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  2009 Leonard Medal for Lawrence Grossman

  Humayun, Munir (The Meteoritical Society, 2009-01-01)
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  2009 Barringer Medal for Wolf Uwe Reimold

  Koeberl, Christian (The Meteoritical Society, 2009-01-01)
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  Insight from the unexpected

  Bradley, J. P.; Jones, A. P.; Brownlee, D. E. (The Meteoritical Society, 2009-01-01)

  The NASA Stardust mission returned samples from comet 81P/Wild 2, an active Jupiter-family comet that is believed to have formed at a heliocentric distance beyond the orbit of Neptune. The study of the samples has provided a critical first look at the micrometer and larger solid materials that were at the edge of the solar system at the time that Kuiper Belt comets formed. Analysis of the samples has involved a number of challenges and surprises. These issues and the full implications of the information that the samples provide were intently discussed at the Timber Cove II meeting October 2628, 2008. The meeting was sponsored by the Institute of Geophysics and Planetary Physics (IGPP) and it was held at a ruggedly beautiful and remote location on the Sonoma coast of northern California once protected by a Russian fort. Seventeen of the papers presented at the meeting are presented in this volume.
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  2009 Service Award for Derek Sears

  Drake, Michael J. (The Meteoritical Society, 2009-01-01)
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  Abstracts for the 72nd Annual Meeting of the Meteoritical Society

  The Meteoritical Society, 2009-01-01
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  A meteorite crater on Earth formed on September 15, 2007: The Carancas hypervelocity impact

  Tancredi, G.; Ishitsuka, J.; Schultz, P. H.; Harris, R. S.; Brown, P.; ReVelle, D. O.; Antier, K.; Le Pichon, A.; Rosales, D.; Vidal, E.; et al. (The Meteoritical Society, 2009-01-01)

  On September 15, 2007, a bright fireball was observed and a big explosion was heard by many inhabitants near the southern shore of Lake Titicaca. In the community of Carancas (Peru), a 13.5 m crater and several fragments of a stony meteorite were found close to the site of the impact. The Carancas event is the first impact crater whose formation was directly observed by several witnesses as well as the first unambiguous seismic recording of a crater-forming meteorite impact on Earth. We present several lines of evidence that suggest that the Carancas crater was a hypervelocity impact. An event like this should have not occurred according to the accepted picture of stony meteoroids ablating in the Earths atmosphere, therefore it challenges our present models of entry dynamics. We discuss alternatives to explain this particular event. This emphasizes the weakness in the pervasive use of average parameters (such as tensile strength, fragmentation behavior and ablation behavior) in current modeling efforts. This underscores the need to examine a full range of possible values for these parameters when drawing general conclusions from models about impact processes.
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  Experimental study on the collisional disruption of porous gypsum spheres

  Okamoto, C.; Arakawa, M. (The Meteoritical Society, 2009-01-01)

  In order to study the catastrophic disruption of porous bodies such as asteroids and planetesimals, we conducted several impact experiments using porous gypsum spheres (porosity: 50%). We investigated the fragment mass and velocity of disrupted gypsum spheres over a wide range of specific energies from 3 x 10^3 J/kg to 5 x 10^4 J/kg. We compared the largest fragment mass (ml/Mt) and the antipodal velocity (Va) of gypsum with those of non-porous materials such as basalt and ice. The results showed that the impact strength of gypsum was notably higher than that of the non-porous bodies; however, the fragment velocity of gypsum was slower than that of the non-porous bodies. This was because the micro-pores dispersed in the gypsum spheres caused a rapid attenuation of shock pressure in them. From these results, we expect that the collisional disruption of porous bodies could be significantly different from that of non-porous bodies.
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  Simultaneous spectroscopic and photometric observations of binary asteroids

  Polishook, D.; Brosch, N.; Prialnik, D.; Kaspi, S. (The Meteoritical Society, 2009-01-01)

