ALBERT

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: At least 16 fragments were detected in images of comet C/1999 S4 (LINEAR) taken on 5 August 2000 with the Hubble Space Telescope (HST) and on 6 August with the Very Large Telescope (VLT). Photometric analysis of the fragments indicates that the largest ones have effective spherical diameters of about 100 meters, which implies that the total mass in the observed fragments was about 2 x 10(9) kilograms. The comet's dust tail, which was the most prominent optical feature in August, was produced during a major fragmentation event, whose activity peaked on UT 22.8 +/- 0.2 July 2000. The mass of small particles (diameters less than about 230 micrometers) in the tail was about 4 x 10(8) kilograms, which is comparable to the mass contained in a large fragment and to the total mass lost from water sublimation after 21 July 2000 (about 3 x 10(8) kilograms). HST spectroscopic observations during 5 and 6 July 2000 demonstrate that the nucleus contained little carbon monoxide ice (ratio of carbon monoxide to water is less than or equal to 0.4%), which suggests that this volatile species did not play a role in the fragmentation of C/1999 S4 (LINEAR).〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weaver, H A -- Sekanina, Z -- Toth, I -- Delahodde, C E -- Hainaut, O R -- Lamy, P L -- Bauer, J M -- A'Hearn, M F -- Arpigny, C -- Combi, M R -- Davies, J K -- Feldman, P D -- Festou, M C -- Hook, R -- Jorda, L -- Keesey, M S -- Lisse, C M -- Marsden, B G -- Meech, K J -- Tozzi, G P -- West, R -- New York, N.Y. -- Science. 2001 May 18;292(5520):1329-33.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218-2686, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/11359001" target="_blank"〉PubMed〈/a〉

Description: Analysis of Hubble Space Telescope (HST) images of comet Hale-Bopp (C/1995 O1) suggests that the effective diameter of the nucleus is between 27 to 42 kilometers, which is at least three times larger than that of comet P/Halley. The International Ultraviolet Explorer and HST spectra showed emissions from OH (a tracer of H2O) and CS (a tracer of CS2) starting in April 1996, and from the CO Cameron system (which primarily traces CO2) starting in June 1996. The variation of the H2O production rate with heliocentric distance was consistent with sublimation of an icy body near its subsolar point. The heliocentric variation in the production rates of CS2 and dust was different from that of H2O, which implies that H2O sublimation did not control the CS2 or dust production during these observations.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weaver, H A -- Feldman, P D -- A'Hearn, M F -- Arpigny, C -- Brandt, J C -- Festou, M C -- Haken, M -- McPhate, J B -- Stern, S A -- Tozzi, G P -- New York, N.Y. -- Science. 1997 Mar 28;275(5308):1900-4.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9072959" target="_blank"〉PubMed〈/a〉

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: Understanding how comets work--what drives their activity--is crucial to the use of comets in studying the early solar system. EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation) flew past comet 103P/Hartley 2, one with an unusually small but very active nucleus, taking both images and spectra. Unlike large, relatively inactive nuclei, this nucleus is outgassing primarily because of CO(2), which drags chunks of ice out of the nucleus. It also shows substantial differences in the relative abundance of volatiles from various parts of the nucleus.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉A'Hearn, Michael F -- Belton, Michael J S -- Delamere, W Alan -- Feaga, Lori M -- Hampton, Donald -- Kissel, Jochen -- Klaasen, Kenneth P -- McFadden, Lucy A -- Meech, Karen J -- Melosh, H Jay -- Schultz, Peter H -- Sunshine, Jessica M -- Thomas, Peter C -- Veverka, Joseph -- Wellnitz, Dennis D -- Yeomans, Donald K -- Besse, Sebastien -- Bodewits, Dennis -- Bowling, Timothy J -- Carcich, Brian T -- Collins, Steven M -- Farnham, Tony L -- Groussin, Olivier -- Hermalyn, Brendan -- Kelley, Michael S -- Li, Jian-Yang -- Lindler, Don J -- Lisse, Carey M -- McLaughlin, Stephanie A -- Merlin, Frederic -- Protopapa, Silvia -- Richardson, James E -- Williams, Jade L -- New York, N.Y. -- Science. 2011 Jun 17;332(6036):1396-400. doi: 10.1126/science.1204054.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, University of Maryland, College Park, MD 20742-2421 USA. ma@astro.umd.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21680835" target="_blank"〉PubMed〈/a〉

