer record and show that 3.2-3.5 ga the flux of large impactors (10-100 km in diameter) was likely 20-40 times higher than today. the e-belt model of early solar s... | spherule layers, crater scaling laws, and the population of ancient terrestrial impactors |
we present imaging and spectroscopic observations of 6478 gault, a ∼6 km diameter inner main-belt asteroid currently exhibiting strong, comet-like characteristics. three distinct tails indicate that ultra-slow dust (ejection speed 0.15 ± 0.05 m s-1) was emitted from gault in separate episodes beginning ut 2018 october ... | episodically active asteroid 6478 gault |
the origin and evolution of solar system bodies, including water on the earth, have been discussed based on the assumption that the relevant ingredients were simply silicates and ices. however, large amounts of organic matter have been found in cometary and interplanetary dust, which are recognized as remnants of inter... | precometary organic matter: a hidden reservoir of water inside the snow line |
the analysis of the optimal control law that steers a solar sail-based spacecraft from a given initial condition toward a final target state is typically carried out using either indirect or direct approaches. both these methods are usually time-consuming and require good initial guesses of costates or state vector. th... | shape-based approach for solar sail trajectory optimization |
anhydrous pyroxene-rich interplanetary dust particles (idps) have been proposed as surface analogs for about two-thirds of all c-complex asteroids. however, this suggestion appears to be inconsistent with the presence of hydrated silicates on the surfaces of some of these asteroids, including ceres. here, we report the... | different origins or different evolutions? decoding the spectral diversity among c-type asteroids |
’oumuamua was discovered passing through our solar system on a hyperbolic orbit. it presents an apparent contradiction, with colors similar to those of volatile-rich solar system bodies but with no visible outgassing or activity during its close approach to the sun. here, we show that this contradiction can be explaine... | interstellar object ’oumuamua as an extinct fragment of an ejected cometary planetesimal |
the most heavily polluted white dwarfs often show excess infrared radiation from circumstellar dust disks, which are modeled as a result of tidal disruption of extrasolar minor planets. interaction of dust, gas, and disintegrating objects can all contribute to the dynamical evolution of these dust disks. here, we repor... | infrared variability of two dusty white dwarfs |
to investigate the origin of fine-grained rims around chondrules (fgrs), we compared presolar grain abundances, elemental compositions and mineralogies in fine-grained interstitial matrix material and individual fgrs in the primitive co3.0 chondrites allan hills a77307, lapaz icefield 031117 and dominion range 08006. t... | presolar silicates in the matrix and fine-grained rims around chondrules in primitive co3.0 chondrites: evidence for pre-accretionary aqueous alteration of the rims in the solar nebula |
over the past 3 decades, there has been an exponential increase in work done in the newly emerging field of matter at extreme states of deformation and compression. this accelerating progress is due to the confluence of new experimental facilities, experimental techniques, theory, and simulations. regimes of science hi... | from microjoules to megajoules and kilobars to gigabars: probing matter at extreme states of deformation |
an interplanetary trajectory optimization of the multi-asteroid rendezvous is investigated for a solar sail-based spacecraft. the optimal control problem is formulated using the calculus of variations and pontryagin's maximum principle and the first order necessary conditions for optimality of the problem are derived. ... | solar sail trajectory optimization of multi-asteroid rendezvous mission |
in two recent papers published in mnras, namouni and morais claimed evidence for the interstellar origin of some small solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined centaurs. here, we discuss the flaws of those papers that invalidate the ... | no evidence for interstellar planetesimals trapped in the solar system |
during the planet formation process, billions of comets are created and ejected into interstellar space. the detection and characterization of such interstellar comets (ics) (also known as extra-solar planetesimals or extra-solar comets) would give us in situ information about the efficiency and properties of planet fo... | realistic detectability of close interstellar comets |
carbonaceous asteroids represent the principal source of water in the inner solar system and might correspond to the main contributors for the delivery of water to earth. hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of... | a dual origin for water in carbonaceous asteroids revealed by cm chondrites |
