ALBERT

Description: By using the images acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) and ROLIS (ROsetta Lander Imaging System) cameras, we derive the size–frequency distribution (SFD) of cometary pebbles and boulders covering the size range 0.05–30.0 m on the Agilkia landing site. The global SFD measured on OSIRIS images, reflects the different properties of the multiple morphological units present on Agilkia, combined with selection effects related to lifting, transport and redeposition. Contrarily, the different ROLIS SFD derived on the smooth and rough units may be related to their different regolith thickness present on Agilkia. In the thicker, smoother layer, ROLIS mainly measures the SFD of the airfall population which almost completely obliterates the signature of underlying boulders up to a size of the order of 1 m. This is well matched by the power-law index derived analysing coma particles identified by the grain analyser Grain Impact Analyser and Dust Accumulator. This result confirms the important blanketing dynamism of Agilkia. The steeper SFD observed in rough terrains from 0.4 to 2 m could point out intrinsic differences between northern and southern dust size distributions, or it may suggest that the underlying boulders ‘peek through’ the thinner airfall layer in the rough terrain, thereby producing the observed excess in the decimetre size range. Eventually, the OSIRIS SFD performed on the Philae landing unit may be due to water sublimation from a static population of boulders, affecting smaller boulders before the bigger ones, thus shallowing the original SFD.

Description: Our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the Khonsu region on the comet 67P/Churyumov–Gerasimenko. Despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. It is noticeable that the smooth areas in Khonsu possess similar spectrophotometric behaviour to some other regions of the comet. We observed bright patches on Khonsu with an estimation of 〉40 per cent of normal albedo and suggest that they are associated with H 2 O ice. One of the studied bright patches has been observed to exist on the surface for more than 5 months without a major decay of its size, implying the existence of potential sub-surface icy layers. Its location may be correlated with a cometary outburst during the perihelion passage of the comet in 2015 August, and we interpret it to have triggered the surface modifications necessary to unearth the stratified icy layers beneath the surface. A boulder analysis on Khonsu leads to a power-law index of –3.1 +0.2/–0.3 suggesting a boulder formation, shaped by varying geological processes for different morphological units.

Description: The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.

Description: Pits have been observed on many cometary nuclei mapped by spacecraft. It has been argued that cometary pits are a signature of endogenic activity, rather than impact craters such as those on planetary and asteroid surfaces. Impact experiments and models cannot reproduce the shapes of most of the observed cometary pits, and the predicted collision rates imply that few of the pits are related to impacts. Alternative mechanisms like explosive activity have been suggested, but the driving process remains unknown. Here we report that pits on comet 67P/Churyumov-Gerasimenko are active, and probably created by a sinkhole process, possibly accompanied by outbursts. We argue that after formation, pits expand slowly in diameter, owing to sublimation-driven retreat of the walls. Therefore, pits characterize how eroded the surface is: a fresh cometary surface will have a ragged structure with many pits, while an evolved surface will look smoother. The size and spatial distribution of pits imply that large heterogeneities exist in the physical, structural or compositional properties of the first few hundred metres below the current nucleus surface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vincent, Jean-Baptiste -- Bodewits, Dennis -- Besse, Sebastien -- Sierks, Holger -- Barbieri, Cesare -- Lamy, Philippe -- Rodrigo, Rafael -- Koschny, Detlef -- Rickman, Hans -- Keller, Horst Uwe -- Agarwal, Jessica -- A'Hearn, Michael F -- Auger, Anne-Therese -- Barucci, M Antonella -- Bertaux, Jean-Loup -- Bertini, Ivano -- Capanna, Claire -- Cremonese, Gabriele -- Da Deppo, Vania -- Davidsson, Bjorn -- Debei, Stefano -- De Cecco, Mariolino -- El-Maarry, Mohamed Ramy -- Ferri, Francesca -- Fornasier, Sonia -- Fulle, Marco -- Gaskell, Robert -- Giacomini, Lorenza -- Groussin, Olivier -- Guilbert-Lepoutre, Aurelie -- Gutierrez-Marques, P -- Gutierrez, Pedro J -- Guttler, Carsten -- Hoekzema, Nick -- Hofner, Sebastian -- Hviid, Stubbe F -- Ip, Wing-Huen -- Jorda, Laurent -- Knollenberg, Jorg -- Kovacs, Gabor -- Kramm, Rainer -- Kuhrt, Ekkehard -- Kuppers, Michael -- La Forgia, Fiorangela -- Lara, Luisa M -- Lazzarin, Monica -- Lee, Vicky -- Leyrat, Cedric -- Lin, Zhong-Yi -- Lopez Moreno, Jose J -- Lowry, Stephen -- Magrin, Sara -- Maquet, Lucie -- Marchi, Simone -- Marzari, Francesco -- Massironi, Matteo -- Michalik, Harald -- Moissl, Richard -- Mottola, Stefano -- Naletto, Giampiero -- Oklay, Nilda -- Pajola, Maurizio -- Preusker, Frank -- Scholten, Frank -- Thomas, Nicolas -- Toth, Imre -- Tubiana, Cecilia -- England -- Nature. 2015 Jul 2;523(7558):63-6. doi: 10.1038/nature14564.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Gottingen, Germany. ; University of Maryland, Department of Astronomy, College Park, Maryland 20742-2421, USA. ; Scientific Support Office, European Space Research and Technology Centre/ESA, Keplerlaan 1, Postbus 299, 2201 AZ Noordwijk ZH, The Netherlands. ; University of Padova, Department of Physics and Astronomy, Vicolo dell'Osservatorio 3, 35122 Padova, Italy. ; Laboratoire d'Astrophysique de Marseille, UMR 7326, CNRS and Aix Marseille Universite, 13388 Marseille Cedex 13, France. ; 1] Centro de Astrobiologia, CSIC-INTA, 28850 Torrejon de Ardoz, Madrid, Spain [2] International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland. ; 1] Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden [2] PAS Space Research Center, Bartycka 18A, 00716 Warszawa, Poland. ; Institut fur Geophysik und extraterrestrische Physik (IGEP), Technische Universitat Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany. ; 1] University of Maryland, Department of Astronomy, College Park, Maryland 20742-2421, USA [2] Akademie der Wissenschaften zu Gottingen and Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg 3, 37077 Gottingen, Germany. ; LESIA-Observatoire de Paris, CNRS, Universite Pierre et Marie Curie, Universite Paris Diderot, 5 place Jules Janssen, 92195 Meudon, France. ; LATMOS, CNRS/UVSQ/IPSL, 11 boulevard d'Alembert, 78280 Guyancourt, France. ; Centro di Ateneo di Studi ed Attivita Spaziali "Giuseppe Colombo" (CISAS), University of Padova, via Venezia 15, 35131 Padova, Italy. ; INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy. ; CNR-IFN UOS Padova LUXOR, via Trasea 7, 35131 Padova, Italy. ; Centro de Astrobiologia, CSIC-INTA, 28850 Torrejon de Ardoz, Madrid, Spain. ; Department of Industrial Engineering, University of Padova, via Venezia 1, 35131 Padova, Italy. ; University of Trento, via Mesiano 77, 38100 Trento, Italy. ; Physikalisches Institut der Universitat Bern, Sidlerstrasse 5, 3012 Bern, Switzerland. ; INAF Osservatorio Astronomico, via Tiepolo 11, 34014 Trieste, Italy. ; Planetary Science Institute, Tucson, Arizona 85719, USA. ; Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, 18008 Granada, Spain. ; Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Institut fur Planetenforschung, Rutherfordstrasse 2, 12489 Berlin, Germany. ; National Central University, Graduate Institute of Astronomy, 300 Chung-Da Rd, Chung-Li 32054, Taiwan. ; Operations Department, European Space Astronomy Centre/ESA, PO Box 78, 28691 Villanueva de la Canada, Madrid, Spain. ; The University of Kent, School of Physical Sciences, Canterbury, Kent CT2 7NZ, UK. ; University of Padova, Deptartment of Physics and Astronomy, via Marzolo 8, 35131 Padova, Italy. ; Solar System