Minor Planet Publications Used in
Preparing the 2005 Triennial Report
The ADS abstract service (http://adsabs.harvard.edu/abstract_service.html)
was searched for papers appearing in refereed publications during the period
between July 2002 and June 2005, inclusive, on the terms ` “asteroid” OR “minor
planet” ‘. This returned 665 abstracts from which we selected 339 as falling
under the purview of the Physical Studies of Minor Planets Working Group. That
is, no purely meteoritical, theoretical, dynamical, or astrometric studies were
included. However, papers on these topics from which physical properties such
as Yarkovsky effect, size-frequency distributions, masses, etc., were included.
The 339 relevant papers were
sorted into twelve categories and a brief description of the scientific results
in each category was written citing a subset of them. The titles and abstracts
for the entire list of 339 papers appear below. The order of this list is that
returned by the ADS search engine, i.e., it is not in alphabetical or
chronological order. A paper cited in the IAU Triennial Report can be located
using the browser or PDF reader’s “Find” function.
This list was prepared by A.
Cellino and E. Tedesco on 12 September 2005
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Title: |
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Widespread magma oceans on asteroidal bodies in the early Solar System |
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Authors: |
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Greenwood, Richard C.; Franchi, Ian A.; Jambon, Albert; Buchanan, Paul C. |
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Journal: |
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Nature, Volume 435, Issue 7044, pp. 916-918 (2005). (Nature Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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NATURE |
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Abstract Copyright: |
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(c) 2005: Nature |
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DOI: |
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Bibliographic Code: |
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2005Natur.435..916G |
Immediately following the
formation of the Solar System, small planetary bodies accreted, some of which
melted to produce igneous rocks. Over a longer timescale (15-33Myr), the inner
planets grew by incorporation of these smaller objects through collisions.
Processes operating on such asteroids strongly influenced the final composition
of these planets, including Earth. Currently there is little agreement about
the nature of asteroidal igneous activity: proposals range from small-scale
melting, to near total fusion and the formation of deep magma oceans. Here we
report a study of oxygen isotopes in two basaltic meteorite suites, the HEDs
(howardites, eucrites and diogenites, which are thought to sample the asteroid
4 Vesta) and the angrites (from an unidentified asteroidal source). Our results
demonstrate that these meteorite suites formed during early, global-scale
melting (>= 50 per cent) events. We show that magma oceans were present on
all the differentiated Solar System bodies so far sampled. Magma oceans
produced compositionally layered planetesimals; the modification of such bodies
before incorporation into larger objects can explain some anomalous planetary
features, such as Earth's high Mg/Si ratio.
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Title: |
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Yarkovsky origin of the unstable asteroids in the 2/1 mean motion resonance with Jupiter |
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Authors: |
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Brož, M.; Vokrouhlický, D.; Roig, F.; Nesvorný, D.; Bottke, W. F.; Morbidelli, A. |
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Affiliation: |
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AA(Institute of Astronomy, Charles University, Prague, V Holešovičkách 2, 18000 Prague 8, Czech Republic), AB(Institute of Astronomy, Charles University, Prague, V Holešovičkách 2, 18000 Prague 8, Czech Republic), AC(Observatório Nacional - MCT, Rua Gal. José Cristino 77, Rio de Janeiro, 20921-400 RJ, Brazil), AD(Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302, USA), AE(Department of Space Studies, Southwest Research Institute, 1050 Walnut St., Suite 400, Boulder, CO 80302, USA), AF(Observatoire de la Côte d'Azur, Dept. Cassiopee, BP 4224, 06304 Nice Cedex 4, France) |
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Journal: |
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Monthly Notices of the Royal Astronomical Society, Volume 359, Issue 4, pp. 1437-1455. (MNRAS Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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MNRAS |
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Abstract Copyright: |
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(c) 2005 RAS |
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DOI: |
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Bibliographic Code: |
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2005MNRAS.359.1437B |
The 2/1 mean
motion resonance with Jupiter, intersecting the main asteroid belt at ~3.27 au,
contains a small population of objects. Numerical investigations have
classified three groups within this population: asteroids residing on stable
orbits (i.e. Zhongguos), those on marginally stable orbits with dynamical
lifetimes of the order of 100 Myr (i.e. Griquas), and those on unstable orbits.
In this paper, we reexamine the origin, evolution and survivability of objects
in the 2/1 population. Using recent asteroid survey data, we have identified
100 new members since the last search, which increases the resonant population
to 153. The most interesting new asteroids are those located in the
theoretically predicted stable island A, which until now had been thought to be
empty. We also investigate whether the population of objects residing on the
unstable orbits could be resupplied by material from the edges of the 2/1
resonance by the thermal drag force known as the Yarkovsky effect (and by the
YORP effect, which is related to the rotational dynamics). Using N-body
simulations, we show that test particles pushed into the 2/1 resonance by the
Yarkovsky effect visit the regions occupied by the unstable asteroids. We also
find that our test bodies have dynamical lifetimes consistent with the
integrated orbits of the unstable population. Using a semi-analytical
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Title: |
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Spectral study of the Eunomia asteroid family |
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Authors: |
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Nathues, Andreas; Mottola, Stefano; Kaasalainen, Mikko; Neukum, Gerhard |
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Affiliation: |
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AA(Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Straße 2, 37191 Katlenburg-Lindau, Germany), AB(DLR, Institute of Space Sensor Technology and Planetary Exploration, Rutherfordstrasse 2, 12489 Berlin, Germany), AC(Rolf Nevanlinna Institute, Department of Mathematics and Statistics, P.O. Box 68, 00014 University of Helsinki, Finland), AD(Freie Universität Berlin, Institut für Geologie, Geophysik und Geoinformatik, Malteserstraße 74-100, D-12249 Berlin, Germany) |
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Journal: |
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Icarus, Volume 175, Issue 2, p. 452-463. (Icarus Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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ELSEVIER |
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Abstract Copyright: |
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(c) 2005 Elsevier Science B.V. All rights reserved. |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..452N |
We present color ratio curves of
the S-Asteroid 15 Eunomia, which have been extracted from high-precision
photometric lightcurves obtained in three different VNIR wavelength bands at
the Bochum Telescope, La Silla. The measured color ratio curves and near
infrared spectra were used to derive a detailed surface composition model whose
shape has been computed by V-lightcurve inversions. According to this analysis,
the asteroid shows on one hemisphere a higher concentration of pyroxene, which
causes an increased 440/700 nm and a reduced 940/700 nm reflectance ratio as
well as a pronounced 2-μm absorption band. The remaining surface shows a higher
concentration of olivine, leading to a reduced 440/700 nm and slightly
increased 940/700 nm color ratio. In addition, we found that the maximum of the
440/700 nm color ratio curve coincide with the minimum of the 940/700 nm color
ratio curve and vice versa. We demonstrate on the basis of USGS laboratory
spectra that this anti-cyclical behavior can be explained by choosing Fe-rich
olivine and a pyroxene with moderate Fe content as varying mineral phases.
