Examinando por Autor "Barbieri, C."

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OSIRIS – The Scientific Camera System Onboard Rosetta
(Springer Link, 2007-01-12) Keller, H. U.; Barbieri, C.; Lamy, Philippe; Rickman, H.; Rodrigo, Rafael; Wenzel, K. P.; Sierks, H.; A´Hearn, M. F.; Angrilli, F.; Angulo, M.; Bailey, M. E.; Barthol, P.; Barucci, M. A.; Bertaux, J. L.; Bianchini, G.; Boit, J. L.; Brown, V.; Burns, J. A.; Büttner, I.; Castro, J. M.; Cremonese, G.; Curdt, W.; Da Deppo, V.; Debei, S.; De Cecco, M.; Dohlen, K.; Fornasier, S.; Fulle, M.; Germerott, D.; Gliem, F.; Guizzo, G. P.; Hviid, S. F.; Ip, W. H.; Jorda, L.; Koschny, D.; kramm, J. R.; Kührt, E.; Küppers, M.; Lara, L. M.; Llebaria, A.; López, A.; López Jiménez, A.; López Moreno, J. J.; Meller, R.; Michalik, H.; Díaz Michelena, M.; Müller, R.; Naletto, G.; Origné, A.; Parzianello, G.; Pertile, M.; Quintana, C.; Ragazzoni, R.; Ramous, P.; Reiche, K. U.; Reina, M.; Rodríguez, J.; Rousset, G.; Sabau, L.; Sivan, J. P.; Stöckner, K.; Telljohann, U.; Thomas, N.; Timón, V.; Tomasch, G.; Wittrock, T.; Zaccariotto, M.; Sanz de la Rosa, Andrea
The Optical, Spectroscopic, and Infrared Remote Imaging System OSIRIS is the scientific camera system onboard the Rosetta spacecraft (Figure 1). The advanced high performance imaging system will be pivotal for the success of the Rosetta mission. OSIRIS will detect 67P/Churyumov-Gerasimenko from a distance of more than 106 km, characterise the comet shape and volume, its rotational state and find a suitable landing spot for Philae, the Rosetta lander. OSIRIS will observe the nucleus, its activity and surroundings down to a scale of ~2 cm px−1. The observations will begin well before the onset of cometary activity and will extend over months until the comet reaches perihelion. During the rendezvous episode of the Rosetta mission, OSIRIS will provide key information about the nature of cometary nuclei and reveal the physics of cometary activity that leads to the gas and dust coma. OSIRIS comprises a high resolution Narrow Angle Camera (NAC) unit and a Wide Angle Camera (WAC) unit accompanied by three electronics boxes. The NAC is designed to obtain high resolution images of the surface of comet 67P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range 250–1000 nm at an angular resolution of 18.6 μrad px−1. The WAC is optimised to provide images of the near-nucleus environment in 14 discrete filters at an angular resolution of 101 μrad px−1. The two units use identical shutter, filter wheel, front door, and detector systems. They are operated by a common Data Processing Unit. The OSIRIS instrument has a total mass of 35 kg and is provided by institutes from six European countries.
Acceso Abierto
Seasonal variations in source regions of the dust jets on comet 67P/Churyumov-Gerasimenko
(EDP Sciences, 2019-09-20) Lai, I. L.; Ip, W. H.; Lee, J. C.; Lin, Z. Y.; Vicent, J. B.; Oklay, N.; Sierks, H.; Barbieri, C.; Lamy, Philippe; Rodrigo, Rafael; Koschny, D.; Rickman, H.; Keller, H. U.; Agarwal, J.; Barucci, M. A.; Bertaux, J. L.; Bertini, I.; Bodewits, D.; Boudreault, S.; Cremonese, G.; Da Deppo, V.; Davidsson, B. J. R.; Debei, S.; De Cecco, M.; Deller, J.; Fornasier, S.; Fulle, M.; Groussin, O.; Gutiérrez, Pedro J.; Güttler, C.; Hofmann, M.; Hviid, S. F.; Jorda, L.; Knollenberg, J.; Kovács, G.; kramm, J. R.; Kührt, E.; Küppers, M.; Lara, L. M.; Lazzarin, M.; López Moreno, J. J.; Marzari, F.; Naletto, G.; Shi, X.; Tubiana, C.; Thomas, N.; Ministry of Science and Technology, Taiwan (MOST)
Aims. We investigate the surface distribution of the source regions of dust jets on comet 67P/Churyumov-Gerasimenko as a function of time. Methods. The dust jet source regions were traced by the comprehensive imaging data set provided by the OSIRIS scientific camera. Results. We show in detail how the projected footpoints of the dust jets and hence the outgassing zone would move in consonance with the sunlit belt. Furthermore, a number of source regions characterized by repeated jet activity might be the result of local topographical variations or compositional heterogeneities. Conclusions. The spatial and temporal variations in source regions of the dust jets are influenced significantly by the seasonal effect. The strong dependence on the solar zenith angle and local time could be related to the gas sublimation process driven by solar insolation on a surface layer of low thermal inertia.
