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Nathan Kaib (University of Oklahoma)17/05/2016 10:15The Oort cloud has previously been invoked to explain observations of centaurs with very high inclinations and/or very large semimajor axes since such orbits are difficult to generate from the scattered disk. However, the known sample of centaurs has been detected with a combination of surveys with different observational biases, some more well-characterized than others. Consequently, it is...Aller à la page de la contribution
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Prof. Vacheslav Emel'yanenko (Institute of Astronomy, RAS)17/05/2016 11:00We discuss how many comets come to short-period orbits from different sources in the outer solar system. The observed distribution of Centaurs, as a transition population, plays a pivotal role in constraining our models. We show that the Oort cloud and the scattered disc produce similar numbers of Jupiter-family comets.Aller à la page de la contribution
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Dr Piotr A. Dybczyński (Astronomical Observatory Institute, faculty of physics, A.Mickiewicz Univ., Poznań, Poland)17/05/2016 14:00Galactic and stellar perturbations are important factors when studying the past and future motion of the observed Oort spike comets. Since our knowledge on the Solar System Galactic environment is continuously increasing it is necessary to upgrade our methods and computer codes for taking into account these perturbations in a proper way. I will report our preparations to incorporate new...Aller à la page de la contribution
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Małgorzata Królikowska (SRC PAS)17/05/2016 14:45Currently, this Catalogue includes orbits of about 160 Oort spike comets defined as objects with original 1/a less than 0.000100 au$^{-1}$. Orbits were determined or redetermined in a completely homogeneous way and constitute more than 85% of the Oort spike comets discovered before 2010. In the publicly available Catalogue, we offer observed (i.e. osculating orbit at the epoch close to the...Aller à la page de la contribution
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Dr Brasser Ramon (Institute for Astronomy and Astrophysics, Taiwan)17/05/2016 16:00I discuss how the proposed instability of the giant planets that sculpted the Kuiper Belt and Scattered Disc also formed the Oort comet cloud. I show the results of numerical simulations of this problem and discuss formation efficiency, number of comets in the cloud and the Oort cloud to Scattered Disc population ratios. I compare these with observations and give an updated estimate based...Aller à la page de la contribution
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Hans Rickman (Uppsala University)17/05/2016 16:45Solar type stars typically form as members of embedded clusters, which dissolve on different time scales depending on their masses and densities. Most such clusters are small and short-lived, and Oort Cloud (OC) formation has often been modeled within such a scenario. But Lada & Lada (2003) showed that about equal numbers of stars are formed in clusters with populations of 10^2, 10^3 and 10^4...Aller à la page de la contribution
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Marc Fouchard18/05/2016 09:15We will present our last results on the long term dynamics of the Oort cloud comets. It particular the final shape of the Oort cloud and its dependency on the initial condition sample will be investigated. The relations between the final shape and present flux of observable "new" long period comets are also highlighted.Aller à la page de la contribution
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Giovanni Valsecchi (IAPS-INAF)18/05/2016 10:00Close encounters with the giant planets play an important role in the evolution of the orbits of long period comets, and have been treated in a number of papers. We revisit the subject in the framework of an analytic theory of close encounters, that provides useful insight on the properties of the strong perturbations caused by planetary encounters.Aller à la page de la contribution
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Prof. Rudolf Dvorak (Universite de Vienne, Autriche)18/05/2016 11:15We investigate whether there can exist comet families in the extrasolar planetary systems Kepler 90 and HD 10180, systems which consist of six planets; the outermost is a giant. This is done by extensive numerical integrations of millions of hypothetical comets entering the inner system on almost hyperbolic orbits. The goal is to find whether families like the Halley comets or the Jupiter...Aller à la page de la contribution
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Dr alessandro morbidelli (OCA)18/05/2016 12:00Comets are often thought of as "pristine planetesimals". However, most cometary objects that we study are just a few km in size. Planetesimals this small are highly unlikely to be pristine planetesimals. In fact, the collisional environment in the trans-Neptunian planetesimal disk was very severe both before and during the giant planet instability phase that formed and sculpted the current...Aller à la page de la contribution