Furthermore, our observations confirm that 15 Eunomia is an irregular elongated
and at least partially differentiated body. Previous spectral investigations of
several smaller fragments of the Eunomia asteroid family revealed that the
amount of fragments showing an increased pyroxene content exceeds the amount of
pyroxene-poor fragments (Nathues, 2000, DLR Forschungsbericht, ISSN 1434-8454).
This finding together with the observation that the major fraction of Eunomia's
surface is enriched in olivine let us claim that a large fraction of the
original pyroxene-enriched crust layer has been lost due to a major collision
that created the Eunomia asteroid family. Significant spectral evidences,
consistent with high concentrations of metals have been found neither in the
rotational resolved spectra of 15 Eunomia nor in its fragments. This led to the
conclusion that either no core consisting mainly of metals exists or that an
eventual one has not been unearthed by the impact.
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Title: |
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The spin state of 433 Eros and its possible implications |
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Authors: |
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Affiliation: |
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AA(Institute of Astronomy, Charles University, V Holešovičkách 2, CZ-18000 Prague 8, Czech Republic), AB(Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA), AC(Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA) |
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Journal: |
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Icarus, Volume 175, Issue 2, p. 419-434. (Icarus Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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ELSEVIER |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..419V |
In this paper, we show that
Asteroid (433) Eros is currently residing in a spin orbit resonance, with its
spin axis undergoing a small-amplitude libration about the Cassini state 2 of
the proper mode in the nonsingular orbital element sinI/2exp(ıΩ), where I the
orbital inclination and Ω the longitude of the node. The period of this
libration is ≃53.4 kyr. By excluding these
libration wiggles, we find that Eros' pole precesses with the proper orbital
plane in inertial space with a period of ≃61.4
kyr. Eros' resonant state forces its obliquity to oscillate with a period of
≃53.4 kyr between ≃76° and
≃89.5°. The observed value of ≃89°
places it near the latter extreme of this cycle. We have used these results to
probe Eros' past orbit and spin evolution. Our computations suggest that Eros
is unlikely to have achieved its current spin state by solar and planetary
gravitational perturbations alone. We hypothesize that some dissipative process
such as thermal torques (e.g., the so-called YORP effect) may be needed in our
model to obtain a more satisfactory match with data. A detailed study of this
problem is left for future work.
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Title: |
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An equal-area map projection for irregular objects |
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Authors: |
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Affiliation: |
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Center for Radiophysics and Space Research, 306 Space
Sciences, |
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Journal: |
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Icarus, Volume 175, Issue 2, p. 382-389. (Icarus Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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ELSEVIER |
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Abstract Copyright: |
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(c) 2005 Elsevier Science B.V. All rights reserved. |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..382B |
An increasing number of objects
discovered in the Solar System have irregular shapes which require
unconventional mapping techniques. Here we present a technique that produces
equivalent maps of such objects. As such maps preserve surface area they are
especially useful for mapping the distribution of geological features on
irregular objects. Maps of blocks and craters on the Asteroid 433 Eros are used
to illustrate the potential use of the technique. Two equal-area maps are
adequate to cover the entire asteroid and convincingly demonstrate variations
in surface density of mapped features. Similar coverage by orthographic views
requires 4 to 6 plots. The distortion of the maps are
comparable to the distortions of maps created by other techniques.
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Title: |
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The Statistical Asteroid Model. I. The Main-Belt Population for Diameters Greater than 1 Kilometer |
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Authors: |
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Affiliation: |
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AA(Space
Science Center, University of New Hampshire, Durham, NH 03824; ), AB(INAF - Osservatorio Astronomico di Torino, 10025 Pino
Torinese, Torino, Italy; , ), AC(INAF - Osservatorio Astronomico di Torino, 10025 Pino
Torinese, Torino, Italy; , ) |
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Journal: |
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The Astronomical Journal, Volume 129, Issue 6, pp. 2869-2886. (AJ Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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UCP |
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AJ Keywords: |
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Infrared: Solar System, Minor Planets, Asteroids, Solar System: General |
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Abstract Copyright: |
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(c) 2005: The American Astronomical Society |
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DOI: |
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Bibliographic Code: |
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2005AJ....129.2869T |
We describe the creation of a
model of the main asteroid belt whose purpose is to describe the main-belt
asteroid size frequency distribution and simulate the number of main-belt
asteroids and their fluxes at visual through mid-infrared (~0.3-70 μm)
wavelengths in any area of sky for an arbitrary date. This model is based on a
population of ~1.9×106 asteroids obtained from the complete known
asteroid sample, plus extrapolation of the size-frequency distributions of 15
asteroid dynamical families and three background populations, to a diameter
limit of 1 km. The model is compared with data and other models, example
applications are given, planned refinements and extensions to the model are
presented, and some implications of the resulting size frequency distribution
are discussed.
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Title: |
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Analysis of near-IR spectra of 1 Ceres and 4 Vesta, targets of the Dawn mission |
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Authors: |
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Vernazza, P.; Mothé-Diniz, T.; Barucci, M. A.; Birlan, M.; Carvano, J. M.; Strazzulla, G.; Fulchignoni, M.; Migliorini, A. |
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Affiliation: |
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AA(LESIA, Observatoire de Paris, 92195 Meudon Principal
Cedex, France ), AB(LESIA, Observatoire de Paris, 92195 Meudon Principal Cedex,
France), AC(LESIA, Observatoire de Paris, 92195 Meudon Principal Cedex,
France), AD(IMCCE, Observatoire de Paris, 77 Av. Denfert Rochereau, 75014 Paris Cedex, France),
AE(LESIA, Observatoire de Paris, 92195 Meudon Principal Cedex, France),
AF(INAF-Osservatorio Astrofisico di Catania, via Santa Sofia 78, 95123
Catania, Italy), AG(LESIA, Observatoire de Paris, 92195 Meudon Principal
Cedex, France), AH(LESIA, Observatoire de Paris, 92195 Meudon Principal
Cedex, France; Dipartimento di Astronomia di Padova, Vicolo dell'Osservatorio
2, 35122 Padova, Italy) |
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Journal: |
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Astronomy and Astrophysics, Volume 436, Issue 3, June IV 2005, pp.1113-1121 (A&A Homepage) |
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Publication Date: |
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06/2005 |
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Origin: |
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EDP |
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Keywords: |
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minor planets, asteroids, techniques: spectroscopic, infrared: solar system |
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DOI: |
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Bibliographic Code: |
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2005A&A...436.1113V |
We obtained high signal to noise
spectra of the two targets of the Dawn mission, 4 Vesta and 1 Ceres from
observations carried out in remote control between the Observatoire de
Paris-Meudon and the NASA Infrared Telescope Facility on
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Title: |
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Nutational damping times in solids of revolution |
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Authors: |
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Affiliation: |
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AA(Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853, USA), AB(Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853, USA; Department of Astronomy, Cornell University, Ithaca, NY 14853, USA), AC(Department of Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853, USA) |
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Journal: |
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Monthly Notices of the Royal Astronomical Society, Volume 359, Issue 1, pp. 79-92. (MNRAS Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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MNRAS |
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Abstract Copyright: |
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(c) 2005 RAS |
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DOI: |
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Bibliographic Code: |
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2005MNRAS.359...79S |
We derive the characteristic
nutational damping time Td for a linear, anelastic ellipsoid of
revolution. Our calculation is based on the well-known idea that energy loss
within an isolated spinning body causes the axis of maximum inertia of the body
to align with its angular momentum vector, leading to pure spin. Energy loss
occurs within an anelastic material whenever internal stresses are time
variable; thus even freely rotating bodies in space, if they are wobbling, lose energy because internal stresses are
associated with the accelerations caused by nutation. We find that , where D(h) is a constant of the order of a few times
102 that depends on the shape of the body with h being the (aspect)
ratio of the lengths of axes to one another, μ is the elastic modulus, Q is a
quality factor that describes the anelasticity of the material, ρ is the
density of the body, a is its radius and Ω is an angular velocity. This functional
form of the damping time is consistent with previous results but is more
soundly based. Coefficients in past expressions vary between various authors, leading to predicted damping times that can differ
by factors of the order of 10. To estimate damping times for typical asteroids,
we choose values for the various parameters in this expression. We conclude
that the extent of energy dissipation was over, rather than underestimated, in
previous treatments. None the less, we argue that asteroids will generally be
found in pure rotation, unless objects are small, spinning slowly and recently
excited.
