Near Earth Asteroids with measurable Yarkovsky effect
TL;DR: In this article, the Yarkovsky effect among near Earth asteroids (NEAs) was investigated by measuring the YARKovsky-related orbital drift from the orbital fit using a high precision dynamical model, including the Newtonian attraction of 16 massive asteroids and the planetary relativistic terms.
About: This article is published in Icarus.The article was published on 2013-05-01 and is currently open access. It has received 140 citations till now. The article focuses on the topics: Yarkovsky effect & Near-Earth object.
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TL;DR: In this paper, the authors describe the processing of the Gaia DR2 data, and describe the criteria used to select the sample published in Gaia DR 2, and explore the data set to assess its quality.
Abstract: Context. The Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center repository. Positions are provided for each Gaia observation at CCD level. As additional information, complementary to astrometry, the apparent brightness of SSOs in the unfiltered G band is also provided for selected observations.Aims. We explain the processing of SSO data, and describe the criteria we used to select the sample published in Gaia DR2. We then explore the data set to assess its quality.Methods. To exploit the main data product for the solar system in Gaia DR2, which is the epoch astrometry of asteroids, it is necessary to take into account the unusual properties of the uncertainty, as the position information is nearly one-dimensional. When this aspect is handled appropriately, an orbit fit can be obtained with post-fit residuals that are overall consistent with the a-priori error model that was used to define individual values of the astrometric uncertainty. The role of both random and systematic errors is described. The distribution of residuals allowed us to identify possible contaminants in the data set (such as stars). Photometry in the G band was compared to computed values from reference asteroid shapes and to the flux registered at the corresponding epochs by the red and blue photometers (RP and BP).Results. The overall astrometric performance is close to the expectations, with an optimal range of brightness G ~ 12 − 17. In this range, the typical transit-level accuracy is well below 1 mas. For fainter asteroids, the growing photon noise deteriorates the performance. Asteroids brighter than G ~ 12 are affected by a lower performance of the processing of their signals. The dramatic improvement brought by Gaia DR2 astrometry of SSOs is demonstrated by comparisons to the archive data and by preliminary tests on the detection of subtle non-gravitational effects.
584 citations
TL;DR: The OSIRIS-REx asteroid sample return mission target, (101955) Bennu (formerly 1999 RQ 36), is a half-kilometer near-Earth asteroid with an extraordinarily well constrained orbit as mentioned in this paper.
238 citations
Cites background or methods from "Near Earth Asteroids with measurabl..."
...Given an estimated value of AT and the assumed value of d, one can readily derive the time-averaged da/dt using Gauss’ planetary equations (Farnocchia et al. 2013b)....
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...As the Yarkovsky induced orbital drift depends on the osculating orbital elements (Farnocchia et al. 2013b), there are also commensurable variations in the da/dt evolution (see Fig....
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...More recently Nugent et al. (2012) and Farnocchia et al. (2013b) have estimated the Yarkovsky effect for a few tens of near-Earth asteroids by using a formulation that depends on a single parameter to be determined from the orbital fit....
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...The orbital predictions and the impact hazard assessment are then performed by a Monte Carlo simulation that accounts for both the Yarkovsky effect distribution and the orbital uncertainty (Farnocchia et al. 2013a; Farnocchia and Chesley 2014)....
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...Importantly, it requires no information about the physical characteristics or spin state of the asteroid, and so it can be implemented readily in cases where only astrometric information is available (e.g., Vokrouhlický et al. 2008; Chesley et al. 2008; Nugent et al. 2012; Farnocchia et al. 2013b)....
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TL;DR: A new approach to the asteroid family classification by combining the Hierarchical Clustering Method (HCM) with a method to add new members to existing families, which allows to solve some difficult cases of families overlapping in the proper elements space but generated by different collisional events.
191 citations
TL;DR: It is reported that the kilometre-sized asteroid (29075) 1950 DA is a rubble pile that is rotating faster than is allowed by gravity and friction and that the strengths of the forces are comparable to, though somewhat less than, the forces found between the grains of lunar regolith.