the mission accessible near-earth object survey (manos) aims to observe and characterize small (mean absolute magnitude h ∼ 25 mag) near-earth objects (neos) that are accessible by spacecraft (mean δv ∼ 5.7 km s-1) and that make close approaches with the earth (mean minimum orbital intersection distance moid ∼ 0.03 au)... | visible spectroscopy from the mission accessible near-earth object survey (manos): taxonomic dependence on asteroid size |
the nasa double asteroid redirection test (dart) mission is a planetary defense-driven test of a kinetic impactor on dimorphos, the satellite of the binary asteroid 65803 didymos. dart will intercept dimorphos at a relative speed of ∼ 6 . 5km s-1 , perturbing dimorphos's orbital velocity and changing the binary orbital... | the excited spin state of dimorphos resulting from the dart impact |
dujmović, joret, micek, morin, ueckerdt and wood [j. acm 2020] proved that for every planar graph $g$ there is a graph $h$ with treewidth at most 8 and a path $p$ such that $g\subseteq h\boxtimes p$. we improve this result by replacing "treewidth at most 8" by "simple treewidth at most 6". | an improved planar graph product structure theorem |
this paper summarizes a commercial asteroid mining architecture synthesized by the senior space design class at the university of washington in winter/spring quarters of 2013. the main author was the instructor for that class. these results use design-to-cost development methods and focused infrastructure advancements ... | defining a successful commercial asteroid mining program |
japan's second asteroid explorer hayabusa2 was successfully launched on dec 3, 2014, to return a sample from asteroid 162173 ryugu by 2020. four xenon ion thrusters based on electron cyclotron resonance discharge propelled the spacecraft for 547 h during its first year in space. hayabusa2 completed an earth gravity ass... | in-flight operation of the hayabusa2 ion engine system on its way to rendezvous with asteroid 162173 ryugu |
the geological map encapsulates basic information that can be crucial in a multitude of fields such as landslide risk assessment, engineering projects, as well as petroleum and mineral resources studies. in addition, it is difficult, expensive and time-consuming to achieve it in complex and inaccessible lands. however,... | using remote sensing data for geological mapping in semi-arid environment: a machine learning approach |
this paper presents a study, through the use of a ssdem simulation code, of the possible disruption patterns and mechanisms of self-gravitating aggregates that are spun-up to the point of disruption. we do this survey by systematically changing the angle of friction and tensile stress of the aggregates. it is observed ... | disruption patterns of rotating self-gravitating aggregates: a survey on angle of friction and tensile strength |
context. the populations of small bodies of the solar system (asteroids, comets, and kuiper belt objects) are used to constrain the origin and evolution of the solar system. their orbital distribution and composition distribution are both required to track the dynamical pathway from their formation regions to their cur... | multifilter photometry of solar system objects from the skymapper southern survey |
over one-quarter of white dwarfs contain observable metallic debris from the break-up of exo-asteroids. understanding the physical and orbital history of this debris would enable us to self-consistently link planetary system formation and fate. one major debris reservoir is generated by yorp-induced rotational fission ... | post-main-sequence debris from rotation-induced yorp break-up of small bodies - ii. multiple fissions, internal strengths, and binary production |
in this paper, four off-earth mining scenarios for water extraction have been designed to supply a h2/lox propellant market in low earth orbit. a non-financial measure for determining feasibility has been devised for the analysis based on the opportunity cost as opposed to the net present value. the first scenario for ... | technical evaluation of off-earth ice mining scenarios through an opportunity cost approach |
almahata sitta (ahs), an anomalous polymict ureilite, is the first meteorite observed to originate from a spectrally classified asteroid (2008 tc3). however, correlating properties of the meteorite with those of the asteroid is not straightforward because the ahs stones are diverse types. of those studied prior to this... | the first samples from almahata sitta showing contacts between ureilitic and chondritic lithologies: implications for the structure and composition of asteroid 2008 tc3 |
the otherwise homogeneous surface of ceres is dotted with hundreds of anomalously bright, predominantly carbonate-bearing areas, termed "faculae," with bond albedos ranging from ∼0.02 to >0.5. here, we classify and map faculae globally to characterize their geological setting, assess potential mechanisms for their f... | the formation and evolution of bright spots on ceres |