Exploration Research Virtual Institute, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, Colorado 80302, USA. ; Dipartimento di Geoscienze, University of Padova, via Giovanni Gradenigo 6, 35131 Padova, Italy. ; Institut fur Datentechnik und Kommunikationsnetze der Technische Universitat Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig, Germany. ; 1] Centro di Ateneo di Studi ed Attivita Spaziali "Giuseppe Colombo" (CISAS), University of Padova, via Venezia 15, 35131 Padova, Italy [2] CNR-IFN UOS Padova LUXOR, via Trasea 7, 35131 Padova, Italy [3] University of Padova, Department of Information Engineering, via Gradenigo 6/B, 35131 Padova, Italy. ; Konkoly Observatory of the Hungarian Academy of Sciences, PO Box 67, 1525 Budapest, Hungary.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26135448" target="_blank"〉PubMed〈/a〉

Description: The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. The peculiar bilobed shape of comet 67P/Churyumov-Gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavation by outgassing at the interface between the two lobes. Here we report that the comet's major lobe is enveloped by a nearly continuous set of strata, up to 650 metres thick, which are independent of an analogous stratified envelope on the minor lobe. Gravity vectors computed for the two lobes separately are closer to perpendicular to the strata than those calculated for the entire nucleus and adjacent to the neck separating the two lobes. Therefore comet 67P/Churyumov-Gerasimenko is an accreted body of two distinct objects with 'onion-like' stratification, which formed before they merged. We conclude that gentle, low-velocity collisions occurred between two fully formed kilometre-sized cometesimals in the early stages of the Solar System. The notable structural similarities between the two lobes of comet 67P/Churyumov-Gerasimenko indicate that the early-forming cometesimals experienced similar primordial stratified accretion, even though they formed independently.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Massironi, Matteo -- Simioni, Emanuele -- Marzari, Francesco -- Cremonese, Gabriele -- Giacomini, Lorenza -- Pajola, Maurizio -- Jorda, Laurent -- Naletto, Giampiero -- Lowry, Stephen -- El-Maarry, Mohamed Ramy -- Preusker, Frank -- Scholten, Frank -- Sierks, Holger -- Barbieri, Cesare -- Lamy, Philippe -- Rodrigo, Rafael -- Koschny, Detlef -- Rickman, Hans -- Keller, Horst Uwe -- A'Hearn, Michael F -- Agarwal, Jessica -- Auger, Anne-Therese -- Barucci, M Antonella -- Bertaux, Jean-Loup -- Bertini, Ivano -- Besse, Sebastien -- Bodewits, Dennis -- Capanna, Claire -- Da Deppo, Vania -- Davidsson, Bjorn -- Debei, Stefano -- De Cecco, Mariolino -- Ferri, Francesca -- Fornasier, Sonia -- Fulle, Marco -- Gaskell, Robert -- Groussin, Olivier -- Gutierrez, Pedro J -- Guttler, Carsten -- Hviid, Stubbe F -- Ip, Wing-Huen -- Knollenberg, Jorg -- Kovacs, Gabor -- Kramm, Rainer -- Kuhrt, Ekkehard -- Kuppers, Michael -- La Forgia, Fiorangela -- Lara, Luisa M -- Lazzarin, Monica -- Lin, Zhong-Yi -- Lopez Moreno, Jose J -- Magrin, Sara -- Michalik, Harald -- Mottola, Stefano -- Oklay, Nilda -- Pommerol, Antoine -- Thomas, Nicolas -- Tubiana, Cecilia -- Vincent, Jean-Baptiste -- England -- Nature. 2015 Oct 15;526(7573):402-5. doi: 10.1038/nature15511. Epub 2015 Sep 28.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Dipartimento di Geoscienze, University of Padova, via G. Gradenigo 6, 35131 Padova, Italy. ; Centro di Ateneo di Studi ed Attivita Spaziali "Giuseppe Colombo" (CISAS), University of Padova, via Venezia 15, 35131 Padova, Italy. ; CNR-IFN UOS Padova LUXOR, via Trasea 7, 35131 Padova, Italy. ; University of Padova, Department of Physics and Astronomy, Vicolo dell'Osservatorio 3, 35122 Padova, Italy. ; INAF, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy. ; Aix Marseille Universite, CNRS, LAM (Laboratoire d'Astrophysique de Marseille), UMR 7326, 38 rue Frederic Joliot-Curie, 13388 Marseille, France. ; Department of Information Engineering, University of Padova, via Gradenigo 6/B, 