6 results on '"El-Maarry, Mohamed R."'
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2. Honeycomb Terrain (Mars, Hellas)
- Author
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El Maarry, Mohamed R., primary
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- 2014
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3. The southern hemisphere of 67P/Churyumov-Gerasimenko : Analysis of the preperihelion size-frequency distribution of boulders >= 7m
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Pajola, Maurizio, Lucchetti, Alice, Vincent, Jean-Baptiste, Oklay, Nilda, El-Maarry, Mohamed R., Bertini, Ivano, Naletto, Giampiero, Lazzarin, Monica, Massironi, Matteo, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Boudreault, Steve, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjorn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Gicquel, Adeline, Groussin, Olivier, Gutierrez, Pedro J., Guetler, Carsten, Hofmann, Marc, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lee, Jui-Chi, Lin, Zhong-Yi, Lopez Moreno, Jose J., Marzari, Francesco, Michalik, Harald, Mottola, Stefano, Preusker, Frank, Scholten, Frank, Thomas, Nicholas, Toth, Imre, Tubiana, Cecilia, Pajola, Maurizio, Lucchetti, Alice, Vincent, Jean-Baptiste, Oklay, Nilda, El-Maarry, Mohamed R., Bertini, Ivano, Naletto, Giampiero, Lazzarin, Monica, Massironi, Matteo, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Boudreault, Steve, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjorn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Gicquel, Adeline, Groussin, Olivier, Gutierrez, Pedro J., Guetler, Carsten, Hofmann, Marc, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lee, Jui-Chi, Lin, Zhong-Yi, Lopez Moreno, Jose J., Marzari, Francesco, Michalik, Harald, Mottola, Stefano, Preusker, Frank, Scholten, Frank, Thomas, Nicholas, Toth, Imre, and Tubiana, Cecilia
- Abstract
Aims. We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 2 May 2015 at a distance of 125 km from the nucleus. The scale of this dataset is 2.3 m/px; the high resolution of the images, coupled with the favorable observation phase angle of 62 degrees, provided the possibility to unambiguously identify boulders >= 7 m on the surface of 67P and to manually extract them with the software ArcGIS. We derived the size-frequency distribution of the illuminated southern hemisphere. Results. We found a power-law index of -3.6 +/- 0.2 for the boulders on the southern hemisphere with a diameter range of 7-35 m. The power-law index is equal to the one previously found on northern and equatorial regions of 67P, suggesting that similar boulder formation processes occur in both hemispheres. The power-law index is related to gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. In addition, the presence of a larger number of boulders per km(2) in the southern hemisphere, which is a factor of 3 higher with respect to the northern hemisphere, suggests that the southernmost terrains of 67P are affected by a stronger thermal fracturing and sublimating activity, hence possibly causing larger regressive erosion and gravitational events.
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- 2016
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4. The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m
- Author
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Pajola, Maurizio, primary, Lucchetti, Alice, additional, Vincent, Jean-Baptiste, additional, Oklay, Nilda, additional, El-Maarry, Mohamed R., additional, Bertini, Ivano, additional, Naletto, Giampiero, additional, Lazzarin, Monica, additional, Massironi, Matteo, additional, Sierks, Holger, additional, Barbieri, Cesare, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst U., additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria A., additional, Bertaux, Jean-Loup, additional, Boudreault, Steve, additional, Cremonese, Gabriele, additional, Deppo, Vania Da, additional, Davidsson, Björn, additional, Debei, Stefano, additional, De Cecco, Mariolino, additional, Deller, Jakob, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Gicquel, Adeline, additional, Groussin, Olivier, additional, Gutierrez, Pedro J., additional, Güttler, Carsten, additional, Hofmann, Marc, additional, Höfner, Sebastian, additional, Hviid, Stubbe F., additional, Ip, Wing-Huen, additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kramm, J.-Rainer, additional, Kührt, Ekkehard, additional, Küppers, Michael, additional, La Forgia, Fiorangela, additional, Lara, Luisa M., additional, Lee, Jui-Chi, additional, Lin, Zhong-Yi, additional, Lopez Moreno, Jose J., additional, Marzari, Francesco, additional, Michalik, Harald, additional, Mottola, Stefano, additional, Preusker, Frank, additional, Scholten, Frank, additional, Thomas, Nicholas, additional, Toth, Imre, additional, and Tubiana, Cecilia, additional