  We present results of visible wavelengths spectroscopic measurements (0.45 to 0.72 microns) of two binary asteroids, obtained with the 1-m telescope at the Wise Observatory on January 2008. The asteroids 90 Antiope and 1509 Esclangona were observed to search for spectroscopic variations correlated with their rotation while presenting different regions of their surface to the viewer. Simultaneous photometric observations were performed with the Wise Observatorys 0.46 m telescope, to investigate the rotational phase behavior and possible eclipse events. 90 Antiope displayed an eclipse event during our observations. We could not measure any slope change of the spectroscopic albedo within the error range of 3%, except for a steady decrease in the total light flux while the eclipse took place. We conclude that the surface compositions of the two components do not differ dramatically, implying a common origin and history. 1509 Esclangona did not show an eclipse, but rather a unique lightcurve with three peaks and a wide and flat minimum, repeating with a period of 3.2524 hours. Careful measurements of the spectral albedo slopes reveal a color variation of 7 to 10 percent on the surface of 1509 Esclangona, which correlates with a specific region in the photometric lightcurve. This result suggests that the different features on the lightcurve are at least partially produced by color variations and could perhaps be explained by the existence of an exposed fresh surface on 1509 Esclangona.
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  Author Index

  The Meteoritical Society, 2009-01-01
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  Composition of 298 Baptistina: Implications for the K/T impactor link

  Reddy, V.; Emery, J. P.; Gaffey, M. J.; Bottke, W. F.; Cramer, A.; Kelley, M. S. (The Meteoritical Society, 2009-01-01)

  Bottke et al. (2007) suggested that the breakup of the Baptistina asteroid family (BAF) 160+30 /-20 Myr ago produced an asteroid shower that increased by a factor of 2-3 the impact flux of kilometer-sized and larger asteroids striking the Earth over the last ~120 Myr. This result led them to propose that the impactor that produced the Cretaceous/Tertiary (K/T) mass extinction event 65 Myr ago also may have come from the BAF. This putative link was based both on collisional/dynamical modeling work and on physical evidence. For the latter, the available broadband color and spectroscopic data on BAF members indicate many are likely to be dark, low albedo asteroids. This is consistent with the carbonaceous chondrite-like nature of a 65 Myr old fossil meteorite (Kyte 1998)and with chromium from K/T boundary sediments with an isotopic signature similar to that from CM2 carbonaceous chondrites. To test elements of this scenario, we obtained near-IR and thermal IR spectroscopic data of asteroid 298 Baptistina using the NASA IRTF in order to determine surface mineralogy and estimate its albedo. We found that the asteroid has moderately strong absorption features due to the presence of olivine and pyroxene, and a moderately high albedo (~20%). These combined properties strongly suggest that the asteroid is more like an S-type rather than Xc-type (Moth-Diniz et al. 2005). This weakens the case for 298 Baptistina being a CM2 carbonaceous chondrite and its link to the K/T impactor. We also observed several bright (V Mag. 16.8) BAF members to determine their composition.
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  Asteroid photometric and polarimetric phase curves: Joint linear-exponential modeling

  Muinonen, K.; Penttilä, A.; Cellino, A.; Belskaya, I. N.; Delbò, M.; Levasseur-Regourd, A. C.; Tedesco, E. F. (The Meteoritical Society, 2009-01-01)

  We present Markov-Chain Monte-Carlo methods (MCMC) for the derivation of empirical model parameters for photometric and polarimetric phase curves of asteroids. Here we model the two phase curves jointly at phase angles approximately <25 degrees using a linear-exponential model, accounting for the opposition effect in disk-integrated brightness and the negative branch in the degree of linear polarization. We apply the MCMC methods to V-band phase curves of asteroids 419 Aurelia (taxonomic class F), 24 Themis (C), 1 Ceres (G), 20 Massalia (S), 55 Pandora (M), and 64 Angelina (E). We show that the photometric and polarimetric phase curves can be described using a common nonlinear parameter for the angular widths of the opposition effect and negative-polarization branch, thus supporting the hypothesis of common physical mechanisms being responsible for the phenomena. Furthermore, incorporating polarimetric observations removes the indeterminacy of the opposition effect for 1 Ceres. We unveil a trend in the interrelation between the enhancement factor of the opposition effect and the angular width: the enhancement factor decreases with decreasing angular width. The minimum polarization and the polarimetric slope at the inversion angle show systematic trends when plotted against the angular width and the normalized photometric slope parameter. Our new approach allows improved analyses of possible similarities and differences among asteroidal surfaces.
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  From KBOs to Centaurs: The thermal connection

  Sarid, G.; Prialnik, D. (The Meteoritical Society, 2009-01-01)

  We present results of thermal evolution calculations for objects originating in the Kuiper belt and transferring inwards, to the region of the outer planets. Kuiper belt objects (KBOs) are considered to be part of a reservoir that supplies the flux of small icy bodies, mainly Centaurs and Jupiter-family comets, to regions interior to the orbit of Neptune. We study the internal thermal evolution, for ~10^8 yr, of three typical KBOs and use the end state of the simulation as initial conditions for evolutionary calculations of two typical Centaurs. Some evolutionary trends can be identified for the KBOs, depending on key physical parameters, such as size and composition. The subsequent evolution in the Centaur region results in both specific features for each modeled object (mainly surface and sub-surface composition) and common characteristics of thermally evolved Centaurs.
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  The impact origin of Eunomia and Themis families

