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A model of 250 m thick surface shell of a dust-free, porous and icy body similar to a comet, is made to study the effect of vapor flux on temperature, density and abundance distributions of various elements. The components and their distributions in the nucleus are different from those found in coma. It is difficult to estimate the amount of substances which are more volatile than water. The study is of great help in understanding comets.

This report of the business meeting of Commission 15 at the 2009 IAU GA is based on notes provided by Walter Huebner, past president, and on the minutes taken by Daniel Boice, secretary of Commission 15 in the triennium 2006 to 2009, with additional notes from the current secretary, Daniel Hestroffer. The business meeting was split into two sessions, the first held on 5 August and the second held on 11 August. This report presents the minutes of the two Commission 15 business-meeting sessions held during General Assembly XXVII. [ABSTRACT FROM PUBLISHER]

The meeting was opened by Ted Bowell, president, at 11 am. The 2006 Division III meetings were reviewed by Guy Consolmagno, secretary; as the minutes of those meetings have already been published, they were assumed to be approved. [ABSTRACT FROM PUBLISHER]

The meeting was opened by Ted Bowell, president, at 11 am. The 2006 Division III meetings were reviewed by Guy Consolmagno, secretary; as the minutes of those meetings have already been published, they were assumed to be approved. [ABSTRACT FROM PUBLISHER]

This report of the business meeting of Commission 15 at the 2009 IAU GA is based on notes provided by Walter Huebner, past president, and on the minutes taken by Daniel Boice, secretary of Commission 15 in the triennium 2006 to 2009, with additional notes from the current secretary, Daniel Hestroffer. The business meeting was split into two sessions, the first held on 5 August and the second held on 11 August. This report presents the minutes of the two Commission 15 business-meeting sessions held during General Assembly XXVII. [ABSTRACT FROM PUBLISHER]

The Commission 15 report was prepared primarily by the chairpersons of the two working groups: T. Yamamoto of the Comet Working Group and R. A. Gil-Hutton of the Minor Planet Working Group. In particular, the Comet section was produced by T. Yamamoto with the assistance of D. Bockelée-Morvan, H. Kawakita, and D. Prialnik, while the Minor Planet section was produced by R. A. Gil-Hutton with the assistance of A. Cellino, A. W. Harris (DLR), R. Jedicke, A.-C. Levasseur-Regourd, R. M. Schulz, T. B. Spahr, and P. Vernazza. W. F. Huebner was responsible for the Introduction. The final editing and merging of the various sections and subsections of the report was carried out by the Commission Secretary, D. C. Boice. [ABSTRACT FROM PUBLISHER]

Division III's activities focus on a broad range of astronomical research on bodies in the solar system (excluding the Sun), on extrasolar planets, and on the search for life in the Universe. [ABSTRACT FROM PUBLISHER]

The report of Commission 15 was prepared primarily by the chairpersons of its two working groups: the Minor Planet Working Group and the Comet Working Group. In particular, the Minor Planet section was created by A. Cellino with a little help from E. Tedesco and the Comet section by T. Yamamoto with the assistance of D. Bockelée-Morvan, W. Huebner, A. Bhardwaj, D. Biesecker, L. Jorda, H. Kawakita, H. U. Keller, H. Kimura, A. Kouchi, and D. Prialnik. E. Tedesco was responsible for the Introduction, final editing, and merging of the two reports. [ABSTRACT FROM PUBLISHER]

Comet simulation experiments are discussed, in the context of physical models and the results in cometary physics, gathered especially from the GIOTTO space mission to comet P'Halley. The “status of the today knowledge” about comets, the experiments could start from, is briefly reviewed. The setup of the KOSI (German = Kometen Simulation) - experiments and the techniques to produce cometary analogous material, on the basis of that knowledge are described in general, as for the different KOSI experiments. The limitations of the simulation of physical processes at the surface of real comets in an earth-bound laboratory are discussed, and the possibilities to receive common insights in cometary physics are shown. Methods and procedures are described, and the major results reviewed. As with attempting to reproduce any natural phenomenon in the laboratory, there are short-comings to these experiments, but there are possibly major new insights to be gained. Physical laws only have the same consequences under same experimental or environmental conditions. A number of small-scale comet simulation experiments have been performed, since the early 60ties in many laboratories, but the largest and most ambitious series of comet simulation experiments to date were performed between 1987 and 1993 using the German space agency's (DLR) space hardware testing facilities in Cologne. These experiments were triggered by the scientific community after the comet P'Halley's recurrence in 1986 and the many data gathered by the space missions in this year. Simulation experiments have proved valuable in developing methods for making cometary analogues, and for exploring specific properties of such materials in detail. These experiments provided new insights into the morphology and physical behavior of aggregates formed out of silicate- /water-ice -grains likely to exist in comets. The formation of a dust mantle on the surface, and a system of ice layers below the mantle from the different admixed materials, have been detected after the insolation of the artificial comet. The mechanisms for heat transfer between the comet's surface and its interior, compositional, structural, and isotopic changes that occur near the comet's surface, were described by modeling in accordance with the experimental results. The mechanisms of the ejection of dust and ice grains from the surface, and the importance of gas-drag in propelling grains were investigated by close-up video cameras. [ABSTRACT FROM AUTHOR]

This report of the business meeting at the 2006 IAU GA is based on notes provided by Edward Tedesco, past president, and on the minutes taken by Petrus Jenniskens, secretary of Commission 15 in the triennium 2003 to 2006, with additional notes from the current secretary of Commission 15, Daniel Boice. For political reasons the incoming President, Walter Huebner, was unable to attend the General Assembly. [ABSTRACT FROM PUBLISHER]

The meeting of the Physical Properties of the Minor Planets Working Group of IAU Commission 15 took place on 24 August, and was devoted to purely scientific matters, since other topics (organization of the Minor Planet WG, need of a new web page, election of the new chairman) had been already discussed during the business meeting of Commission 15, on 22 August. A brief summary of the talks given during the meeting is given in what follows. [ABSTRACT FROM PUBLISHER]

Profiles Jurgen H. Rahe, science program director for solar system exploration in National Aeronautics and Space Administration's (NASA) Office of Space Science who died on June 18, 1997. Cause of his death; His educational background and contributions to planetary science; His publications about comets; Achievements.

Abstract: The NEAR Shoemaker mission to near-Earth asteroid 433 Eros provided a great deal of information about the asteroid. Still to be learned are the interior structure and material properties: the local density, strength, and cohesiveness within Eros. Seismology is a way to determine such information. This paper numerically explores performing a seismological experiment on Eros, using an explosive as a seismic source. Computations with the explosive source were performed in an Eulerian hydrocode (CTH) and then results of those computations were transferred to a Lagrangian wavecode (LS-DYNA) to calculate the subsequent seismic wave propagation in the body. To verify the technique, computations were first carried out for two cases where analytical results are known: a uniaxial-strain bar and a sphere. Computations were then performed for a three-dimensional solid model of Eros with surface shape based on NEAR data. Initial computations assumed Eros was isotropic and homogeneous in its material properties. Modal frequency computations for the isotropic, homogeneous Eros were then compared with a model of Eros that included an interior fracture plane. Differences in seismic traces and in modal frequencies show that seismology can differentiate the interior of Eros in particular and other asteroids in general. [Copyright &y& Elsevier]