photosynthesis (gross primary production, gpp) and evapotranspiration (et) are ecosystem processes with global significance for climate, the global carbon and hydrological cycles and a range of ecosystem services. the mechanisms governing these processes are complex but well understood. there is strong coupling between... | description and validation of an intermediate complexity model for ecosystem photosynthesis and evapotranspiration: acm-gpp-etv1 |
of the potential volatile sources for the terrestrial planets, the ci and cm carbonaceous chondrites are closest to the planets' bulk h and n isotopic compositions. for the earth, the addition of approximately 2-4 wt% of ci/cm material to a volatile-depleted proto-earth can explain the abundances of many of the most vo... | the origin of inner solar system water |
the zag meteorite which is a thermally-metamorphosed h ordinary chondrite contains a primitive xenolithic clast that was accreted to the parent asteroid after metamorphism. the cm-sized clast contains abundant large organic grains or aggregates up to 20 μm in phyllosilicate-rich matrix. here we report organic and isoto... | a novel organic-rich meteoritic clast from the outer solar system |
asteroids are fascinating worlds. considered the building blocks of our planets, many of the authors of this book have devoted their scientific careers to exploring them with the tools of our trade: ground- and spacebased observations, in situ space missions, and studies that run the gamut from theoretical modeling eff... | asteroids iv |
context. the sample of solar system objects has dramatically increased over the last decade. the number of measured properties (e.g., diameter, taxonomy, rotation period, thermal inertia, etc.) has expanded even more quickly. however, this wealth of information is spread over a myriad of studies, with different designa... | ssodnet: solar system open database network |
the migration history of jupiter in the sun's natal disk remains poorly constrained. here we consider how jupiter's migration affects small-body reservoirs and how this constrains its original orbital distance from the sun. we study the implications of large-scale and inward radial migration of jupiter for the inner so... | implications of jupiter inward gas-driven migration for the inner solar system |
we report on the mass-independent cr isotope compositions of 11 main group ureilites and an ureilitic trachyandesite (alm-a). the 54cr/52cr ratios for main group ureilites vary from -1.06 ± 0.04 to -0.78 ± 0.05 and averaged at -0.91 ± 0.15 (2sd, n = 18) including the data from literature. we argue that this variation r... | chromium isotopic constraints on the origin of the ureilite parent body |
both physical and dynamical properties must be considered to constrain the origins of the dynamically excited distant solar system populations. we present high-precision (g-r) colors for 25 small (h r > 5) dynamically excited trans-neptunian objects (tnos) and centaurs acquired as part of the colours of the outer so... | col-ossos: color and inclination are correlated throughout the kuiper belt |
we present archival observations demonstrating that main belt asteroid (6478) gault has an extensive history of comet-like activity. outbursts have taken place during multiple epochs since 2013 and at distances extending as far as 2.68 au, nearly aphelion. (6478) gault is a member of the predominately s-type (i.e., vol... | six years of sustained activity in (6478) gault |
climate simulations that consider injection into the atmosphere of 15,000 tg of soot, the amount estimated to be present at the cretaceous-paleogene boundary, produce what might have been one of the largest episodes of transient climate change in earth history. the observed soot is believed to originate from global wil... | on transient climate change at the cretaceous-paleogene boundary due to atmospheric soot injections |
leading up to the 2015 iau general assembly, the international astronomical union's working list of meteor showers included 486 unconfirmed showers, showers that are not certain to exist. if confirmed, each shower would provide a record of past comet or asteroid activity. now, we report that 41 of these are detected in... | cams confirmation of previously reported meteor showers |
we have observed c/2014 s3 (panstarrs), a recently discovered object on a cometary orbit coming from the oort cloud that is physically similar to an inner main belt rocky s-type asteroid. recent dynamical models successfully reproduce the key characteristics of our current solar system; some of these models require sig... | inner solar system material discovered in the oort cloud |
spectroscopy in planetary science often provides the only information regarding the compositional and mineralogical make up of planetary surfaces. the methods employed when curve fitting and modelling spectra can be confusing and difficult to visualize and comprehend. researchers who are new to working with spectra may... | fitting the curve in excel®: systematic curve fitting of laboratory and remotely sensed planetary spectra |