  Leliwa-Kopystyński, J.; Burchell, M. J.; Włodarczyk, I. (The Meteoritical Society, 2009-01-01)

  Criteria for finding asteroid families (Zappala et al. 1995) are applied to a large (205,770 member) data set of asteroid orbital elements. The cases of the Eunomia and Themis families are considered as examples. This is combined with the cratering criteria for catastrophic disruption of small bodies in the solar system (Leliwa-Kopystyński et al. 2008). We find that the Eunomia parent body itself was not catastrophically disrupted in the family-generating impact event; after impact, the current body contains as much as 70% of its primordial mass. However, by contrast with Eunomia, the present mass of 24 Themis is only about 21% of that of its primordial body. Limits are placed on the sizes of the impactors in both examples, and for the case of Eunomia, the radius of the just sub-critical crater (which may be present on 15 Eunomia) is predicted as 58 km.
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  KLENOT Project 2002-2008 contribution to NEO astrometric follow-up

  Ticha, J.; Tichy, M.; Kocer, M.; Honkova, M. (The Meteoritical Society, 2009-01-01)

  Near-Earth object (NEO) research plays an increasingly important role not only in solar system science but also in protecting our planetary environment as well as human society from the asteroid and comet hazard. Consequently, interest in detecting, tracking, cataloguing, and the physical characterizing of these bodies has steadily grown. The discovery rate of current NEO surveys reflects progressive improvement in a number of technical areas. An integral part of NEO discovery is astrometric follow-up crucial for precise orbit computation and for the reasonable judging of future close encounters with the Earth, including possible impact solutions. The KLENOT Project of the Klet Observatory (South Bohemia, Czech Republic) is aimed especially at the confirmation, early follow-up, long-arc follow-up, and recovery of near-Earth objects. It ranks among the worlds most prolific professional NEO follow-up programs. The 1.06 m KLENOT telescope, put into regular operation in 2002, is the largest telescope in Europe used exclusively for observations of minor planets and comets, and full observing time is dedicated to the KLENOT team. In this paper, we present the equipment, technology, software, observing strategy, and results of the KLENOT Project obtained during its first phase from March 2002 to September 2008. The results consist of thousands of precise astrometric measurements of NEOs and also three newly discovered near-Earth asteroids. Finally, we also discuss future plans reflecting also the role of astrometric follow-up in connection with the modus operandi of the next generation surveys.
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  The formation of the Baptistina family by catastrophic disruption: Porous versus non-porous parent body

  Jutzi, M.; Michel, P.; Benz, W.; Richardson, D. C. (The Meteoritical Society, 2009-01-01)

  In this paper, we present numerical simulations aimed at reproducing the Baptistina family based on its properties estimated by observations. A previous study by Bottke et al. (2007) indicated that this family is probably at the origin of the K/T impactor, is linked to the CM meteorites and was produced by the disruption of a parent body 170 km in size due to the head-on impact of a projectile 60 km in size at 3 km s^(-1). This estimate was based on simulations of fragmentation of non-porous materials, while the family was assumed to be of degrees C taxonomic type, which is generally interpreted as being formed from a porous body. Using both a model of fragmentation of non-porous materials, and a model that we developed recently for porous ones, we performed numerical simulations of disruptions aimed at reproducing this family and at analyzing the differences in the outcome between those two models. Our results show that a reasonable match to the estimated size distribution of the real family is produced from the disruption of a porous parent body by the head-on impact of a projectile 54 km in size at 3 km s^(-1). Thus, our simulations with a model consistent with the assumed dark type of the family requires a smaller projectile than previously estimated, but the difference remains small enough to not affect the proposed scenario of this family history. We then find that the break-up of a porous body leads to different outcomes than the disruption of a non-porous one. The real properties of the Baptistina family still contain large uncertainties, and it remains possible that its formation did not involve the proposed impact conditions. However, the simulations presented here already show some range of outcomes and once the real properties are better constrained, it will be easy to check whether one of them provides a good match.
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  Dynamical constraints on the origin of Main Belt comets

  Haghighipour, N. (The Meteoritical Society, 2009-01-01)