Description: Deep Impact collided with comet Tempel 1, excavating a crater controlled by gravity. The comet's outer layer is composed of 1- to 100-micrometer fine particles with negligible strength (〈65 pascals). Local gravitational field and average nucleus density (600 kilograms per cubic meter) are estimated from ejecta fallback. Initial ejecta were hot (〉1000 kelvins). A large increase in organic material occurred during and after the event, with smaller changes in carbon dioxide relative to water. On approach, the spacecraft observed frequent natural outbursts, a mean radius of 3.0 +/- 0.1 kilometers, smooth and rough terrain, scarps, and impact craters. A thermal map indicates a surface in equilibrium with sunlight.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉A'Hearn, M F -- Belton, M J S -- Delamere, W A -- Kissel, J -- Klaasen, K P -- McFadden, L A -- Meech, K J -- Melosh, H J -- Schultz, P H -- Sunshine, J M -- Thomas, P C -- Veverka, J -- Yeomans, D K -- Baca, M W -- Busko, I -- Crockett, C J -- Collins, S M -- Desnoyer, M -- Eberhardy, C A -- Ernst, C M -- Farnham, T L -- Feaga, L -- Groussin, O -- Hampton, D -- Ipatov, S I -- Li, J-Y -- Lindler, D -- Lisse, C M -- Mastrodemos, N -- Owen, W M Jr -- Richardson, J E -- Wellnitz, D D -- White, R L -- New York, N.Y. -- Science. 2005 Oct 14;310(5746):258-64. Epub 2005 Sep 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Maryland, College Park, MD 20742, USA. ma@astro.umd.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16150978" target="_blank"〉PubMed〈/a〉

Description: On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meech, K J -- Ageorges, N -- A'Hearn, M F -- Arpigny, C -- Ates, A -- Aycock, J -- Bagnulo, S -- Bailey, J -- Barber, R -- Barrera, L -- Barrena, R -- Bauer, J M -- Belton, M J S -- Bensch, F -- Bhattacharya, B -- Biver, N -- Blake, G -- Bockelee-Morvan, D -- Boehnhardt, H -- Bonev, B P -- Bonev, T -- Buie, M W -- Burton, M G -- Butner, H M -- Cabanac, R -- Campbell, R -- Campins, H -- Capria, M T -- Carroll, T -- Chaffee, F -- Charnley, S B -- Cleis, R -- Coates, A -- Cochran, A -- Colom, P -- Conrad, A -- Coulson, I M -- Crovisier, J -- deBuizer, J -- Dekany, R -- de Leon, J -- Dello Russo, N -- Delsanti, A -- DiSanti, M -- Drummond, J -- Dundon, L -- Etzel, P B -- Farnham, T L -- Feldman, P -- Fernandez, Y R -- Filipovic, M D -- Fisher, S -- Fitzsimmons, A -- Fong, D -- Fugate, R -- Fujiwara, H -- Fujiyoshi, T -- Furusho, R -- Fuse, T -- Gibb, E -- Groussin, O -- Gulkis, S -- Gurwell, M -- Hadamcik, E -- Hainaut, O -- Harker, D -- Harrington, D -- Harwit, M -- Hasegawa, S -- Hergenrother, C W -- Hirst, P -- Hodapp, K -- Honda, M -- Howell, E S -- Hutsemekers, D -- Iono, D -- Ip, W-H -- Jackson, W -- Jehin, E -- Jiang, Z J -- Jones, G H -- Jones, P A -- Kadono, T -- Kamath, U W -- Kaufl, H U -- Kasuga, T -- Kawakita, H -- Kelley, M S -- Kerber, F -- Kidger, M -- Kinoshita, D -- Knight, M -- Lara, L -- Larson, S M -- Lederer, S -- Lee, C-F -- Levasseur-Regourd, A C -- Li, J Y -- Li, Q-S -- Licandro, J -- Lin, Z-Y -- Lisse, C M -- LoCurto, G -- Lovell, A J -- Lowry, S C -- Lyke, J -- Lynch, D -- Ma, J -- Magee-Sauer, K -- Maheswar, G -- Manfroid, J -- Marco, O -- Martin, P -- Melnick, G -- Miller, S -- Miyata, T -- Moriarty-Schieven, G H -- Moskovitz, N -- Mueller, B E A -- Mumma, M J -- Muneer, S -- Neufeld, D A -- Ootsubo, T -- Osip, D -- Pandea, S K -- Pantin, E -- Paterno-Mahler, R -- Patten, B -- Penprase, B E -- Peck, A -- Petitas, G -- Pinilla-Alonso, N -- Pittichova, J -- Pompei, E -- Prabhu, T P -- Qi, C -- Rao, R -- Rauer, H -- Reitsema, H -- Rodgers, S D -- Rodriguez, P -- Ruane, R -- Ruch, G -- Rujopakarn, W -- Sahu, D K -- Sako, S -- Sakon, I -- Samarasinha, N -- Sarkissian, J M -- Saviane, I -- Schirmer, M -- Schultz, P -- Schulz, R -- Seitzer, P -- Sekiguchi, T -- Selman, F -- Serra-Ricart, M -- Sharp, R -- Snell, R L -- Snodgrass, C -- Stallard, T -- Stecklein, G -- Sterken, C -- Stuwe, J A -- Sugita, S -- Sumner, M -- Suntzeff, N -- Swaters, R -- Takakuwa, S -- Takato, N -- Thomas-Osip, J -- Thompson, E -- Tokunaga, A T -- Tozzi, G P -- Tran, H -- Troy, M -- Trujillo, C -- Van Cleve, J -- Vasundhara, R -- Vazquez, R -- Vilas, F -- Villanueva, G -- von Braun, K -- Vora, P -- Wainscoat, R J -- Walsh, K -- Watanabe, J -- Weaver, H A -- Weaver, W -- Weiler, M -- Weissman, P R -- Welsh, W F -- Wilner, D -- Wolk, S -- Womack, M -- Wooden, D -- Woodney, L M -- Woodward, C -- Wu, Z-Y -- Wu, J-H -- Yamashita, T -- Yang, B -- Yang, Y-B -- Yokogawa, S -- Zook, A C -- Zauderer, A -- Zhao, X -- Zhou, X -- Zucconi, J-M -- New York, N.Y. -- Science. 2005 Oct 14;310(5746):265-9. Epub 2005 Sep 8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institute for Astronomy, University of Hawaii at Manoa, 2680 Woodlawn Drive, Honolulu, HI 96822, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16150977" target="_blank"〉PubMed〈/a〉

