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Marco Delbo - One of the best experts on this subject based on the ideXlab platform.
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Exogenic basalt on Asteroid (101955) Bennu
Nature Astronomy, 2020Co-Authors: D. Dellagiustina, W F Bottke, Marco Delbo, Chrysa Avdellidou, Hana H. Kaplan, Amy A. Simon, Ronald-l Ballouz, D. Golish, Walsh K., H. CampinsAbstract:When rubble-pile Asteroid 2008 TC3 impacted Earth on October 7, 2008, the recovered rock fragments indicated that such Asteroids can contain exogenic material [1,2]. However, spacecraft missions to date have only observed exogenous contamination on large, monolithic Asteroids that are impervious to collisional disruption [3, 4]. Here we report the presence of meter-scale exogenic boulders on the surface of near-Earth Asteroid (101955) Bennu—the 0.5-km, rubble-pile target of the OSIRIS-REx mission [5] which has been spectroscopically linked to the CM carbonaceous chondrite meteorites [6]. Hyperspectral data indicate that the exogenic boulders have the same distinctive pyroxene composition as the howardite–eucrite–diogenite (HED) meteorites that come from (4) Vesta, a 525-km- diameter Asteroid that has undergone differentiation and extensive igneous processing [7, 8, 9]. Delivery scenarios include the infall of Vesta fragments directly onto Bennu or indirectly onto Bennu’s parent body, where the latter’s disruption created Bennu from a mixture of endogenous and exogenic debris. Our findings demonstrate that rubble-pile Asteroids can preserve evidence of inter-Asteroid mixing that took place at macroscopic scales well after planetesimal formation ended. Accordingly, the presence of HED-like material on the surface of Bennu provides previously unrecognized constraints on the collisional and dynamical evolution of the inner main belt.
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Ancient and primordial collisional families as the main sources of X-type Asteroids of the inner main belt
Astronomy and Astrophysics - A&A, 2019Co-Authors: Marco Delbo, Chrysa Avdellidou, Alessandro MorbidelliAbstract:Aims. The near-Earth Asteroid population suggests the existence of an inner main belt source of Asteroids that belongs to the spectroscopic X complex and has moderate albedos. The identification of such a source has been lacking so far. We argue that the most probable source is one or more collisional Asteroid families that have escaped discovery up to now. Methods. We apply a novel method to search for Asteroid families in the inner main-belt population of Asteroids belonging to the X complex with moderate albedo. Instead of searching for Asteroid clusters in orbital element space, which could be severely dispersed when older than some billions of years, our method looks for correlations between the orbital semimajor axis and the inverse size of Asteroids. This correlation is the signature of members of collisional families that have drifted from a common centre under the effect of the Yarkovsky thermal effect. Results. We identify two previously unknown families in the inner main belt among the moderate-albedo X-complex Asteroids. One of them, whose lowest numbered Asteroid is (161) Athor, is ~3 Gyr old, whereas the second one, whose lowest numbered object is (689) Zita, could be as old as the solar system. Members of this latter family have orbital eccentricities and inclinations that spread them over the entire inner main belt, which is an indication that this family could be primordial, that is, it formed before the giant planet orbital instability. Conclusions. The vast majority of moderate-albedo X-complex Asteroids of the inner main belt are genetically related, as they can be included into a few Asteroid families. Only nine X-complex Asteroids with moderate albedo of the inner main belt cannot be included in Asteroid families. We suggest that these bodies formed by direct accretion of the solids in the protoplanetary disc, and are thus surviving planetesimals.
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Gaia space mission and Asteroid spectroscopy
2017Co-Authors: Marco Delbo, Alberto Cellino, Laurent Galluccio, F. De Angeli, F. Mignard, P. TangaAbstract:Here we present the first Gaia spectroscopic observations of Asteroids. These data will be used to identify the composition of Asteroids. Gaia will obtain the largest spectroscopic survey of the Main Asteroid Belt.