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Title: |
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Ceres: Evolution and current state |
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Authors: |
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Journal: |
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Journal of Geophysical Research, Volume 110, Issue E5, CiteID E05009 (JGRE Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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AGU |
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AGU Keywords: |
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Planetary Sciences: Solar System Objects: Asteroids, Planetary Sciences: Solid Surface Planets: Origin and evolution, Planetary Sciences: Solid Surface Planets: Composition (1060, 3672), Planetary Sciences: Solid Surface Planets: Surface materials and properties |
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Abstract Copyright: |
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(c) 2005: American Geophysical |
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DOI: |
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Bibliographic Code: |
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2005JGRE..11005009M |
We modeled several thermal
evolution scenarios for Ceres to explore the nature of large, wet protoplanets
and to predict current-day evidence that might be found by close inspection,
such as by the Dawn mission. The density for Ceres is near 2.1, suggesting a water content between 17% and 27% by mass. Short- and
long-lived radioactive nuclide heating is considered. Even if only long-lived
radionuclide heating is assumed, the water ice in Ceres melts quickly and a
water mantle forms, but an approximately 10-km crust does not melt. The
circulating warm water would alter the silicates. As heat is lost by conduction
through the frozen crust, water begins to freeze out at the base of the crust.
Solid-state convection begins and transports more heat as well as perhaps
material dissolved or entrained in the water to or near the surface. Ceres'
water layer eventually (but perhaps not entirely) freezes, forming a layered
density structure with perhaps some liquid water remaining today. Our
differentiated models are in agreement with the recently measured difference
between the equatorial and polar radii. We find that Ceres' existence and
evolution depend critically on it containing water at formation, and this
depends strongly on the combination of when it accreted and the amount of 26Al
present in the pre-Ceres ~1-km-sized objects; slightly more 26Al or
earlier accretion produces a dry Vesta-like object. Melting and freezing plus
mineralization would lead to several dimensional changes over time, creating
topographic features, zones of weakness, and perhaps disruptions in the crust.
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Title: |
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New V-type asteroids in near-Earth space |
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Authors: |
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Affiliation: |
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AA(Dipartimento
di Astronomia, Università di Padova, vicolo dell'Osservatorio 2, I-35122
Padova, Italy), AB(Dipartimento di Astronomia, Università di Padova, vicolo
dell'Osservatorio 2, I-35122 Padova, Italy), AC(Dipartimento di Fisica,
Università di Pisa, via Buonarroti 2, I-56127 Pisa, Italy), AD(Dipartimento
di Astronomia, Università di Padova, vicolo dell'Osservatorio 2, I-35122
Padova, Italy) |
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Journal: |
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Icarus, Volume 175, Issue 1, p. 170-174. (Icarus Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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ELSEVIER |
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Abstract Copyright: |
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(c) 2005 Elsevier Science B.V. All rights reserved. |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..170M |
We present new visible and
near-infrared spectroscopic observations of 4 small, previously unclassified, near-Earth objects (NEOs). They appear to have
basaltic surfaces, and hence they can be classified as V-types. Their visible
spectra exhibit a closer spectral match with the Main-Belt (MB) Asteroid (4)
Vesta than the other, presently known, V-type NEOs and MB asteroids. The
near-infrared spectrum of Asteroid 2003 FT3 shows—for the first time among
NEOs—a peculiar shape of the 1 μm band, maybe suggesting an overabundance of
olivine compared to the other V-types and to (4) Vesta. The presence of V-type
objects among NEOs may be a consequence of the delivery processes connecting
the inner MB to the near-Earth region. On the basis of the orbital parameters
of the NEOs presented here, both the resonances (3:1 and ν6),
usually considered as the most relevant gateways for the production of
near-Earth asteroids, should have been active to transfer the bodies from the
MB region.
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Title: |
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Dust transport in photoelectron layers and the formation of dust ponds on Eros |
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Authors: |
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Colwell, Joshua E.; Gulbis, Amanda A. S.; Horányi, Mihály; Robertson, Scott |
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Affiliation: |
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AA(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392, USA), AB(Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA), AC(Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309-0392, USA), AD(Center for Integrated Plasma Studies, University of Colorado, Boulder, CO 80309-0390, USA) |
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Journal: |
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Icarus, Volume 175, Issue 1, p. 159-169. (Icarus Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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ELSEVIER |
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Abstract Copyright: |
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(c) 2005 Elsevier Science B.V. All rights reserved. |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..159C |
We investigate the electrostatic
transport of charged dust in the photoelectron layer over the dayside surface
of an asteroid. Micron-sized dust particles may be levitated above the surface
in the photoelectron layer. Horizontal transport within the layer can then lead
to net deposition of dust into shadowed regions where the electric field due to
the photoelectron layer disappears. We apply a 2D numerical model simulating
charged dust dynamics in the near-surface daytime plasma environment of
Asteroid 433 Eros to the formation of dust deposits in craters. We find that
dust tends to collect in craters and regions of shadow. This electrostatic dust
transport mechanism may contribute to the formation of smooth dust ponds
observed by the NEAR-Shoemaker spacecraft at Eros. The size distribution of
transported dust depends on the particle density and work function, and the
work function of the surface and solar wind electron temperature and density.