35131 Padova, Italy. ; The University of Kent, School of Physical Sciences, Canterbury, Kent CT2 7NZ, UK. ; Physikalisches Institut der Universitat Bern, Sidlerstrasse 5, 3012 Bern, Switzerland. ; Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Institut fur Planetenforschung, Rutherfordstrasse 2, 12489 Berlin, Germany. ; Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig Weg 3, 37077 Gottingen, Germany. ; Centro de Astrobiologia, CSIC-INTA, 28850 Torrejon de Ardoz, Madrid, Spain. ; International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland. ; Scientific Support Office, European Space Research and Technology Centre/ESA, Keplerlaan 1, Postbus 299, 2201 AZ Noordwijk ZH, The Netherlands. ; Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden. ; PAS Space Research Center, Bartycka 18A, 00716 Warszawa, Poland. ; Institut fur Geophysik und extraterrestrische Physik (IGEP), Technische Universitat Braunschweig, Mendelssohnstrasse 3, 38106 Braunschweig, Germany. ; University of Maryland, Department of Astronomy, College Park, Maryland 20742-2421, USA. ; Akademie der Wissenschaften zu Gottingen and Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig Weg 3, 37077 Gottingen, Germany. ; LESIA-Observatoire de Paris, CNRS, Universite Pierre et Marie Curie, Universite Paris Diderot, 5 place J. Janssen, 92195 Meudon, France. ; LATMOS, CNRS/UVSQ/IPSL, 11 boulevard d'Alembert, 78280 Guyancourt, France. ; Department of Industrial Engineering, University of Padova, via Venezia 1, 35131 Padova, Italy. ; University of Trento, Via Mesiano 77, 38100 Trento, Italy. ; INAF-Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy. ; Planetary Science Institute, Tucson, Arizona 85719, USA. ; Instituto de Astrofisica de Andalucia (CSIC), Glorieta de la Astronomia s/n, 18008 Granada, Spain. ; National Central University, Graduate Institute of Astronomy, 300 Chung-Da Road, Chung-Li 32054 Taiwan. ; Operations Department, European Space Astronomy Centre/ESA, PO Box 78, 28691 Villanueva de la Canada, Madrid, Spain. ; Institut fur Datentechnik und Kommunikationsnetze der TU Braunschweig, Hans-Sommer Strasse 66, 38106 Braunschweig, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26416730" target="_blank"〉PubMed〈/a〉

Description: The European Space Agency's Rosetta mission encountered the main-belt asteroid (2867) Steins while on its way to rendezvous with comet 67P/Churyumov-Gerasimenko. Images taken with the OSIRIS (optical, spectroscopic, and infrared remote( )imaging system) cameras on board Rosetta show that Steins is an oblate body with an effective spherical diameter of 5.3 kilometers. Its surface does not show color variations. The morphology of Steins is dominated by linear faults and a large 2.1-kilometer-diameter crater near its south pole. Crater counts reveal a distinct lack of small craters. Steins is not solid rock but a rubble pile and has a conical appearance that is probably the result of reshaping due to Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) spin-up. The OSIRIS images constitute direct evidence for the YORP effect on a main-belt asteroid.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Keller, H U -- Barbieri, C -- Koschny, D -- Lamy, P -- Rickman, H -- Rodrigo, R -- Sierks, H -- A'Hearn, M F -- Angrilli, F -- Barucci, M A -- Bertaux, J-L -- Cremonese, G -- Da Deppo, V -- Davidsson, B -- De Cecco, M -- Debei, S -- Fornasier, S -- Fulle, M -- Groussin, O -- Gutierrez, P J -- Hviid, S F -- Ip, W-H -- Jorda, L -- Knollenberg, J -- Kramm, J R -- Kuhrt, E -- Kuppers, M -- Lara, L-M -- Lazzarin, M -- Lopez Moreno, J -- Marzari, F -- Michalik, H -- Naletto, G -- Sabau, L -- Thomas, N -- Wenzel, K-P -- Bertini, I -- Besse, S -- Ferri, F -- Kaasalainen, M -- Lowry, S -- Marchi, S -- Mottola, S -- Sabolo, W -- Schroder, S E -- Spjuth, S -- Vernazza, P -- New York, N.Y. -- Science. 2010 Jan 8;327(5962):190-3. doi: 10.1126/science.1179559.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany. keller@linmpi.mpg.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/20056887" target="_blank"〉PubMed〈/a〉