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identification of a primordial Asteroid family constrains the original planetesimal population
Science, 2017Co-Authors: Marco Delbo, Kevin J Walsh, Chrysa Avdellidou, B Bolin, Alessandro MorbidelliAbstract:A quarter of known Asteroids is associated with more than 100 distinct Asteroid families, meaning that these Asteroids originate as impact fragments from the family parent bodies. The determination of which Asteroids of the remaining population are members of undiscovered families, or accreted as planetesimals from the protoplanetary disk, would constrain a critical phase of planetary formation by unveiling the unknown planetesimal size distribution. We discovered a 4-billion-year-old Asteroid family extending across the entire inner part of the main belt whose members include most of the dark Asteroids previously unlinked to families. This allows us to identify some original planetesimals, which are all larger than 35 kilometers, supporting the view of Asteroids being born big. Their number matches the known distinct meteorite parent bodies.
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In-Space Utilisation of Asteroids:: “Answers to Questions from the Asteroid Miners”
2016Co-Authors: Amara Graps, Line Drube, Daniel T. Britt, Grant Bonin, Simone Centuori, Martin Elvis, Marco Delbo, Rene Duffard, Philippe Blondel, Daniel FaberAbstract:The aim of the Asteroid Science Intersections with In-Space Mine Engineering (ASIME) 2016 conference on September 21-‐22, 2016 in Luxembourg City was to provide an environment for the detailed discussion of the specific properties of Asteroids, with the engineering needs of space missions that utilize Asteroids. The ASIME 2016 Conference produced a layered record of discussions from the Asteroid scientists and the Asteroid miners to understand each other’s key concerns and to address key scientific questions from the Asteroid mining companies: Planetary Resources, Deep Space Industries and TransAstra. These Questions were the focus of the two day conference, were addressed by scientists inside and outside of the ASIME Conference and are the focus of this White Paper. The Questions from the Asteroid mining companies have been sorted into the three Asteroid science themes: 1) survey, 2) surface and 3) subsurface and 4) Other. The answers to those Questions have been provided by the scientists with their conference presentations or edited directly into an early open-‐access collaborative Google document (August 2016-‐October 2016), or inserted by A. Graps using additional reference materials. During the ASIME 2016 last two-‐hours, the scientists turned the Questions from the Asteroid Miners around by presenting their own key concerns: Questions from the Asteroid Scientists. These answers in this White Paper will point to the Science Knowledge Gaps (SKGs) for advancing the Asteroid in-‐space resource utilisation domain.
Josef Hanus - One of the best experts on this subject based on the ideXlab platform.
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Asteroids physical models from combined dense and sparse photometry and scaling of the yorp effect by the observed obliquity distribution
Astronomy and Astrophysics, 2013Co-Authors: Josef Hanus, B Carry, Brian D Warner, Frederick Pilcher, R Behrend, Milan Broz, Ján Ďurech, Anna Marciniak, Robert D. Stephens, Dina CapekAbstract:The larger number of models of Asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole Asteroid population. With a larger statistical sample we can study the physical properties of Asteroid populations, such as main-belt Asteroids or individual Asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of Asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all Asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine Asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of Asteroids used in our previous paper. We present 119 new Asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of Asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.
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Combining Asteroid models derived by lightcurve inversion with Asteroidal occultation silhouettes
Icarus, 2011Co-Authors: Josef Ďurech, Mikko Kaasalainen, D. Herald, Brad Timerson, Eric Frappa, John Talbot, Takahito Hayamizu, Josef Hanus, David Dunham, Brian D WarnerAbstract:► Asteroid sizes can be measured by observing occultations of stars by Asteroids. ► We combine shape models of 44 Asteroids with the available occultation data. ► We derive Asteroid effective diameters. ► In many cases, we solve the ambiguity of the pole direction. ► Lightcurve inversion combined with occultations leads to unique physical models.
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Combining Asteroid models derived by lightcurve inversion with Asteroidal occultation silhouettes
Icarus, 2011Co-Authors: Josef Ďurech, David W. Dunham, Mikko Kaasalainen, D. Herald, Brad Timerson, Eric Frappa, John Talbot, Takahito Hayamizu, Josef Hanus, Brian WarnerAbstract:Abstract Asteroid sizes can be directly measured by observing occultations of stars by Asteroids. When there are enough observations across the path of the shadow, the Asteroid’s projected silhouette can be reconstructed. Asteroid shape models derived from photometry by the lightcurve inversion method enable us to predict the orientation of an Asteroid for the time of occultation. By scaling the shape model to fit the occultation chords, we can determine the Asteroid size with a relative accuracy of typically ∼10%. We combine shape and spin state models of 44 Asteroids (14 of them are new or updated models) with the available occultation data to derive Asteroid effective diameters. In many cases, occultations allow us to reject one of two possible pole solutions that were derived from photometry. We show that by combining results obtained from lightcurve inversion with occultation timings, we can obtain unique physical models of Asteroids.