With reasonable values for these parameters, μm-sized and smaller particles are
levitated at Eros. Micrometeoroid bombardment is not a sufficient source
mechanism for electrostatic transport to create the Eros dust ponds. Laboratory
measurements of dust in a plasma sheath show that dust launched off the surface
by direct electrostatic levitation can provide a sufficient source for
transport to produce the observed Eros ponds.
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Title: |
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Near-IR spectral evidence for the presence of iron-poor orthopyroxenes on the surfaces of six M-type asteroids |
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Authors: |
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Affiliation: |
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AA(Department of Space Studies, Room 526, Box 9008, University of North Dakota, Grand Forks, ND 58202, USA), AB(Department of Space Studies, Room 518, Box 9008, University of North Dakota, Grand Forks, ND 58202, USA; Visiting astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement No. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program.), AC(NASA Johnson Space Center, Mail Code SR, Houston, TX 77058, USA; Visiting astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement No. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program.) |
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Journal: |
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Icarus, Volume 175, Issue 1, p. 141-158. (Icarus Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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ELSEVIER |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..141H |
The first verifiable near-infrared
absorption features in the ∼0.9-μm spectral region are reported for Asteroids
16 Psyche, 69 Hesperia, 110
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Title: |
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The fossilized size distribution of the main asteroid belt |
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Authors: |
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Bottke, William F.; Durda, Daniel D.; Nesvorný, David; Jedicke, Robert; Morbidelli, Alessandro; Vokrouhlický, David; Levison, Hal |
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Affiliation: |
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AA(Department of Space Studies, Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA), AB(Department of Space Studies, Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA), AC(Department of Space Studies, Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA), AD(Institute for Astronomy, University of Hawaii, Honolulu, HI 96822-1897, USA), AE(Observatoire de la Côte d'Azur, B.P. 4229, 06034 Nice Cedex 4, France), AF(Institute of Astronomy, Charles University, V Holešovičkách 2, 180 00 Prague 8, Czech Republic), AG(Department of Space Studies, Southwest Research Institute, 1050 Walnut St, Suite 400, Boulder, CO 80302, USA) |
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Journal: |
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Icarus, Volume 175, Issue 1, p. 111-140. (Icarus Homepage) |
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Publication Date: |
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05/2005 |
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Origin: |
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ELSEVIER |
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DOI: |
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Bibliographic Code: |
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2005Icar..175..111B |
Planet formation models suggest
the primordial main belt experienced a short but intense period of collisional
evolution shortly after the formation of planetary embryos. This period is
believed to have lasted until Jupiter reached its full size, when dynamical
processes (e.g., sweeping resonances, excitation via planetary embryos) ejected
most planetesimals from the main belt zone. The few planetesimals left behind
continued to undergo comminution at a reduced rate until the present day. We
investigated how this scenario affects the main belt size distribution over
Solar System history using a collisional evolution model (CoEM) that accounts
for these events. CoEM does not explicitly include results from dynamical
models, but instead treats the unknown size of the primordial main belt and the
nature/timing of its dynamical depletion using innovative but approximate
methods. Model constraints were provided by the observed size frequency
distribution of the asteroid belt, the observed population of asteroid
families, the cratered surface of differentiated Asteroid (4) Vesta, and the
relatively constant crater production rate of the Earth and Moon over the last
3 Gyr. Using CoEM, we solved for both the shape of the initial main belt size
distribution after accretion and the asteroid disruption scaling law QD∗. In contrast to previous efforts, we find our derived QD∗ function is very similar to results produced by numerical
hydrocode simulations of asteroid impacts. Our best fit results suggest the
asteroid belt experienced as much comminution over its early history as it has
since it reached its low-mass state approximately 3.9 4.5 Ga. These results
suggest the main belt's wavy-shaped size-frequency distribution is a “fossil”
from this violent early epoch. We find that most diameter D≳120 km asteroids are primordial, with their physical
properties likely determined during the accretion epoch. Conversely, most smaller asteroids are byproducts of fragmentation
events. The observed changes in the asteroid spin rate and lightcurve distributions
near D∼100 120 km are likely to be a byproduct of this difference. Estimates
based on our results imply the primordial main belt population (in the form of
D<1000 km bodies) was 150 250 times larger than it is today, in agreement
with recent dynamical simulations.
|
Title: |
|
Optical and thermal infrared observations of six near-Earth asteroids in 2002 |
|
Authors: |
|
Wolters, Stephen D.; Green, Simon F.; McBride, Neil; Davies, John K. |
|
Affiliation: |
|
AA(Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes, Buckinghamshire, MK7 6AA, UK), AB(Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes, Buckinghamshire, MK7 6AA, UK), AC(Planetary and Space Sciences Research Institute, The Open University, Walton Hall, Milton Keynes, Buckinghamshire, MK7 6AA, UK), AD(Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK) |
|
Journal: |
|
Icarus, Volume 175, Issue 1, p. 92-110. (Icarus Homepage) |
|
Publication Date: |
|
05/2005 |
|
Origin: |
|
ELSEVIER |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..175...92W |
We present thermal infrared
photometry and spectrophotometry of six Near-Earth Asteroids (NEAs) using the
3.8 m United Kingdom Infrared Telescope (UKIRT) together with
quasi-simultaneous optical observations of five NEAs taken at the 1.0 m Jacobus
Kapteyn Telescope (JKT). For Asteroid (6455) 1992 HE we derive a rotational
period P=2.736±0.002 h, and an absolute visual magnitude H=14.32±0.24. For
Asteroid 2002 HK12 we derive H=18.22(+0.37,−0.30).
The Standard Thermal Model (STM), the Fast Rotating Model (FRM) and the
Near-Earth Asteroid Thermal Model (NEATM) have been fitted to the measured
fluxes to derive albedos and effective diameters. The derived geometric albedos
and effective diameters are (6455) 1992 HE: pv=0.26±0.08, Deff=3.55±0.5
km; 1999 HF1: pv=0.18±0.07, Deff=3.73(+1.0,−0.5)
km; 2000 ED104: pv=0.18±0.05, Deff=1.21±0.2
km; 2002 HK12: pv=0.24(+0.25,−0.11), Deff=0.62±0.2
km; 2002 NX18: pv=0.031±0.009, Deff=2.24±0.3
km; 2002 QE15: pv=0.15(+0.08,−0.06), Deff=1.94±0.4
km. The limitations of using the NEATM to observe NEAs at high phase angles are
discussed.