Description: Images obtained by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) cameras onboard the Rosetta spacecraft reveal that asteroid 21 Lutetia has a complex geology and one of the highest asteroid densities measured so far, 3.4 +/- 0.3 grams per cubic centimeter. The north pole region is covered by a thick layer of regolith, which is seen to flow in major landslides associated with albedo variation. Its geologically complex surface, ancient surface age, and high density suggest that Lutetia is most likely a primordial planetesimal. This contrasts with smaller asteroids visited by previous spacecraft, which are probably shattered bodies, fragments of larger parents, or reaccumulated rubble piles.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sierks, H -- Lamy, P -- Barbieri, C -- Koschny, D -- Rickman, H -- Rodrigo, R -- A'Hearn, M F -- Angrilli, F -- Barucci, M A -- Bertaux, J-L -- Bertini, I -- Besse, S -- Carry, B -- Cremonese, G -- Da Deppo, V -- Davidsson, B -- Debei, S -- De Cecco, M -- De Leon, J -- Ferri, F -- Fornasier, S -- Fulle, M -- Hviid, S F -- Gaskell, R W -- Groussin, O -- Gutierrez, P -- Ip, W -- Jorda, L -- Kaasalainen, M -- Keller, H U -- Knollenberg, J -- Kramm, R -- Kuhrt, E -- Kuppers, M -- Lara, L -- Lazzarin, M -- Leyrat, C -- Lopez Moreno, J J -- Magrin, S -- Marchi, S -- Marzari, F -- Massironi, M -- Michalik, H -- Moissl, R -- Naletto, G -- Preusker, F -- Sabau, L -- Sabolo, W -- Scholten, F -- Snodgrass, C -- Thomas, N -- Tubiana, C -- Vernazza, P -- Vincent, J-B -- Wenzel, K-P -- Andert, T -- Patzold, M -- Weiss, B P -- New York, N.Y. -- Science. 2011 Oct 28;334(6055):487-90. doi: 10.1126/science.1207325.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Max-Planck-Institut fur Sonnensystemforschung, Max-Planck-Strasse 2, 37191 Katlenburg-Lindau, Germany. sierks@mps.mpg.de〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22034428" target="_blank"〉PubMed〈/a〉

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Taylor, M G G T -- Alexander, C -- Altobelli, N -- Fulle, M -- Fulchignoni, M -- Grun, E -- Weissman, P -- New York, N.Y. -- Science. 2015 Jan 23;347(6220):387. doi: 10.1126/science.aaa4542.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉European Space Research and Technology Centre, Science and Robotic Exploration Directorate, European Space Agency, Noordwijk, Netherlands. mtaylor@cosmos.esa.int. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; European Space Astronomy Centre, Science and Robotic Exploration Directorate, European Space Agency, Madrid, Spain. ; INAF-Osservatorio Astronomico, Trieste, Italy. ; Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, France. ; Max-Planck-Institut fur Kernphysik, Heidelberg, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25613884" target="_blank"〉PubMed〈/a〉

Description: Images of comet 67P/Churyumov-Gerasimenko acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) imaging system onboard the European Space Agency's Rosetta spacecraft at scales of better than 0.8 meter per pixel show a wide variety of different structures and textures. The data show the importance of airfall, surface dust transport, mass wasting, and insolation weathering for cometary surface evolution, and they offer some support for subsurface fluidization models and mass loss through the ejection of large chunks of material.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Thomas, Nicolas -- Sierks, Holger -- Barbieri, Cesare -- Lamy, Philippe L -- Rodrigo, Rafael -- Rickman, Hans -- Koschny, Detlef -- Keller, Horst Uwe -- Agarwal, Jessica -- A'Hearn, Michael F -- Angrilli, Francesco -- Auger, Anne-Therese -- Barucci, M Antonella -- Bertaux, Jean-Loup -- Bertini, Ivano -- Besse, Sebastien -- Bodewits, Dennis -- Cremonese, Gabriele -- Da Deppo, Vania -- Davidsson, Bjorn -- De Cecco, Mariolino -- Debei, Stefano -- El-Maarry, Mohamed Ramy -- Ferri, Francesca -- Fornasier, Sonia -- Fulle, Marco -- Giacomini, Lorenza -- Groussin, Olivier -- Gutierrez, Pedro J -- Guttler, Carsten -- Hviid, Stubbe F -- Ip, Wing-Huen -- Jorda, Laurent -- Knollenberg, Jorg -- Kramm, J-Rainer -- Kuhrt, Ekkehard -- Kuppers, Michael -- La Forgia, Fiorangela -- Lara, Luisa M -- Lazzarin, Monica -- Lopez Moreno, Jose J -- Magrin, Sara -- Marchi, Simone -- Marzari, Francesco -- Massironi, Matteo -- Michalik, Harald -- Moissl, Richard -- Mottola, Stefano -- Naletto, Giampiero -- Oklay, Nilda -- Pajola, Maurizio -- Pommerol, Antoine -- Preusker, Frank -- Sabau, Lola -- Scholten, Frank -- Snodgrass, Colin -- Tubiana, Cecilia -- Vincent, Jean-Baptiste -- Wenzel, Klaus-Peter -- New York, N.Y. -- Science. 