this paper presents a study, through the use of a soft-sphere discrete element method, of possible deformation and disruption patterns of spinning, self-gravitating spherical aggregates with cores of variable strengths. we present this study as a complement to our previous study about aggregates with strong cores that ... | rotational evolution of self-gravitating aggregates with cores of variable strength |
the moon is the only planetary body other than the earth for which samples have been collected in situ by humans and robotic missions and returned to earth. scientific investigations of the first lunar samples returned by the apollo 11 astronauts 50 years ago transformed the way we think most planetary bodies form and ... | constraining the evolutionary history of the moon and the inner solar system: a case for new returned lunar samples |
geochemical models describing the behaviour of niobium during earth’s growth rely on the general paradigm that niobium was delivered by earth’s asteroidal building blocks at chondritic abundances. this paradigm is based on the observation that niobium is traditionally regarded as a refractory and strongly lithophile el... | silicate earth’s missing niobium may have been sequestered into asteroidal cores |
a fundamental aspect of the three-body problem is its stability. most stability studies have focused on the co-planar three-body problem, deriving analytic criteria for the dynamical stability of such pro/retrograde systems. numerical studies of inclined systems phenomenologically mapped their stability regions, but ne... | generalized hill-stability criteria for hierarchical three-body systems at arbitrary inclinations |
small bodies such as the near-earth asteroid bennu drift in their orbit due to thermal radiation forces (the yarkovsky effect). ground-based observations have indicated a nonzero probability of bennu impacting earth, depending on how its orbit evolves. thus, among the goals of the osiris-rex (origins, spectral interpre... | ephemeris and hazard assessment for near-earth asteroid (101955) bennu based on osiris-rex data |
we report radar observations of apophis obtained during the 2012-2013 apparition. we observed apophis on fourteen days at goldstone (8560 mhz, 3.5 cm) and on five days at arecibo (2380 mhz, 12.3 cm) between 2012 december 21 to 2013 march 16. closest approach occurred on january 9 at a distance of 0.097 au. we obtained ... | goldstone and arecibo radar observations of (99942) apophis in 2012-2013 |
ceres, a dwarf planet located in the main asteroid belt, has a low bulk density1, and models predict that a substantial amount of water ice is present in its mantle and outer shell2-4. the herschel telescope and the dawn spacecraft5 have observed the release of water vapour from ceres6,7, and exposed water ice has been... | surface water-ice deposits in the northern shadowed regions of ceres |
artificial manipulation of acoustic waves is a highly active research area, in which negative reflection is an exotic phenomenon. emerging acoustic coding metasurfaces (acms) show great power in controlling acoustic waves. here, we propose an acm, where the state "0" or "1" is achieved by pushing up or pressing down a ... | tunable perfect negative reflection based on an acoustic coding metasurface |
context. pebble accretion is a newly discovered mechanism to quickly grow the cores of planets. in pebble accretion, gravity and gas drag conspire to yield large collisional cross sections for small particles in protoplanetary disks. however, before pebble accretion commences, aerodynamic deflection may act to prevent ... | on the growth of pebble-accreting planetesimals |
context. asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. these efforts already provided deep insight into physical properties of main-belt asteroids or large collisional families. going into finer detail (e.g., smaller collisi... | new and updated convex shape models of asteroids based on optical data from a large collaboration network |
we conducted a two-night photometric survey of small kuiper belt objects (kbos) near opposition using the wide-field hyper suprime-cam instrument on the 8.2 m subaru telescope. the survey covered about 90 deg2 of sky, with each field imaged in the g and i bands. we detected 356 kbos, ranging in absolute magnitude from ... | the bimodal color distribution of small kuiper belt objects |
solar system bodies with surface and subsurface volatiles will show observational evidence of activity when they reach a temperature where those volatiles change from solid to gas and are released. this is most frequently seen in comets, where activity is driven by the sublimation of water, carbon dioxide, or carbon mo... | volatility of sodium in carbonaceous chondrites at temperatures consistent with low-perihelion asteroids |