|
Title: |
|
The High-Albedo Kuiper Belt Object (55565) 2002 AW197 |
|
Authors: |
|
Cruikshank, Dale P.; Stansberry, John A.; Emery, Joshua P.; Fernández, Yanga R.; Werner, Michael W.; Trilling, David E.; Rieke, George H. |
|
Affiliation: |
|
AA(NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035-1000 .), AB(Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065.), AC(Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065.; SETI Institute, 2035 Landings Drive, Mountain View, CA 94043.), AD(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822.), AE(Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109.), AF(Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065.), AG(Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065.) |
|
Journal: |
|
The Astrophysical Journal, Volume 624, Issue 1, pp. L53-L56. (ApJ Homepage) |
|
Publication Date: |
|
05/2005 |
|
Origin: |
|
UCP |
|
ApJ Keywords: |
|
Infrared: Solar System, Kuiper Belt, Minor Planets, Asteroids |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005ApJ...624L..53C |
We detected thermal emission from
the Kuiper Belt object 2002 AW197 in 2003 December and again in 2004
April using the Multiband Imaging Photometer on the Spitzer Space Telescope. In
combination with the absolute visual magnitude, the thermal measurements
indicate a geometric albedo of 0.17+/-0.03 and a diameter of 700+/-50 km. The
albedo of 2002 AW197 is significantly higher than the 0.04 value
typically assumed for trans-Neptunian objects, and consequently the object is
smaller than previously thought based on that assumption. Our thermal
measurements at two wavelengths (24 and 70 μm) allow us to constrain the
surface temperature and thereby place constraints on the thermal inertia. We
find that the standard thermal model (STM) is inconsistent with the 24/70 μm
color unless we set the beaming parameter η>0.95, indicating that the object
has a significant thermal inertia and, therefore, that the STM is
inappropriate. The other end-member thermal inertia model is the fast-rotator,
or isothermal-latitude, model (ILM). The data are well represented by an ILM
with the pole of rotation inclined to the Sun by 45deg+/-10deg.Â
The high albedo is consistent with a surface containing significant amounts of
weakly absorbing materials, with ices and/or fine-grained silicates as likely
candidates.
|
Title: |
|
Search for Activity in 3200 Phaethon |
|
Authors: |
|
|
|
Affiliation: |
|
AA(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822; , ), AB(Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822; , ) |
|
Journal: |
|
The Astrophysical Journal, Volume 624, Issue 2, pp. 1093-1096. (ApJ Homepage) |
|
Publication Date: |
|
05/2005 |
|
Origin: |
|
UCP |
|
ApJ Keywords: |
|
Comets: General, Meteors, Meteoroids, Minor Planets, Asteroids |
|
Abstract Copyright: |
|
(c) 2005: The American Astronomical Society |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005ApJ...624.1093H |
We present deep optical imaging of
Geminid meteor stream parent 3200 Phaethon taken in search of low-level
cometary activity (i.e., coma or dust trail). Although no unambiguous cometary
behavior was observed, we find an upper limit on the object's cometary
mass-loss rate of Ṁlim~0.01 kg s-1.
The corresponding active fraction (the fraction of the surface area that could
consist of freely sublimating water ice) is f<=7×10-6, at least 2
orders of magnitude smaller than other known comets.
|
Title: |
|
The high frequency variations in the rotation of Eros |
|
Authors: |
|
|
|
Affiliation: |
|
AA(Observatoire de Paris, SYRTE, UMR 8630 du CNRS, 61
avenue de l'Observatoire, 75014 |
|
Journal: |
|
Astronomy and Astrophysics, Volume 433, Issue 1, April I 2005, pp.375-383 (A&A Homepage) |
|
Publication Date: |
|
04/2005 |
|
Origin: |
|
EDP |
|
Keywords: |
|
minor planets, asteroids, celestial mechanics, astrometry |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005A&A...433..375S |
We use very precise information
concerning the physical properties of the asteroid Eros 433, obtained by the
NEAR probe mission, to analytically compute the modifications of its rotation
on a short time scale, with a precision never reached before for an asteroid.
Two kinds of components are investigated here: the free rotation and the forced
one, due to the gravitational torque exerted by the Sun. Coefficients of the
short periodic part of Eros' forced nutation are rather large, due to the fact
that the asteroid has a significant triaxial shape. They are calculated with the
same relative accuracy as the moments of inertia of the asteroid. Our results
are compared with those obtained through numerical integration (Miller et al.
[CITE], Icarus, 155, 3), which show high frequency oscillations of the position
of Eros' axis of figure in space. Some important differences are discussed.
|
Title: |
|
On the composition of ices incorporated in Ceres |
|
Authors: |
|
|
|
Affiliation: |
|
AA(Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland; ), AB(Physikalisches Institut, University of Bern, Sidlerstrasse 5, CH-3012 Bern, Switzerland; ) |
|
Journal: |
|
Monthly Notices of the Royal Astronomical Society, Volume 358, Issue 1, pp. 188-192. (MNRAS Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
MNRAS |
|
Abstract Copyright: |
|
(c) 2005 RAS |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005MNRAS.358..188M |
We use the clathrate hydrate
trapping theory and gas drag formalism to calculate the composition of ices
incorporated in the interior of Ceres. Utilizing a time-dependent solar nebula
model, we show that icy solids can drift from beyond 5 au to the present
location of the asteroid and be preserved from vaporization. We argue that
volatiles were trapped in the outer solar nebula in the form of clathrate
hydrates, hydrates and pure condensates prior to having been incorporated in
icy solids and subsequently in Ceres. Under the assumption that most of
volatiles were not vaporized during the accretion phase and the thermal
evolution of Ceres, we determine the per mass abundances with respect to H2O
of CO2, CO, CH4, N2, NH3, Ar, Xe
and Kr in the interior of the asteroid. The Dawn space mission, scheduled to
explore Ceres in August 2014, may have the capacity to test some predictions.
We also show that an in situ measurement of the D/H ratio in H2O in
Ceres could constrain the distance range in the solar nebula where its icy
planetesimals were produced.
|
Title: |
|
Reanalysis of asteroid families structure through visible spectroscopy |
|
Authors: |
|
|
|
Affiliation: |
|
AA(Observatório Nacional, CAA, Rio de Janeiro, Brazil; Observatoire de Paris/Meudon, LESIA, 5 Place Jules Janssen, Bâtiment 10, 92150 Meudon Cedex, France; ), AB(Observatório Nacional, CAA, Rio de Janeiro, Brazil), AC(Observatório Nacional, CAA, Rio de Janeiro, Brazil; Observatoire de Paris/Meudon, LESIA, 5 Place Jules Janssen, Bâtiment 10, 92150 Meudon Cedex, France) |
|
Journal: |
|
Icarus, Volume 174, Issue 1, p. 54-80. (Icarus Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
ELSEVIER |
|
Keywords: |
|
Asteroids, Spectroscopy |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..174...54M |
The taxonomic properties of the
main asteroid families are analyzed and discussed in the light of an updated
definition of the families using a large proper elements database and the
asteroids taxonomy derived from reflectance spectra recently obtained by two
large visible spectroscopic surveys: the SMASS II and the S3OS2. Our analysis
indicates that most families are quite homogeneous taxonomically and
mineralogically—whenever there exists a mineralogical constraint—, being
probably originated from homogeneous parent bodies. The exceptions are the Nysa
family, that should likely be considered a clan, and
the Eos family that encompasses a broad range of taxonomies, whose
mineralogical relations cannot be completely ruled out. Only in a few cases the
families may be taxonomically distinguished from the background population.