2015 Jan 23;347(6220):aaa0440. doi: 10.1126/science.aaa0440.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Physikalisches Institut, Sidlerstrasse 5, University of Bern, 3012, Bern, Switzerland. nicolas.thomas@space.unibe.ch. ; Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077, Gottingen, Germany. ; Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy. ; Laboratoire d'Astrophysique de Marseille, UMR 7326, CNRS, and Aix Marseille Universite, 38 Rue Frederic Joliot-Curie, 13388 Marseille Cedex 13, France. ; International Space Science Institute, Hallerstrasse 6, 3012 Bern, Switzerland, and Centro de Astrobiologia, Consejo Superior de Investigaciones Cientificas - Instituto Nacional de Tecnica Aeroespacial, 28850 Torrejon de Ardoz, Madrid, Spain. ; Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden, and Polish Academy of Sciences Space Research Center, Bartycka 18A, PL-00716 Warszawa, Poland. ; Scientific Support Office, European Space Agency, 2201, Noordwijk, Netherlands. ; Institute for Geophysics and Extraterrestrial Physics, Technische Universitat Braunschweig, 38106, Braunschweig, Germany. Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Institut fur Planetenforschung, Asteroiden und Kometen, Rutherfordstrasse 2, 12489 Berlin, Germany. ; Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA. ; Department of Industrial Engineering, University of Padova, via Venezia 1, 35131 Padova, Italy. ; Aix Marseille Universite, CNRS, Laboratoire d'Astrophysique de Marseille, UMR 7326, 38 rue Frederic Joliot-Curie, 13388 Marseille, France. ; Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, CNRS, Universite Paris 06, Universite Paris-Diderot, 5 Place J. Janssen, 92195, Meudon, France. ; Laboratoire Atmospheres, Milieux, Observations Spatiales, CNRS/UVSQ/IPSL, 11 Boulevard d'Alembert, 78280, Guyancourt, France. ; Centro di Ateneo di Studi ed Attivita Spaziali, "Giuseppe Colombo" (CISAS), University of Padova, Via Venezia 15, 35131 Padova, Italy. ; Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy. ; CNR-IFN UOS Padova LUXOR, Via Trasea, 7, 35131 Padova, Italy. ; Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden. ; UNITN, Universita di Trento, Via Mesiano, 77, 38100 Trento, Italy. ; Physikalisches Institut, Sidlerstrasse 5, University of Bern, 3012, Bern, Switzerland. ; INAF, Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy. ; Dipartimento di Geoscienze, University of Padova, via G. Gradenigo 6, 35131 Padova, Italy. ; Instituto de Astrofisica de Andalucia (CSIC), c/ Glorieta de la Astronomia s/n, 18008 Granada, Spain. ; Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Institut fur Planetenforschung, Asteroiden und Kometen, Rutherfordstrasse 2, 12489 Berlin, Germany. Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077, Gottingen, Germany. ; National Central University, Graduate Institute of Astronomy, 300 Chung-Da Road, Chung-Li 32054, Taiwan. ; Laboratoire d'Astrophysique de Marseille, 38 Rue de Frederic Joliot-Curie, 13388 Marseille Cedex 13, France. ; Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Institut fur Planetenforschung, Asteroiden und Kometen, Rutherfordstrasse 2, 12489 Berlin, Germany. ; Science Operations Department, European Space Astronomy Centre/European Space Agency, Post Office Box 78, 28691 Villanueva de la Canada, Madrid, Spain. ; Solar System Exploration Research Virtual Institute, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302, USA. ; Dipartimento di Geoscienze, University