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Dr Bjorn Davidsson (Uppsala university)18/05/2016 14:15For decades, comet scientists have debated whether comet nuclei are primordial rubble piles, formed at their current sizes through gentle accretion in the Solar Nebula, or if they are collisional rubble piles formed in the aftermath of violent collisions between larger parent bodies. The Rosetta mission to comet 67P/Churyumov-Gerasimenko and the Stardust sample-return mission to comet...Aller à la page de la contribution
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Nicolas Biver18/05/2016 15:00For the last 3 decades, infrared and especially microwave techniques have enabled the detection of up to 26 different parent molecules in the coma of comets. Several molecules have been detected in over 40 different comets. A large diversity of composition is seen in the sample, comprising comets of various dynamical origin. Abundances relative to water for the molecules can vary by a...Aller à la page de la contribution
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Maria Antonietta Barucci (LESIA - Paris Observatory)18/05/2016 16:15The study of the small bodies that orbit the Sun beyond Neptune, the transneptunian objects, has completely changed our view of the Solar System. The last decade, a huge quantity of data has been obtained by ground large telescopes and by space missions. Various surface compounds have been detected, including ices of water, methane, nitrogen, methanol, ethane and ammonia. An overview for all...Aller à la page de la contribution
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Slawomira Szutowicz (Space Research Centre)18/05/2016 17:00In comets the anisotropic gas emission from their nuclei have been discovered in gas jets, fans, close-up images of cometary nuclei provided by missions, asymmetric shapes of the cometary gas production curves with respect to perihelion, asymmetric non-gravitational forces perturbing the cometary orbits and finally in the spectral imaging of comets in the molecular lines. The evidence of...Aller à la page de la contribution
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Marcello Fulchignoni19/05/2016 09:15
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Holger Sierks (Max planck Institute, Gottingen, Germany)19/05/2016 10:00Comets with their coma and tail are a spectacular sight on the night sky; they are important objects to understand the origin of our solar system. Comets are pristine and thus carry information on how they initially formed 4.5 billion years ago. 67P/Churyumov-Gerasimenko is the first comet studied in detail with a spacecraft in its vicinity for more than two years along the orbit around the...Aller à la page de la contribution
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Prof. Dominique Bockelée-Morvan (LESIA)19/05/2016 11:15Cometary activity involves complex processes, which are related to the thermal history of the comet nucleus and evolutionary effects, and depend on the nature and properties of surface and subsuface material. Whereas ground-based observations provided insights on the volatiles responsible for cometary activity and showed evidence for non-uniform activity and seasonnal effects, a thorough...Aller à la page de la contribution
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Fabrizio Capaccioni (IAPS-INAF)19/05/2016 12:00The paper will describe the major results obtained so far by the Visible, Infrared and Thermal Imaging Spectrometer (VIRTIS), the dual channel spectrometer onboard Rosetta, on the surface composition and physical properties of the nucleus of comet 67P/Churyumov-Gerasimenko and the implications on the origin and evolution of the nucleus. These results were achieved studying the reflected and...Aller à la page de la contribution
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Dr Cécile Engrand (C.S.N.S.M.)19/05/2016 14:15The composition of cometary dust has been measured by in situ and remote sensing instruments in the last decades, each analysis adding pieces to the puzzle of how and where comets formed. Giotto analyses of comet 1P/Halley dust particles have shown the presence of CHON and mixed particles. Astronomical observations showed that olivine and pyroxene are present in comets. Laboratory analyses of...Aller à la page de la contribution
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Laurent Jorda (LAM)19/05/2016 15:00Will be submitted soonAller à la page de la contribution
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Dr Elena Lega (OCA)19/05/2016 16:15On the basis of backward numerical integrations of a large set of simulated comets whose initial conditions were obtained from small variations of the orbital parameters of comet 67P, and using the analysis of suitable chaos indicators, we detect the phase--space structure of the past close encounters of the comet with Jupiter. On the basis of these computations we find that the probability...Aller à la page de la contribution
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Hans Rickman (PAS Space Research Center, Warszawa, Poland)19/05/2016 17:00We have simulated the orbital evolution of icy planetesimals ("comets") in the inner solar system upon dispersal of the primordial planetesimal disk by giant planet migration as prescribed by the Nice Model. Using both the assumption of non-evolving comets and models including erosion by sublimation and splitting, we have estimated the impact rate and crater formation due to these comets on...Aller à la page de la contribution
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