Acceso Abierto
The backscattering ratio of comet 67P/Churyumov–Gerasimenko dust coma as seen by OSIRIS onboard Rosetta
(Oxford Academics: Oxford University Press, 2019-01-22) Bertini, I.; La Forgia, F.; Fulle, M.; Tubiana, C.; Güttler, C.; Moreno, F.; Agarwal, J.; Muñoz, O.; Mottola, S.; Ivanovsky, S.; Pajola, M.; Lucchetti, A.; Petropoulou, V.; Lazzarin, M.; Rotundi, A.; Bodewits, D.; Frattin, E.; Toth, I.; Masoumzadeh, N.; Kovács, G.; Rinaldi, G.; Guirado, D.; Sierks, H.; Naletto, G.; Lamy, Philippe; Rodrigo, Rafael; Koschny, D.; Davidsson, B. J. R.; Barbieri, C.; Barucci, M. A.; Bertaux, J. L.; Cambianica, P.; Cremonese, G.; Da Deppo, V.; Debei, S.; De Cecco, M.; Deller, J.; Ferrari, S.; Ferri, F.; Fornasier, S.; Gutiérrez, Pedro J.; Hasselmann, P. H.; Ip, W. H.; Keller, H. U.; Lara, L. M.; López Moreno, J. J.; Marzari, F.; Massironi, M.; Penasa, L.; Shi, X.; Fulle, M. [0000-0001-8435-5287]; Tubiana, C. [0000-0001-8475-9898]; Güttler, C. [0000-0003-4277-1738]; Pajola, M. [0000-0002-3144-1277]; Rinaldi, G. [0000-0002-2968-0455]; Naletto, G. [0000-0003-2007-3138]; Barucci, M. A. [0000-0002-1345-0890]; Bertaux, J. L. [0000-0003-0333-229X]; Deller, J. [0000-0001-8341-007X]; Fornasier, S. [0000-0001-7678-3310]; Penasa, L. [0000-0002-6394-3108]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Remote sensing observations of dust particles ejected from comets provide important hints on the intimate nature of the materials composing these primitive objects. The measurement of dust coma backscattering ratio, BSR, defined as the ratio of the reflectance at phase angle 0° and 30°, helps tuning theoretical models aimed at solving the inverse scattering problem deriving information on the nature of the ejected particles. The Rosetta/OSIRIS camera sampled the coma phase function of comet 67P, with four series acquired at low phase angles from 2015 January to 2016 May. We also added previously published data to our analysis to increase the temporal resolution of our findings. We measured a BSR in the range ∼ [1.7–3.6], broader than the range found in literature from ground-based observations of other comets. We found that during the post-perihelion phase, the BSR is systematically larger than the classical cometary dust values only for nucleocentric distances smaller than ∼100 km. We explain this trend in terms of a cloud of chunks orbiting the nucleus at distances <100 km ejected during perihelion and slowly collapsing on the nucleus over a few months because of the coma gas drag. This also implies that the threshold particle size for the dust phase function to become similar to the nucleus phase function is between 2.5 mm and 0.1 m, taking into account previous Rosetta findings.
Acceso Abierto
The Rocky‐Like Behavior of Cometary Landslides on 67P/Churyumov‐Gerasimenko
(American Geophysical Union: Advancing Earth and Space Science, 2019-12-18) Lucchetti, A.; Penasa, L.; Pajola, M.; Massironi, M.; Teresa Brunetti, M.; Cremonese, G.; Oklay, N.; Vicent, J. B.; Mottola, S.; Fornasier, S.; Sierks, H.; Naletto, G.; Lamy, Philippe; Rodrigo, Rafael; Koschny, D.; Davidsson, B. J. R.; Barbieri, C.; Antonietta Barucci, M.; Bertaux, J. L.; Bertini, I.; Bodewits, D.; Cambianica, P.; Da Deppo, V.; Debei, S.; De Cecco, M.; Deller, J.; Ferrari, S.; Ferri, F.; Franceschi, M.; Fulle, M.; Gutiérrez, Pedro J.; Güttler, C.; Ip, W. H.; Keller, H. U.; Lara, L.; Lazzarin, M.; López Moreno, J. J.; Marzari, F.; Tubiana, C.; Lucchetti, A. [0000-0001-7413-3058]; Ferrari, S. [0000-0002-0157-3463]; Lara, L. [0000-0002-7184-920X]; Franceschi, M. [0000-0002-2061-0151]; Debei, S. [0000-0002-6757-6616]; Fulle, M. [0000-0001-8435-5287]; López Moreno, J. J. [0000-0002-7946-2624]; Penasa, L. [0000-0002-6394-3108]; Pajola, M. [0000-0002-3144-1277]; Ferri, F. [0000-0003-2395-5275]; Bertini, I. [0000-0002-0616-2444]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Landslides have been identified on several solar system bodies, and different mechanisms have been proposed to explain their runout length. We analyze images from the Rosetta mission and report the global characterization of such features on comet 67P/Churyumov‐Gerasimenko's surface. By assuming the height to runout length as an approximation for the friction coefficient of landslide material, we find that on comet 67P, this ratio falls between 0.50 and 0.97. Such unexpected high values reveal a rocky‐type mechanical behavior that is much more akin to Earth dry landslides than to icy satellites' mass movements. This behavior indicates that 67P and likely comets in general are characterized by consolidated materials possibly rejecting the idea that they are fluffy aggregates. The variability of the runout length among 67P landslides can be attributed to the different volatile content located in the top few meters of the cometary crust, which can drive the mass movement.