of Padova, via G. Gradenigo 6, 35131 Padova, Italy. Centro di Ateneo di Studi ed Attivita Spaziali, "Giuseppe Colombo" (CISAS), University of Padova, Via Venezia 15, 35131 Padova, Italy. ; Institut fur Datentechnik und Kommunikationsnetze der Technische Universitat Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig, Germany. ; University of Padova, Department of Information Engineering, Via Gradenigo 6/B, 35131 Padova, Italy. CNR-IFN UOS Padova LUXOR, Via Trasea, 7, 35131 Padova, Italy. Centro di Ateneo di Studi ed Attivita Spaziali, "Giuseppe Colombo" (CISAS), University of Padova, Via Venezia 15, 35131 Padova, Italy. ; Instituto Nacional de Tecnica Aeroespacial, Carretera de Ajalvir, 28850 Torrejon de Ardoz (Madrid), Spain. ; Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK. Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077, Gottingen, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25613893" target="_blank"〉PubMed〈/a〉

Description: Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency's Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10(-10) to 10(-7) kilograms, and 48 grains of mass 10(-5) to 10(-2) kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 +/- 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Rotundi, Alessandra -- Sierks, Holger -- Della Corte, Vincenzo -- Fulle, Marco -- Gutierrez, Pedro J -- Lara, Luisa -- Barbieri, Cesare -- Lamy, Philippe L -- Rodrigo, Rafael -- Koschny, Detlef -- Rickman, Hans -- Keller, Horst Uwe -- Lopez-Moreno, Jose J -- Accolla, Mario -- Agarwal, Jessica -- A'Hearn, Michael F -- Altobelli, Nicolas -- Angrilli, Francesco -- Barucci, M Antonietta -- Bertaux, Jean-Loup -- Bertini, Ivano -- Bodewits, Dennis -- Bussoletti, Ezio -- Colangeli, Luigi -- Cosi, Massimo -- Cremonese, Gabriele -- Crifo, Jean-Francois -- Da Deppo, Vania -- Davidsson, Bjorn -- Debei, Stefano -- De Cecco, Mariolino -- Esposito, Francesca -- Ferrari, Marco -- Fornasier, Sonia -- Giovane, Frank -- Gustafson, Bo -- Green, Simon F -- Groussin, Olivier -- Grun, Eberhard -- Guttler, Carsten -- Herranz, Miguel L -- Hviid, Stubbe F -- Ip, Wing -- Ivanovski, Stavro -- Jeronimo, Jose M -- Jorda, Laurent -- Knollenberg, Joerg -- Kramm, Rainer -- Kuhrt, Ekkehard -- Kuppers, Michael -- Lazzarin, Monica -- Leese, Mark R -- Lopez-Jimenez, Antonio C -- Lucarelli, Francesca -- Lowry, Stephen C -- Marzari, Francesco -- Epifani, Elena Mazzotta -- McDonnell, J Anthony M -- Mennella, Vito -- Michalik, Harald -- Molina, Antonio -- Morales, Rafael -- Moreno, Fernando -- Mottola, Stefano -- Naletto, Giampiero -- Oklay, Nilda -- Ortiz, Jose L -- Palomba, Ernesto -- Palumbo, Pasquale -- Perrin, Jean-Marie -- Rodriguez, Julio -- Sabau, Lola -- Snodgrass, Colin -- Sordini, Roberto -- Thomas, Nicolas -- Tubiana, Cecilia -- Vincent, Jean-Baptiste -- Weissman, Paul -- Wenzel, Klaus-Peter -- Zakharov, Vladimir -- Zarnecki, John C -- New York, N.Y. -- Science. 2015 Jan 23;347(6220):aaa3905. doi: 10.1126/science.aaa3905.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Via Fosso del Cavaliere, 100, 0133 Rome, Italy. Universita degli Studi di Napoli "Parthenope," Dipartimento di Scienze e Tecnologie, CDN IC4, 80143 Naples, Italy. rotundi@uniparthenope.it. ; Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany. ; Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Via Fosso del Cavaliere, 100, 0133 Rome, Italy. ; Osservatorio Astronomico, INAF, Via Tiepolo 11, 34143 Trieste, Italy. ; Instituto de Astrofisica de Andalucia, Consejo Superior de Investigaciones Cientificas (CSIC), P.O. Box 3008, 18080 Granada, Spain. ; Department of Physics and Astronomy, Padova University, Vicolo dell'Osservatorio 3, 35122 Padova, Italy. ; Laboratoire d'Astrophysique de Marseille, UMR 7326, CNRS and Aix-Marseille Universite, 13388 Marseille, France. ; Centro de Astrobiologia (Instituto Nacional de Tecnica Aerospacial-CSIC), 28691 Villanueva de la Canada, Madrid, Spain. International Space Science Institute, Hallerstrasse 6, CH-3012 Bern, Switzerland. ; Scientific Support Office, European Space Agency, 