That is the case of the Minerva/Gefion, Adeona, Dora,
Merxia, Hoffmeister, Koronis, Eos, and Veritas families. Some of the families
presented in this work show a larger spectral diversity than previously
reported, as it is the case for the Maria and Koronis families. On the other
hand, the Veritas family is found to be homogeneous, in sharp contrast with
previous works. Mineralogical relations are reported whenever they could be
found in the literature and we examine the possible constraints posed by the
presence of different taxonomies in certain families.
|
Title: |
|
Meteoritic and other constraints on the internal structure and impact history of small asteroids |
|
Authors: |
|
|
|
Affiliation: |
|
Hawai'i Institute of Geophysics and Planetology, |
|
Journal: |
|
Icarus, Volume 174, Issue 1, p. 46-53. (Icarus Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
ELSEVIER |
|
Keywords: |
|
Asteroids, Meteorites, Impact processes, asteroids, Ceres, Eros, Gaspra, Ida, Mathilde, Vesta |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..174...46S |
Studies of the internal structure
of asteroids, which are crucial for understanding their impact history and for
hazard mitigation, appear to be in conflict for the S-type asteroids, Eros,
Gaspra, and Ida. Spacecraft images and geophysical data show that they are
fractured, coherent bodies, whereas models of catastrophic asteroidal impacts,
family and satellite formation, and studies of asteroid spin rates, and other
diverse properties of asteroids and planetary craters suggest that such
asteroids are gravitationally bound aggregates of rubble. These conflicting
views may be reconciled if 10-50 km S-type asteroids formed as rubble piles,
but were later consolidated into coherent bodies. Many meteorites are breccias
that testify to a long history of impact fragmentation and consolidation by
alteration, metamorphism, igneous and impact processes. Ordinary chondrites,
which are the best analogs for S asteroids, are commonly breccias. Some may
have formed in cratering events, but many appear to have formed during
disruption and reaccretion of their parent asteroids. Some breccias were
lithified during metamorphism, and a few were lithified by injected impact
melt, but most are regolith and fragmental breccias that were lithified by mild
or moderate shock, like their lunar analogs. Shock experiments show that porous
chondritic powders can be consolidated during mild shock by small amounts of
silicate melt that glues grains together, and by friction and pressure welding
of silicate and metallic Fe,Ni grains. We suggest that
the same processes that converted impact debris into meteorite breccias also
consolidated asteroidal rubble. Internal voids would be partly filled with
regolith by impact-induced seismic shaking. Consolidation of this material
beneath large craters would lithify asteroidal rubble to form a more coherent
body. Fractures on Ida that were created by antipodal impacts and are
concentrated in and near large craters, and small positive gravity anomalies
associated with the Psyche and Himeros craters on Eros, are consistent with
this concept. Spin data suggest that smaller asteroids 0.6-6 km in size are
unconsolidated rubble piles. C-type asteroids, which are more porous than
S-types, and their analogs, the volatile-rich carbonaceous chondrites, were
probably not lithified by shock.
|
Title: |
|
Space weathering and the low sulfur abundance of Eros |
|
Authors: |
|
|
|
Affiliation: |
|
Center for Space and Planetary Sciences and Department of
Chemistry and Biochemistry, 101 Chemistry Building, University of Arkansas,
Fayetteville, AR 72701, USA. Corresponding author. Current address: |
|
Journal: |
|
Icarus, Volume 174, Issue 1, p. 36-45. (Icarus Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
ELSEVIER |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..174...36K |
The surprisingly low S/Si ratio of
Asteroid 433 Eros measured by the NEAR Shoemaker spacecraft probably reflects a
surface depletion rather than a bulk property of the asteroid. The sulfur X-ray
signal originates at a depth <10 μm in the regolith. The most efficient
process for vaporizing minerals at the heliocentric distance of Eros are sputtering by solar wind ions and hypervelocity impacts.
These are the same processes that account for the changes in optical properties
of asteroids attributed to "space weathering" of lunar surface
materials, although the relative importance of sputtering and impacts need not
be the same for the Moon and asteroids. Troilite, FeS, which is the most
important sulfide mineral in meteorites, and presumably on S-type asteroids
like Eros, can be vaporized by much less energy than other major minerals, and
will therefore be preferentially lost. Within 106 years either
process can remove sulfide from the top 10-100 μm of regolith. Sulfur will be
lost into space and some sulfur will migrate to deeper regolith layers. We also
consider other possible mechanisms of surficial sulfur depletion, such as
mineral segregation in the regolith and perhaps even incipient melting.
Although we consider solar wind sputtering the most likely cause of the sulfur
depletion on Eros, we cannot entirely rule out other processes as causes of the
sulfur deficiency. Laboratory simulations of the relevant processes can address
some of the open questions. Simulations will have to be carried out in such a
way that potential sulfur loss processes as well as resurfacing can be studied
simultaneously, requiring a large and complex environmental chamber.
|
Title: |
|
Spectral alteration of the Meteorite Epinal (H5) induced by heavy ion irradiation: a simulation of space weathering effects on near-Earth asteroids |
|
Authors: |
|
Strazzulla, G.; Dotto, E.; Binzel, R.; Brunetto, R.; Barucci, M. A.; Blanco, A.; Orofino, V. |
|
Affiliation: |
|
AA(INAF—Osservatorio
Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania, Italy; ), AB(INAF—Osservatorio Astronomico di Roma, Italy), AC(Department
of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of
Technology, Cambridge, MA 02139, USA), AD(INAF—Osservatorio Astrofisico di
Catania, Via S. Sofia 78, I-95123 Catania, Italy), AE(LESIA, Observatoire de
Paris, 92195 Meudon Principal Cedex, France), AF(Dipartimento di Fisica,
Università di Lecce, Italy), AG(Dipartimento di Fisica, Università di Lecce,
Italy) |
|
Journal: |
|
Icarus, Volume 174, Issue 1, p. 31-35. (Icarus Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
ELSEVIER |
|
Keywords: |
|
Meteorites, Spectroscopy, Experimental techniques, Radiation chemistry, Asteroid surfaces |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..174...31S |
We present results obtained for
Epinal (H5), an ordinary chondrite meteorite, irradiated with 60 keV Ar++
ions, simulating solar wind heavy particle irradiation. Bidirectional
reflectance spectra (0.3-2.67 μm) measured after irradiating Epinal samples
with different ion fluences exhibit a progressive reddening that is similar to
the spread of spectra observed for S-type near-Earth asteroids. The timescales
for inducing the same effects in space as those obtained in laboratory are
estimated to be 104-106 yr. These results suggest
irradiation by heavy ions may be a very efficient weathering process in
near-Earth space.