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a study of Asteroid pole latitude distribution based on an extended set of shape models derived by the lightcurve inversion method
Astronomy and Astrophysics, 2011Co-Authors: Josef Hanus, Frederick Pilcher, Milan Broz, Brian Warner, Robert D. Stephens, J ďurech, Julian Oey, L Bernasconi, S Casulli, R BehrendAbstract:Context. In the past decade, more than one hundred Asteroid models were derived using the lightcurve inversion method. Measured by the number of derived models, lightcurve inversion has become the leading method for Asteroid shape determination. Aims. Tens of thousands of sparse-in-time lightcurves from astrometric projects are publicly available. We investigate these data and use them in the lightcurve inversion method to derive new Asteroid models. By having a greater number of models with known physical properties, we can gain a better insight into the nature of individual objects and into the whole Asteroid population. Methods. We use sparse photometry from selected observatories from the AstDyS database (Asteroids – Dynamic Site), either alone or in combination with dense lightcurves, to determine new Asteroid models by the lightcurve inversion method. We investigate various correlations between several Asteroid parameters and characteristics such as the rotational state and diameter or family membership. We focus on the distribution of ecliptic latitudes of pole directions. We create a synthetic uniform distribution of latitudes, compute the method bias, and compare the results with the distribution of known models. We also construct a model for the long-term evolution of spins. Results. We present 80 new Asteroid models derived from combined data sets where sparse photometry is taken from the AstDyS database and dense lightcurves are from the Uppsala Asteroid Photometric Catalogue (UAPC) and from several individual observers. For 18 Asteroids, we present updated shape solutions based on new photometric data. For another 30 Asteroids we present their partial models, i.e., an accurate period value and an estimate of the ecliptic latitude of the pole. The addition of new models increases the total number of models derived by the lightcurve inversion method to ∼200. We also present a simple statistical analysis of physical properties of Asteroids where we look for possible correlations between various physical parameters with an emphasis on the spin vector. We present the observed and de-biased distributions of ecliptic latitudes with respect to different size ranges of Asteroids as well as a simple theoretical model of the latitude distribution and then compare its predictions with the observed distributions. From this analysis we find that the latitude distribution of small Asteroids (D 60 km) exhibits an evident excess of prograde rotators, probably of primordial origin.
Michael Mueller - One of the best experts on this subject based on the ideXlab platform.
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Asteroid thermophysical modeling
Asteroids IV, 2015Co-Authors: Marco Delbo, B. Rozitis, Joshua P. Emery, Michael Mueller, Maria Teresa CapriaAbstract:The field of Asteroid thermophysical modeling has experienced an extraordinary growth in the last ten 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 properties. These parameters can therefore be derived by thermophysical modeling of infrared data. Thermophysical modeling led to Asteroid size estimates that were confirmed at the few-percent level by later spacecraft visits. We discuss how instrumentation advances now allow mid-infrared interferometric observations as well as high-accuracy spectro-photometry, posing their own set of thermal-modeling challenges. We present major breakthroughs achieved in studies of the thermal inertia, a sensitive indicator for the nature of Asteroids soils, allowing us, for instance, to determine the grain size of Asteroidal regoliths. Thermal inertia also governs non-gravitational effects on Asteroid orbits, requiring thermophysical modeling for precise Asteroid dynamical studies. The radiative heating of Asteroids, meteoroids, and comets from the Sun also governs the thermal stress in surface material; only recently has it been recognized as a significant weathering process. Asteroid space missions with thermal infrared instruments are currently undergoing study at all major space agencies. This will require a high level of sophistication of thermophysical models in order to analyse high-quality spacecraft data.