2201 Noordwijk, Netherlands. ; Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden. Polish Academy of Sciences Space Research Center, Bartycka 18A, PL-00716 Warszawa, Poland. ; Institute for Geophysics and Extraterrestrial Physics, Technische Universitat Braunschweig, Braunschweig 38106, Germany. ; Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Via Fosso del Cavaliere, 100, 0133 Rome, Italy. Universita degli Studi di Napoli "Parthenope," Dipartimento di Scienze e Tecnologie, CDN IC4, 80143 Naples, Italy. ; Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA. ; European Space Agency (ESA)-European Space Astronomy Center (ESAC), Camino Bajo del Castillo, s/n, 28692 Villanueva de la Canada, Madrid, Spagna. ; Department of Mechanical Engineering, University of Padova, via Venezia 1, 35131 Padova, Italy. ; Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, CNRS, Universite Paris 06, Universite Paris-Diderot, 5 place Johannes Janssen, 92195 Meudon, France. ; Laboratoire Atmospheres, Milieux, Observations Spatiales, CNRS/Universite de Versailles Saint-Quentin-en-Yvelines/Institut Pierre-Simon Laplace, 11 boulevard d'Alembert, 78280 Guyancourt, France. ; University of Padova, Centro Interdipartimentale di Studi e Attivita Spaziali (CISAS), via Venezia 15, 35100 Padova, Italy. ; Universita degli Studi di Napoli "Parthenope," Dipartimento di Scienze e Tecnologie, CDN IC4, 80143 Naples, Italy. ; ESA, European Space Research and Technology Centre (ESTEC), Keplerlaan 1, 2201 AZ Noordwijk, Netherlands. ; Selex-ES, Via Albert Einstein, 35, 50013 Campi Bisenzio, Firenze, Italy. ; Osservatorio Astronomico di Padova, INAF, Vicolo dell'Osservatorio 5, 35122 Padova, Italy. ; Consiglio Nazionale delle Ricerche-Istituto di Fotonica e Nanotecnologie-Unita Operativa di Supporto Padova LUXOR, via Trasea 7, 35131 Padova, Italy. ; Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden. ; Universita di Trento, via Mesiano, 77, 38100 Trento, Italy. ; Osservatorio Astronomico di Capodimonte, INAF, Salita Moiariello, 16, 80133 Naples, Italy. ; Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. ; University of Florida, Gainesville, FL 32611, USA. ; Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK. ; Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany. ; Institute of Planetary Research, Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Rutherfordstrasse 2, 12489 Berlin, Germany. ; Institute for Space Science, National Central University, 300 Chung Da Road, 32054 Chung-Li, Taiwan. ; The University of Kent, School of Physical Sciences, Canterbury, Kent CT2 7NZ, UK. ; Department of Physics, University of Padova, 35131 Padova, Italy. ; Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK. The University of Kent, School of Physical Sciences, Canterbury, Kent CT2 7NZ, UK. Unispacekent, Canterbury CT2 8EF, UK. ; Institut fur Datentechnik und Kommunikationsnetze, 38106 Braunschweig, Germany. ; Departamento de Fisica Aplicada, Universidad de Granada, Facultad de Ciencias, Avenida Severo Ochoa, s/n, 18071 Granada, Spain. ; Department of Information Engineering, Padova University, via Gradenigo 6, 35131 Padova, Italy. ; Laboratoire Atmospheres, Milieux, Observations Spatiales, CNRS/Universite de Versailles Saint-Quentin-en-Yvelines/Institut Pierre-Simon Laplace, 11 boulevard d'Alembert, 78280 Guyancourt, France. Observatoire de Haute Provence OSU Pytheas UMS 2244 CNRS-AMU, 04870 Saint Michel l'Observatoire, France. ; Instituto Nacional de Tecnica Aeroespacial, Carretera de Ajalvir, p.k. 4, 28850 Torrejon de Ardoz, Madrid, Spain. ; Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany. Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK. ; Physikalisches Institut, Sidlerstrasse 5, University of Bern, 3012 Bern, Switzerland. ; Planetary Science Section, Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109, USA. ; International Space Science Institute, Hallerstrasse 6, CH-3012 Bern, Switzerland. Planetary and Space Sciences, Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25613898" target="_blank"〉PubMed〈/a〉