|
Title: |
|
Statistical analysis of asteroidal and cometary polarization phase curves |
|
Authors: |
|
Penttilä, A.; Lumme, K.; Hadamcik, E.; Levasseur-Regourd, A.-C. |
|
Affiliation: |
|
AA(Observatory, University of Helsinki, PO Box 14, 00014 University of Helsinki, Finland ), AB(Observatory, University of Helsinki, PO Box 14, 00014 University of Helsinki, Finland), AC(Université Paris VI/Aéronomie CNRS-IPSL, BP 3, 92371 Verrières, France), AD(Université Paris VI/Aéronomie CNRS-IPSL, BP 3, 92371 Verrières, France) |
|
Journal: |
|
Astronomy and Astrophysics, Volume 432, Issue 3, March IV 2005, pp.1081-1090 (A&A Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
EDP |
|
Keywords: |
|
polarization, methods: statistical, techniques: polarimetric, astronomical data bases: miscellaneous, comets: general, minor planets, asteroids |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005A&A...432.1081P |
We use an empirical polarization
phase curve model at various wavelengths to predict some statistical properties
of comets and asteroids. First, we show how our model with Bayesian MCMC
numerical methods predicts polarization behaviour at larger phase angles when
only the smaller angle data are used. Our empirical model incorporates both the
phase and colour dependency on the same footing. Second, a comparison between
the existing taxonomy of asteroids and the clustering of asteroid classes based
on polarization suggests a new method for the classification. We also heavily
concentrate on the derivations of quantitative errors in our analysis.
|
Title: |
|
A study of Cybele asteroids |
|
Authors: |
|
Lagerkvist, C.-I.; Moroz, L.; Nathues, A.; Erikson, A.; Lahulla, F.; Karlsson, O.; Dahlgren, M. |
|
Affiliation: |
|
AA(Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden ), AB(DLR, Optical Information Systems, Rutherfordstrasse 2, 12489 Berlin, Germany), AC(Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Strasse 2, 37191 Katlenburg-Lindau, Germany), AD(DLR, Institute of Planetary Research, Rutherfordstrasse 2, 12489 Berlin, Germany), AE(Observatorio Astronomico, Alfonso XII 3, 28014 Madrid, Spain), AF(Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden), AG(Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden) |
|
Journal: |
|
Astronomy and Astrophysics, Volume 432, Issue 1, March II 2005, pp.349-354 (A&A Homepage) |
|
Publication Date: |
|
03/2005 |
|
Origin: |
|
A&A |
|
Keywords: |
|
minor planets, asteroids |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005A&A...432..349L |
We have used the 3.5 m New
Technology Telescope at ESO, La Silla, to obtain spectra of 18 asteroids
belonging to the Cybele group. One additional Cybele asteroid was observed with
the ESO 3.6 m telescope. From the spectra we have derived spectral slopes and
taxonomy classifications. Our observations show that spectrally red D-type
Cybeles tend to be smaller than more spectrally neutral P- and C-type objects
from this group. Similar colour-diameter trends have previously been reported
for other outer belt low albedo asteroids (Hildas and Trojans). We discuss
possible reasons for this trend. In particular, the observed dominance of red
objects for small diameters is consistent with a space weathering scenario,
where irradiation of asteroid regoliths with solar wind plasma neutralizes
their surface colours due to carbonization of originally reddish organic
components. Collisional disruption of such large greyish "aged"
P-type objects would produce a number of redder D-type fragments lacking mature
regoliths. In addition, the observed colour-diameter trend may be due to
compositional differences between D-, P- and C-type asteroids. P- and C-types
may be lacking at small diameters, since their materials are less susceptible
to collisional break-up than spectrally red D-type material. A simultaneous
contribution of both factors (compositional differences and space weathering)
to the observed trend is possible as well.
Observations were made at the European Southern
Observatory (ESO) with the NTT telescope under program 56.F-0355 and the 3.6 m
telescope under program 62.S-0133.
|
Title: |
|
Negative report of occultation by the D-type asteroid (773) Irmintraud |
|
Authors: |
|
|
|
Journal: |
|
The Observatory, Vol. 125, p. 23-24 |
|
Publication Date: |
|
02/2005 |
|
Origin: |
|
OBS |
|
Bibliographic Code: |
|
2005Obs...125...23C |
Not Available
|
Title: |
|
A closer look at main belt asteroids 1: WF/PC images |
|
Authors: |
|
Storrs, A. D.; Dunne, C.; Conan, J.-M.; Mugnier, L.; Weiss, B. P.; Zellner, B. |
|
Affiliation: |
|
AA(Department of Physics, Astronomy, and Geosciences, Towson University, 8000 York Road, Towson, MD 21252, USA; ), AB(Towson H.S., Cedar Ave., Towson, MD 410-887-3608, USA), AC(ONERA, Département d'Optique Theorique et Appliquee, BP 72, F-92322 Chatillon cedex, France), AD(ONERA, Département d'Optique Theorique et Appliquee, BP 72, F-92322 Chatillon cedex, France), AE(Department of Earth, Atmospheric, and Planetary Sciences, 54-724 Massachusetts Institute of Technology, Cambridge, MA 02139, USA), AF(Department of Physics, GA Southern University, Landrum Box 8031, Statesboro, GA 30460, USA) |
|
Journal: |
|
Icarus, Volume 173, Issue 2, p. 409-416. (Icarus Homepage) |
|
Publication Date: |
|
02/2005 |
|
Origin: |
|
ELSEVIER |
|
Keywords: |
|
Main-belt asteroids, Image processing |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..173..409S |
We present new reconstructions of
images of main belt Asteroids 9 Metis, 18 Melpomene, 19 Fortuna, 216 Kleopatra,
and 624 Hektor, made with the uncorrected Wide-Field/Planetary Camera (WF/PC)
on the Hubble Space Telescope (HST). Deconvolution with the MISTRAL algorithm
demonstrates that these asteroids are clearly resolved. We determine diameters,
albedos, and lower limits to axial ratios for these bodies. We also review the
process used to restore the aberrated images. No surface features or companions
are found, but the rotation of 216 Kleopatra is clearly seen. The asteroidal
albedos are similar to those determined by other procedures.