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Thermal inertia of near-Earth Asteroids and implications for the magnitude of the Yarkovsky effect
Icarus, 2007Co-Authors: Marco Delbo, Aldo Dell'oro, Stefano Mottola, Alan W. Harris, Michael MuellerAbstract:Abstract Thermal inertia determines the temperature distribution over the surface of an Asteroid and therefore governs the magnitude the Yarkovsky effect. The latter causes gradual drifting of the orbits of km-sized Asteroids and plays an important role in the delivery of near-Earth Asteroids (NEAs) from the main belt and in the dynamical spreading of Asteroid families. At present, very little is known about the thermal inertia of Asteroids in the km size range. Here we show that the average thermal inertia of a sample of NEAs in the km-size range is 200 ± 40 J m −2 s −0.5 K −1 . Furthermore, we identify a trend of increasing thermal inertia with decreasing Asteroid diameter, D . This indicates that the dependence of the drift rate of the orbital semimajor axis on the size of Asteroids due to the Yarkovsky effect is a more complex function than the generally adopted D −1 dependence, and that the size distribution of objects injected by Yarkovsky-driven orbital mobility into the NEA source regions is less skewed to smaller sizes than generally assumed. We discuss how this fact may help to explain the small difference in the slope of the size distribution of km-sized NEAs and main-belt Asteroids.
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Thermal Inertia of near-Earth Asteroids and Strength of the Yarkovsky Effect
Bulletin of the American Astronomical Society, 2006Co-Authors: Marco Delbo, Aldo Dell'oro, Stefano Mottola, Alan W. Harris, Michael MuellerAbstract:Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an Asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized Asteroids and is invoked to explain the delivery of near-Earth Asteroids (NEAs) from the main belt. Moreover, measurements of thermal inertia provide information on the presence or absence of loose surface material, such as thermally insulating regolith or dust. At present, very little is known about the thermal inertia of Asteroids in the km size range. Using an extensive dataset of thermal infrared observations obtained at the Keck 1, the ESO 3.6m and the IRTF telescopes, we find that the mean thermal inertia of near-Earth Asteroids in the km-size range is 200 ± 50 J m-2 s-0.5 K-1 corresponding to a surface thermal conductivity of 0.03 ± 0.01 W m-1K-1. Combining this result with published values of Asteroid thermal inertias, we also identify a trend of increasing thermal inertia with decreasing Asteroid size. As a consequence, the dependence of the Yarkovsky-induced semimajor axis drift rate on object diameter, D, departs from the 1/D dependence commonly assumed in models of the dynamical evolution of Asteroids.
Alan W. Harris - One of the best experts on this subject based on the ideXlab platform.
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formation of Asteroid pairs by rotational fission
Nature, 2010Co-Authors: Petr Pravec, D Polishook, David Vokrouhlický, Daniel J. Scheeres, Alan W. Harris, A. Galád, O Vaduvescu, F Pozo, A Barr, P LongaAbstract:The increased interest in the observation of main-belt Asteroids in recent years has led to the identification of tens of Asteroid pairs, which follow near-identical orbits around the Sun even though they are not physically bound together. Rotational fission of larger bodies has been hypothesized as a mechanism for their formation, an idea that gains support with some new observations. Theory predicts that the mass ratios of two Asteroids in a pair will be than about 0.2 and that as the mass ratio approaches this upper limit, the spin period of the larger body is extended. Accordingly, photometric observations of 35 Asteroid pairs reveal none with mass ratios greater than 0.2, and as mass ratios approach 0.2, primary periods grow longer. This suggests that Asteroid pairs form by rotational fusion of a parent Asteroid into a short-lived proto-binary system. Rotational fission may explain the formation of pairs of Asteroids that have similar heliocentric orbits but are not bound together. These authors report photometric observations of a sample of Asteroid pairs revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. In agreement with crucial predictions, they do not find Asteroid pairs with mass ratios larger than 0.2, and as the mass ratio approaches 0.2 the primary period grows long. Pairs of Asteroids sharing similar heliocentric orbits, but not bound together, were found recently1,2,3. Backward integrations of their orbits indicated that they separated gently with low relative velocities, but did not provide additional insight into their formation mechanism. A previously hypothesized rotational fission process4 may explain their formation—critical predictions are that the mass ratios are less than about 0.2 and, as the mass ratio approaches this upper limit, the spin period of the larger body becomes long. Here we report photometric observations of a sample of Asteroid pairs, revealing that the primaries of pairs with mass ratios much less than 0.2 rotate rapidly, near their critical fission frequency. As the mass ratio approaches 0.2, the primary period grows long. This occurs as the total energy of the system approaches zero, requiring the Asteroid pair to extract an increasing fraction of energy from the primary's spin in order to escape. We do not find Asteroid pairs with mass ratios larger than 0.2. Rotationally fissioned systems beyond this limit have insufficient energy to disrupt. We conclude that Asteroid pairs are formed by the rotational fission of a parent Asteroid into a proto-binary system, which subsequently disrupts under its own internal system dynamics soon after formation.