Abstract: Modelling and observations of the kilometre-sized asteroid (29075) 1950 DA reveal it to be a ‘rubble pile’ that is rotating faster than is allowed by gravity and friction; cohesive forces such as those in lunar regolith are required to prevent it breaking up. Some asteroids are solid bodies but others, known as 'rubble-pile' asteroids, are loose aggregates of sand- to boulder-sized components. The conventional view, that rubble piles are held together by gravitational and frictional forces alone, has recently been questioned. It has been suggested that small van der Waals forces between constituent grains may be an important factor. Here, Ben Rozitis et al. report that the kilometre-sized rubble-pile asteroid (29075) 1950 DA is rotating faster than the breakup limit for its density calculated assuming the action of gravity and friction alone. They conclude that inter-particle cohesive forces must be holding the asteroid together and that the forces are comparable to, though somewhat less than, those found between the grains of lunar regolith. Space missions1 and ground-based observations2 have shown that some asteroids are loose collections of rubble rather than solid bodies. The physical behaviour of such ‘rubble-pile’ asteroids has been traditionally described using only gravitational and frictional forces within a granular material3. Cohesive forces in the form of small van der Waals forces between constituent grains have recently been predicted to be important for small rubble piles (ten kilometres across or less), and could potentially explain fast rotation rates in the small-asteroid population4,5,6. The strongest evidence so far has come from an analysis of the rotational breakup of the main-belt comet P/2013 R3 (ref. 7), although that was indirect and poorly constrained by observations. Here we report that the kilometre-sized asteroid (29075) 1950 DA (ref. 8) is a rubble pile that is rotating faster than is allowed by gravity and friction. We find that cohesive forces are required to prevent surface mass shedding and structural failure, and that the strengths of the forces are comparable to, though somewhat less than, the forces found between the grains of lunar regolith.
186 citations
TL;DR: In this article, the authors presented a new four-dimensional model of the near-Earth objects population that describes debiased steady-state distributions of semimajor axis, eccentricity, inclination, and absolute magnitude H in the range 17.962 − 56 + 52 + 52 ( 802 − 42 + 48 × 10 3 ) NEOs with H.
171 citations
References
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TL;DR: In this article, the high frequency portion of the spherical harmonic Mars gravity field was improved by tracking data collection from the MRO spacecraft, and the new JPL Mars gravity fields, MRO110B and MRO 110B2, show resolution near degree 90.
363 citations
TL;DR: The most abundant binary population is that of close binary systems among near-Earth, Mars-crossing, and main belt asteroids that have a primary diameter of about 10 km or smaller as mentioned in this paper.
282 citations
TL;DR: In this paper, 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, indicating 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.
261 citations
"Near Earth Asteroids with measurabl..." refers methods in this paper
...The rectangles correspond to reasonable values of q according to the taxonomic type and to a reasonable range of C (Delbó et al., 2007)....
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TL;DR: In this article, the authors derived orbital elements and nongravitational parameters from observations at every apparition of the periodic comets Honda-Mrkos-Pajdusakova, Faye, Tempel 2, Biela, Brorsen, and Tempel-Swift.
Abstract: Orbital elements and nongravitational parameters are derived from observations at every apparition of the periodic comets Honda-Mrkos-Pajdusakova, Faye, Tempel 2, Biela, Brorsen, and Tempel-Swift. For all except the first comet, the observations go back a century and more, although the last three comets have failed to reappear for some considerable time. The circumstances of the splitting of P/Biela are studied, and it is shown that the motion of the primary component was scarcely affected; it is also demonstrated that, if the primary still exists, it may pass only 0.05 AU from the earth in November 1971. An up-to-date list of mass-loss rates from comets is presented. It is found that, while most of the reliable determinations indicate that the cometary nongravitational effects decrease with time, there are a few cases where the effects increase slightly. The former situation is discussed in terms of a nuclear core-mantle model, implying that these comets will eventually evolve into inert, asteroidal objects, while the nuclei of the other comets are interpreted as coreless, eventually to disappear completely (or almost completely).
245 citations
01 Mar 2002
TL;DR: The Yarkovsky effect is a thermal radiation force that causes objects to undergo semimajor axis drift and spinup/spindown as a function of their spin, orbit, and material properties as mentioned in this paper.
Abstract: The Yarkovsky effect is a thermal radiation force that causes objects to undergo semimajor axis drift and spinup/spindown as a function of their spin, orbit, and material properties. This mechanism can be used to (1) deliver asteroids (and meteoroids) with diameter D < 20 km from their parent bodies in the main belt to chaotic resonance zones capable of transporting this material to Earth-crossing orbits, (2) disperse asteroid families, with drifting bodies jumping or becoming trapped in mean-motion and secular resonances within the main belt, and (3) modify the rotation rates of asteroids a few kilometers in diameter or smaller enough to possibly explain the excessive number of very fast and very slow rotators among the small asteroids. Accordingly, we suggest that nongravitational forces, which produce small but meaningful effects on asteroid orbits and rotation rates over long timescales, should now be considered as important as collisions and gravitational perturbations to our overall understanding of asteroid evolution.
208 citations
"Near Earth Asteroids with measurabl..." refers background or methods in this paper
...Observations of Small Solar System Bodies with GAIA....
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...This excess of retrograde rotators can be explained by the nature of resonance feeding into the inner Solar System (Bottke et al., 2002)....
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...We discussed how this excess of retrograde rotators can be related to the delivery of NEAs to the inner Solar System....
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...Bottke et al. (2002) report that 37% of NEAs arrive via ν6 resonance....
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...For this population, 55% are expected to arrive from ν6 according to the Bottke et al. (2002) NEO model (Bottke, personal communication), a much greater fraction than for NEAs as a whole....
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