|
Title: |
|
Thermal infrared (8-13 μm) spectra of 29 asteroids: the Cornell Mid-Infrared Asteroid Spectroscopy (MIDAS) Survey |
|
Authors: |
|
Lim, Lucy F.; McConnochie, Timothy H.; Bell, James F.; Hayward, Thomas L. |
|
Affiliation: |
|
AA(Department of Astronomy, Cornell University, Ithaca, NY 14853, USA; NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA; ), AB(Department of Astronomy, Cornell University, Ithaca, NY 14853, USA), AC(Department of Astronomy, Cornell University, Ithaca, NY 14853, USA), AD(Gemini South Observatory, AURA/Casilla 603, La Serena, Chile) |
|
Journal: |
|
Icarus, Volume 173, Issue 2, p. 385-408. (Icarus Homepage) |
|
Publication Date: |
|
02/2005 |
|
Origin: |
|
ELSEVIER |
|
Keywords: |
|
surfaces, Spectroscopy, Infrared observations, Ceres, Vesta |
|
Abstract Copyright: |
|
Elsevier Inc. |
|
DOI: |
|
|
|
Bibliographic Code: |
|
2005Icar..173..385L |
We report the results of the Cornell
Mid-IR Asteroid Spectroscopy (MIDAS) survey, a program of ground-based
observations designed to characterize the 8-13 μm spectral properties of a
statistically significant sample of asteroids from a wide variety of visible to
near-IR spectral classes. MIDAS is conducted at Palomar Observatory using the
Spectrocam-10 (SC-10) spectrograph on the 200-in Hale telescope. We have
measured the mid-infrared spectra of twenty-nine asteroids and have derived
temperature estimates from our data that are largely consistent with the
predictions of the standard thermal model. We have also generated relative
emissivity spectra for the target asteroids. On only one asteroid, 1 Ceres,
have we found emissivity features with spectral contrast greater than 5%. Our
spectrum of 4 Vesta suggests emissivity variation at the 2-3% level. Published
spectra of several of the small number of asteroids observed with ISO (six of
which are also included in our survey), which appeared to exhibit much stronger
emissivity features, are difficult to reconcile with our measurements.
Laboratory work on mineral and meteorite samples has shown that the contrast of
mid-IR spectral features is greatly reduced at fine grain sizes. Moreover, the
NEAR mission found that 433 Eros is covered by a relatively thick fine-grained
regolith. If small bodies in general possess such regoliths, their mid-IR
spectral features may be quite subtle. This may explain the evident absence of
strong emissivity variation in the majority of the MIDAS spectra.
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Title: |
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Numerical experiments with rubble piles: equilibrium shapes and spins |
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Authors: |
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Richardson, Derek C.; Elankumaran, Pradeep; Sanderson, Robyn E. |
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Affiliation: |
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Department of Astronomy, Computer and Space Sciences Building, Stadium Drive, University of Maryland, College Park, MD 20740-2421, USA. Corresponding author. Fax: +1-301-314-9067.; |
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Journal: |
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Icarus, Volume 173, Issue 2, p. 349-361. (Icarus Homepage) |
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Publication Date: |
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02/2005 |
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Origin: |
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ELSEVIER |
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Keywords: |
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Asteroids, Planetesimals, Rotational dynamics, Solid body tides, Satellites of Jupiter |
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Abstract Copyright: |
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Elsevier Inc. |
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DOI: |
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Bibliographic Code: |
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2005Icar..173..349R |
We present numerical experiments
investigating the shape and spin limits of self-gravitating "perfect"
rubble piles that consist of identical, smooth, rigid, spherical particles with
configurable normal coefficient of restitution and no sliding friction. Such
constructs are currently employed in a variety of investigations, ranging from
the formation of asteroid satellites to the dynamical properties of Saturn's
densest rings. We find that, owing to cannonball stacking behavior, rubble
piles can maintain non-spherical shapes without bulk spin, unlike a fluid, and
can spin faster than a perfect fluid before shedding mass, consistent with the
theory for the more general continuum rubble pile model (Holsapple, 2004,
Icarus 172, 272-303). Rubble piles that reassemble following a catastrophic
disruption reconfigure themselves to lie within stability limits predicted by
the continuum theory. We also find that coarse configurations consisting of a
small number of particles are more resistant to tidal disruption than fine
configurations with many particles. Overall this study shows that idealized
rubble piles behave qualitatively in a manner similar to certain granular
materials, at least in the limit where global shape readjustments and/or mass
shedding begins. The limits obtained here may provide
constraints on the possible internal structure of some small Solar System
bodies that have extreme shapes or are under high stress. Amalthea is presented
as a case study.
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Title: |
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The W isotope composition of eucrite metals: constraints on the timing and cause of the thermal metamorphism of basaltic eucrites |
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Authors: |
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Affiliation: |
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AA(Zentrallabor
für Geochronologie, Institut für Mineralogie, Universität Münster,
Corrensstr. 24, D-48149 Münster, Germany), AB(Zentrallabor für
Geochronologie, Institut für Mineralogie, Universität Münster, Corrensstr.
24, D-48149 Münster, Germany), AC(Institut für Mineralogie und Geochemie,
Universität zu Köln, Zülpicherstr. 49b, D-50476 Köln, Germany),
AD(Zentrallabor für Geochronologie, Institut für Mineralogie, Universität
Münster, Corrensstr. 24, D-48149 Münster, Germany), AE(Zentrallabor für
Geochronologie, Institut für Mineralogie, Universität Münster, Corrensstr. 24,
D-48149 |
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Journal: |
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Earth and Planetary Science Letters, Volume 231, Issue 1-2, p. 41-52. (E&PSL Homepage) |
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Publication Date: |
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02/2005 |
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Origin: |
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ELSEVIER |
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DOI: |
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Bibliographic Code: |
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2005E&PSL.231...41K |
Electronic Article Available from Elsevier Science.
433 Eros -
comparison of lightcurve extrema from 1901-1931 with the present rotation
state Astronomy
and Astrophysics, v.431, p.381-383 (2005) (A&A Homepage) Physical
characteristics of Hayabusa target Asteroid 25143 Itokawa Evidence
for asteroid space weathering from the Sloan Digital Sky Survey Nesvorný, David; Jedicke, Robert; Whiteley, Robert J.; Ivezić, Željko AA(Graduate
School of Science and Technology, Kobe University, 1-1 Rokkodai, Nada, Kobe,
Japan) Earth,
Planets and Space, Volume 57, p. 71-76. (EP&S Homepage) AA(Institute
for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822;
) The
Astronomical Journal, Volume 129, Issue 1, pp. 530-538. (AJ Homepage) Determination
of the mass of (4) Vesta based on new close approaches Astronomy
and Astrophysics, v.430, p.319-325 (2005) (A&A Homepage) Asteroid
target selection for the new Rosetta mission baseline. 21 Lutetia and 2867
Steins Astronomy
and Astrophysics, v.430, p.313-317 (2005) (A&A Homepage) Based on
observations collected at ESO-La Silla, NASA/IRTF and TNG-Canaries. Department
of Astronomy, University of Maryland, College Park, MD 20742, USA.
Corresponding author.; Rivkin, A. S.; Binzel, R. P.; Sunshine, J.; Bus, S. J.; Burbine, T. H.; Saxena, A. Asteroids,
Asteroids near-Earth, Asteroids composition, Meteorites Alvarez-Candal, Alvaro; Duffard, René; Angeli, Cláudia A.; Lazzaro, Daniela; Fernández, Silvia Clark, B. E.; Bus, S. J.; Rivkin, A. S.; Shepard, M. K.; Shah, S. The
Astronomical Journal, Volume 128, Issue 6, pp. 3070-3081. (AJ Homepage)
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