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Thermal inertia of near-Earth Asteroids and implications for the magnitude of the Yarkovsky effect
Icarus, 2007Co-Authors: Marco Delbo, Aldo Dell'oro, Stefano Mottola, Alan W. Harris, Michael MuellerAbstract:Abstract Thermal inertia determines the temperature distribution over the surface of an Asteroid and therefore governs the magnitude the Yarkovsky effect. The latter causes gradual drifting of the orbits of km-sized Asteroids and plays an important role in the delivery of near-Earth Asteroids (NEAs) from the main belt and in the dynamical spreading of Asteroid families. At present, very little is known about the thermal inertia of Asteroids in the km size range. Here we show that the average thermal inertia of a sample of NEAs in the km-size range is 200 ± 40 J m −2 s −0.5 K −1 . Furthermore, we identify a trend of increasing thermal inertia with decreasing Asteroid diameter, D . This indicates that the dependence of the drift rate of the orbital semimajor axis on the size of Asteroids due to the Yarkovsky effect is a more complex function than the generally adopted D −1 dependence, and that the size distribution of objects injected by Yarkovsky-driven orbital mobility into the NEA source regions is less skewed to smaller sizes than generally assumed. We discuss how this fact may help to explain the small difference in the slope of the size distribution of km-sized NEAs and main-belt Asteroids.
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Thermal Inertia of near-Earth Asteroids and Strength of the Yarkovsky Effect
Bulletin of the American Astronomical Society, 2006Co-Authors: Marco Delbo, Aldo Dell'oro, Stefano Mottola, Alan W. Harris, Michael MuellerAbstract:Thermal inertia is the physical parameter that controls the temperature distribution over the surface of an Asteroid. It affects the strength of the Yarkovsky effect, which causes orbital drift of km-sized Asteroids and is invoked to explain the delivery of near-Earth Asteroids (NEAs) from the main belt. Moreover, measurements of thermal inertia provide information on the presence or absence of loose surface material, such as thermally insulating regolith or dust. At present, very little is known about the thermal inertia of Asteroids in the km size range. Using an extensive dataset of thermal infrared observations obtained at the Keck 1, the ESO 3.6m and the IRTF telescopes, we find that the mean thermal inertia of near-Earth Asteroids in the km-size range is 200 ± 50 J m-2 s-0.5 K-1 corresponding to a surface thermal conductivity of 0.03 ± 0.01 W m-1K-1. Combining this result with published values of Asteroid thermal inertias, we also identify a trend of increasing thermal inertia with decreasing Asteroid size. As a consequence, the dependence of the Yarkovsky-induced semimajor axis drift rate on object diameter, D, departs from the 1/D dependence commonly assumed in models of the dynamical evolution of Asteroids.
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Asteroids in the Thermal Infrared
2002Co-Authors: Alan W. Harris, J. S. V. LagerrosAbstract:The importance of the thermal-infrared spectra region for investigations of Asteroids lies traditionally in the dependence of the thermal emission of an Asteroid on its visual albedo and size. Knowledge of albedos and sizes is crucial in many areas of Asteroid research, such as mineralogy and taxonomy, the sice-frequency distribution of families and populations of Asteroids (e.g., near-Earth Asteroids), and the relationship between Asteroids in the outer solar system and comets. However, the rapid increase in the availability of computing power over the past decade has cleared the way for development of sophisticated thermophysical models of Asteroids with interesting new areas of application. Recent progress in the thermal modeling of Asteroids and observational work in the thermal infrared are described. The use of thermal models for the physical characterization of Asteroids and other applications is discussed.
B Carry - One of the best experts on this subject based on the ideXlab platform.