Description: The impact cratering process on a comet is controversial but holds the key for interpreting observations of the Deep Impact collision with comet 9P/Tempel 1. Mid-infrared data from the Cooled Mid-Infrared Camera and Spectrometer (COMICS) of the Subaru Telescope indicate that the large-scale dust plume ejected by the impact contained a large mass (approximately 10(6) kilograms) of dust and formed two wings approximately +/-45 degrees from the symmetric center, both consistent with gravity as the primary control on the impact and its immediate aftermath. The dust distribution in the inner part of the plume, however, is inconsistent with a pure gravity control and implies that evaporation and expansion of volatiles accelerated dust.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Sugita, S -- Ootsubo, T -- Kadono, T -- Honda, M -- Sako, S -- Miyata, T -- Sakon, I -- Yamashita, T -- Kawakita, H -- Fujiwara, H -- Fujiyoshi, T -- Takato, N -- Fuse, T -- Watanabe, J -- Furusho, R -- Hasegawa, S -- Kasuga, T -- Sekiguchi, T -- Kinoshita, D -- Meech, K J -- Wooden, D H -- Ip, W H -- A'Hearn, M F -- New York, N.Y. -- Science. 2005 Oct 14;310(5746):274-8. Epub 2005 Sep 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Complexity Science and Engineering, University of Tokyo, Kashiwa, Chiba, Japan. sugita@k.u-tokyo.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16166476" target="_blank"〉PubMed〈/a〉

Description: The Hubble Space Telescope made systematic observations of the split comet P/Shoemaker-Levy 9 (SL9) (P designates a periodic comet) starting in July 1993 and continuing through mid-July 1994 when the fragments plunged into Jupiter's atmosphere. Deconvolutions of Wide Field Planetary Camera images indicate that the diameters of some fragments may have been as large as approximately 2 to 4 kilometers, assuming a geometric albedo of 4 percent, but significantly smaller values (that is, 〈 1 kilometer) cannot be ruled out. Most of the fragments (or nuclei) were embedded in circularly symmetric inner comae from July 1993 until late June 1994, implying that there was continuous, but weak, cometary activity. At least a few nuclei fragmented into separate, condensed objects well after the breakup of the SL9 parent body, which argues against the hypothesis that the SL9 fragments were swarms of debris with no dominant, central bodies. Spectroscopic observations taken on 14 July 1994 showed an outburst in magnesium ion emission that was followed closely by a threefold increase in continuum emission, which may have been caused by the electrostatic charging and subsequent explosion of dust as the comet passed from interplanetary space into the jovian magnetosphere. No OH emission was detected, but the derived upper limit on the H2O production rate of approximately 10(27) molecules per second does not necessarily imply that the object was water-poor.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Weaver, H A -- A'Hearn, M F -- Arpigny, C -- Boice, D C -- Feldman, P D -- Larson, S M -- Lamy, P -- Levy, D H -- Marsden, B G -- Meech, K J -- New York, N.Y. -- Science. 1995 Mar 3;267(5202):1282-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Space Telescope Science Institute, Baltimore, MD 21218.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/7871424" target="_blank"〉PubMed〈/a〉