many asteroids are rubble piles with irregular shapes. while the irregular shapes of large asteroids may be attributed to collisional events, those of small asteroids may result from not only impact events but also rotationally induced failure, a long-term consequence of small torques caused by, for example, solar radi... | rotationally induced failure of irregularly shaped asteroids |
the appearance of interstellar objects (isos) in the solar system-and specifically the arrival of 1i/'oumuamua-points to a significant number density of free-floating bodies in the solar neighborhood. we review the details of 'oumuamua's pre-encounter galactic orbit, which intersected the solar system at very nearly it... | evidence suggesting that 'oumuamua is the30 myr old product of a molecular cloud |
two meteorite pieces have been recovered in italy, near the town of cavezzo (modena), on 2020 january 4th. the associated fireball was observed on the evening of new year's day 2020 by eight all-sky cameras of the prisma fireball network, a partner of fripon. the computed trajectory had an inclination angle of approxim... | cavezzo, the first italian meteorite recovered by the prisma fireball network. orbit, trajectory, and strewn-field |
the relative motion about 4179 toutatis is studied in order to investigate the feasibility of formation flying as an alternative concept for future asteroid exploration missions. in particular, the existence of quasi-frozen orbits about slowly rotating bodies allows us to compute families of periodic orbits in the body... | bounded relative orbits about asteroids for formation flying and applications |
polluted white dwarfs that have accreted planetary material provide a unique opportunity to probe the geology of exoplanetary systems. however, the nature of the bodies that pollute white dwarfs is not well understood: are they small asteroids, minor planets, or even terrestrial planets? we present a novel method to in... | planets or asteroids? a geochemical method to constrain the masses of white dwarf pollutants |
a cluster of gridded microwave discharge ion thrusters μ10 contributed to the success of the deep space exploration missions of the japanese asteroid explorers hayabusa and hayabusa2. to meet the demands of the next mission destiny+, the maximum ion beam current was increased to 200 ma from the 170 ma used in hayabusa2... | plasma hysteresis caused by high-voltage breakdown in gridded microwave discharge ion thruster μ10 |
the inner solar system’s biggest and most recent known collision was the moon-forming giant impact between a large protoplanet and proto-earth. not only did it create a disk near earth that formed the moon, it also ejected several percent of an earth mass out of the earth-moon system. here, we argue that numerous kilom... | dating the moon-forming impact event with asteroidal meteorites |
exoplanet discoveries since the mid-1990's have revealed an astounding diversity of planetary systems. studying these systems is essential to understanding planetary formation processes, as well as the development of life in the universe. unfortunately, humanity can only observe limited aspects of exoplanetary systems ... | bridge to the stars: a mission concept to an interstellar object |
tropical forests act as a major sink of atmospheric carbon dioxide, and store large amounts of carbon in biomass. india is a tropical country with regions of dense vegetation and high biodiversity. however due to the paucity of observations, the carbon sequestration potential of these forests could not be assessed in d... | estimating gross primary productivity of a tropical forest ecosystem over north-east india using lai and meteorological variables |
we observed the near-earth asteroid (101955) bennu from the ground in 1999 and 2005, and with the hubble space telescope (hst) in 2012, to constrain its rotation rate. the data reveal an acceleration of 2.64 ± 1.05 × 10-6 deg/day2, which could be due to a change in the moment of inertia of bennu or to spin up from the ... | detection of rotational acceleration of bennu using hst light curve observations |
the main asteroid belt (mb) is low in mass but dynamically excited. here we propose a new mechanism to excite the mb during the giant planet (the “nice model”) instability, which is expected to feature repeated close encounters between jupiter and one or more ice giants (“jumping jupiter” or jj). we show that, when jup... | excitation of a primordial cold asteroid belt as an outcome of planetary instability |
boulders are ubiquitously found on the surfaces of small rocky bodies in the inner solar system and their spatial and size distributions give insight into the geological evolution and collisional history of the parent bodies. using images acquired by the chang’e-2 spacecraft, more than 200 boulders have been identified... | boulders on asteroid toutatis as observed by chang’e-2 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.