  In an effort to understand the origin of Main Belt comets (MBCs) 7968 Elst-Pizzaro, 118401, and P/2005 U1, the dynamics of these three icy asteroids and a large number of hypothetical MBCs were studied. Results of extensive numerical integrations of these objects suggest that they were formed in place through the collisional breakup of a larger precursor body. Simulations point specifically to the Themis family of asteroids as the origin of these objects and rule out the possibility of a cometary origin (i.e., inward scattering of comets from outer solar system and their primordial capture in the asteroid belt). Results also indicate that while 7968 Elst-Pizzaro and 118401 maintain their orbits for 1 Gyr, P/2005 U1 diffuses chaotically in eccentricity and becomes unstable in ~20 Myr. The latter suggest that this MBC used to be a member of the Themis family and is now escaping away. Numerical integrations of the orbits of hypothetical MBCs in the vicinity of the Themis family show a clustering of stable orbits (with eccentricities smaller than 0.2 and inclinations less than 25) suggesting that many more MBCs may exist in the vicinity of this family (although they might have not been activated yet). The details of the results of simulations and the constraints on the models of the formation and origins of MBCs are presented and their implications for the detection of more of these objects are discussed.
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  Estimating the number of impact flashes visible on the Moon from an orbiting camera

  Koschny, D.; McAuliffe, J. (The Meteoritical Society, 2009-01-01)

  Using a dust flux model and experimental data on the efficiency of light emission upon impact, the number of impact flashes visible on the Moon by a camera on a lunar orbiter is estimated.
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  Asteroid orbital ranging using Markov-Chain Monte Carlo

  Oszkiewicz, D.; Muinonen, K.; Virtanen, J.; Granvik, M. (The Meteoritical Society, 2009-01-01)

  We present a novel Markov-Chain Monte-Carlo orbital ranging method (MCMC) for poorly observed single-apparition asteroids with two or more observations. We examine the Bayesian a posteriori probability density of the orbital elements using methods that map a volume of orbits in the orbital-element phase space. In particular, we use the MCMC method to sample the phase space in an unbiased way. We study the speed of convergence and also the efficiency of the new method for the initial orbit computation problem. We present the results of the MCMC ranging method applied to three objects from different dynamical groups. We conclude that the method is applicable to initial orbit computation for near-Earth, main-belt, and transneptunian objects.
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  OpenOrb: Open-source asteroid orbit computation software including statistical ranging

  Granvik, M.; Virtanen, J.; Oszkiewicz, D.; Muinonen, K. (The Meteoritical Society, 2009-01-01)

  We are making an open-source asteroid orbit computation software package called OpenOrb publicly available. OpenOrb is built on a well-established Bayesian inversion theory, which means that it is to a large part complementary to orbit-computation packages currently available. In particular, OpenOrb is the first package that contains tools for rigorously estimating the uncertainties resulting from the inverse problem of computing orbital elements using scarce astrometry. In addition to the well-known least-squares method, OpenOrb also contains both Monte-Carlo (MC) and Markov-Chain MC (MCMC; Oszkiewicz et al. [2009]) versions of the statistical ranging method. Ranging allows the user to obtain sampled, non-Gaussian orbital-element probability-density functions and is therefore optimized for cases where the amount of astrometry is scarce or spans a relatively short time interval. Ranging-based methods have successfully been applied to a variety of different problems such as rigorous ephemeris prediction, orbital element distribution studies for transneptunian objects, the computation of invariant collision probabilities between near-Earth objects and the Earth, detection of linkages between astrometric asteroid observations within an apparition as well as between apparitions, and in the rigorous analysis of the impact of orbital arc length and/or astrometric uncertainty on the uncertainty of the resulting orbits. Tools for making ephemeris predictions and for classifying objects based on their orbits are also available in OpenOrb. As an example, we use OpenOrb in the search for candidate retrograde and/or high-inclination objects similar to 2008 KV42 in the known population of transneptunian objects that have an observational time span shorter than 30 days.
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  Absolute magnitude and slope parameter G calibration of asteroid 25143 Itokawa

  Bernardi, F.; Micheli, M.; Tholen, D. J. (The Meteoritical Society, 2009-01-01)

  We present results from an observing campaign of 25143 Itokawa performed with the 2.2 m telescope of the University of Hawaii between November 2000 and September 2001. The main goal of this paper is to determine the absolute magnitude H and the slope parameter G of the phase function with high accuracy for use in determining the geometric albedo of Itokawa. We found a value of H = 19.40 and a value of G = 0.21.

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