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olivine dominated a type Asteroids in the main belt distribution abundance and relation to families
Icarus, 2019Co-Authors: Francesca E Demeo, B Carry, D Polishook, Brian Burt, Henry H Hsieh, Nicholas Moskovitz, Richard P Binzel, T H BurbineAbstract:Abstract Differentiated Asteroids are rare in the main Asteroid belt despite evidence for ∼ 100 distinct differentiated bodies in the meteorite record. We have sought to understand why so few main-belt Asteroids differentiated and where those differentiated bodies or fragments reside. Using the Sloan Digital Sky Survey (SDSS) to search for a needle in a haystack we identify spectral A-type Asteroid candidates, olivine-dominated Asteroids that may represent mantle material of differentiated bodies. We have performed a near-infrared spectral survey with SpeX on the NASA IRTF and FIRE on the Magellan Telescope. We report results from having doubled the number of known A-type Asteroids. We deduce a new estimate for the overall abundance and distribution of this class of olivine-dominated Asteroids. We find A-type Asteroids account for less than 0.16% of all main-belt objects larger than 2 km and estimate there are a total of ∼ 600 A-type Asteroids above that size. They are found rather evenly distributed throughout the main belt, are even detected at the distance of the Cybele region, and have no statistically significant concentration in any Asteroid family. We conclude the most likely implication is the few fragments of olivine-dominated material in the main belt did not form locally, but instead were implanted as collisional fragments of bodies that formed elsewhere.
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Solar System evolution from compositional mapping of the Asteroid belt
Nature, 2014Co-Authors: Francesca E Demeo, B CarryAbstract:Advances in the discovery and characterization of Asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The Asteroids in the main Asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes. The main Asteroid belt, once regarded as a sort of dumping ground for the spent remnants of planet formation, has emerged in recent years as a region of dynamic activity that provides a window on the processes that are still shaping our Solar System and the many extrasolar planetary systems across the Universe. Francesca DeMeo and Benoit Carry review recent advances in the discovery and characterization of Asteroids. More than half a million Asteroids have been discovered and mapped since the 1980s, revealing remarkable diversity in size, composition and orbit. New evidence has demonstrated substantial mixing through planetary migration and the subsequent dynamical processes. Next year NASA's Dawn space probe is due to rendezvous with Ceres, the largest body in Asteroid belt and one recently proven to contain water, so many new developments in this field can be expected. Unexpected diversity in the Asteroids in the main Asteroid belt holds clues to mixing via planetary migration in the early Solar System.
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Asteroids physical models from combined dense and sparse photometry and scaling of the yorp effect by the observed obliquity distribution
Astronomy and Astrophysics, 2013Co-Authors: Josef Hanus, B Carry, Brian D Warner, Frederick Pilcher, R Behrend, Milan Broz, Ján Ďurech, Anna Marciniak, Robert D. Stephens, Dina CapekAbstract:The larger number of models of Asteroid shapes and their rotational states derived by the lightcurve inversion give us better insight into both the nature of individual objects and the whole Asteroid population. With a larger statistical sample we can study the physical properties of Asteroid populations, such as main-belt Asteroids or individual Asteroid families, in more detail. Shape models can also be used in combination with other types of observational data (IR, adaptive optics images, stellar occultations), e.g., to determine sizes and thermal properties. We use all available photometric data of Asteroids to derive their physical models by the lightcurve inversion method and compare the observed pole latitude distributions of all Asteroids with known convex shape models with the simulated pole latitude distributions. We used classical dense photometric lightcurves from several sources and sparse-in-time photometry from the U.S. Naval Observatory in Flagstaff, Catalina Sky Survey, and La Palma surveys (IAU codes 689, 703, 950) in the lightcurve inversion method to determine Asteroid convex models and their rotational states. We also extended a simple dynamical model for the spin evolution of Asteroids used in our previous paper. We present 119 new Asteroid models derived from combined dense and sparse-in-time photometry. We discuss the reliability of Asteroid shape models derived only from Catalina Sky Survey data (IAU code 703) and present 20 such models. By using different values for a scaling parameter cYORP (corresponds to the magnitude of the YORP momentum) in the dynamical model for the spin evolution and by comparing synthetics and observed pole-latitude distributions, we were able to constrain the typical values of the cYORP parameter as between 0.05 and 0.6.