- Published
- 2016
- Full Text
- View/download PDF
5. Size-frequency distribution of boulders >= 7 m on comet 67P/Churyumov-Gerasimenko
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Pajola, Maurizio, Vincent, Jean-Baptiste, Guettler, Carsten, Lee, Jui-Chi, Bertini, Ivano, Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Giacomini, Lorenza, Lucchetti, Alice, Barbieri, Cesare, Cremonese, Gabriele, Naletto, Giampiero, Pommerol, Antoine, El-Maarry, Mohamed R., Besse, Sebastien, Kueppers, Michael, La Forgia, Fiorangela, Lazzarin, Monica, Thomas, Nicholas, Auger, Anne-Therese, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Lopez Moreno, Jose J., Magrin, Sara, Marchi, Simone, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Oklay, Nilda, Preusker, Frank, Scholten, Frank, Tubiana, Cecilia, Pajola, Maurizio, Vincent, Jean-Baptiste, Guettler, Carsten, Lee, Jui-Chi, Bertini, Ivano, Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Giacomini, Lorenza, Lucchetti, Alice, Barbieri, Cesare, Cremonese, Gabriele, Naletto, Giampiero, Pommerol, Antoine, El-Maarry, Mohamed R., Besse, Sebastien, Kueppers, Michael, La Forgia, Fiorangela, Lazzarin, Monica, Thomas, Nicholas, Auger, Anne-Therese, Sierks, Holger, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst U., Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria A., Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Lopez Moreno, Jose J., Magrin, Sara, Marchi, Simone, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Oklay, Nilda, Preusker, Frank, Scholten, Frank, and Tubiana, Cecilia
- Abstract
Aims. We derive for the first time the size-frequency distribution of boulders on a comet, 67P/Churyumov-Gerasimenko (67P), computed from the images taken by the Rosetta/OSIRIS imaging system. We highlight the possible physical processes that lead to these boulder size distributions. Methods. We used images acquired by the OSIRIS Narrow Angle Camera, NAC. on 5 and 6 August 2014. The scale of these images (2.44-2.03 m/px) is such that boulders >= 7 m can be identified and manually extracted from the datasets with the software ArcGIS. We derived both global and localized size-frequency distributions. The three-pixel sampling detection, coupled with the favorable shadowine of the surface (observation phase angle ranging from 48 to 53), enables unequivocally detecting boulders scattered all over the illuminated side of 67P. Results. We identify 3546 boulders larger than 7 m on the imaged surface (36.4 km(2)), with a global number density of nearly 100/km(2) and a cumulative size-frequency distribution represented by a power-law with index of -3.6 +0.2/-0.3. The two lobes of 67P appear to have slightly different distributions, with an index of -3.5 +0.2/-0.3 for the main lobe (body) and -4.0 +0.31-0.2 for the small lobe (head). The steeper distribution of the small lobe might be due to a more pervasive fracturing. The difference of the distribution for the connecting region (neck) is much more significant, with an index value of -2.2 +0.2/-0.2. We propose that the boulder field located in the neck area is the result of blocks falling from the contiguous Hathor cliff. The lower slope of the size-frequency distribution we see today in the neck area might be due to the concurrent processes acting on the smallest boulders, such as i) disintegration or fragmentation and vanishing through sublimation; ii) uplifting by gas drag and consequent redistribution; and iii) burial beneath a debris blanket. We also derived the cumulative size-frequency distribution per km(2) of loca
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- 2015
- Full Text
- View/download PDF
6. Size-frequency distribution of boulders ≥7 m on comet 67P/Churyumov-Gerasimenko
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Pajola, Maurizio, primary, Vincent, Jean-Baptiste, additional, Güttler, Carsten, additional, Lee, Jui-Chi, additional, Bertini, Ivano, additional, Massironi, Matteo, additional, Simioni, Emanuele, additional, Marzari, Francesco, additional, Giacomini, Lorenza, additional, Lucchetti, Alice, additional, Barbieri, Cesare, additional, Cremonese, Gabriele, additional, Naletto, Giampiero, additional, Pommerol, Antoine, additional, El-Maarry, Mohamed R., additional, Besse, Sébastien, additional, Küppers, Michael, additional, La Forgia, Fiorangela, additional, Lazzarin, Monica, additional, Thomas, Nicholas, additional, Auger, Anne-Thérèse, additional, Sierks, Holger, additional, Lamy, Philippe, additional, Rodrigo, Rafael, additional, Koschny, Detlef, additional, Rickman, Hans, additional, Keller, Horst U., additional, Agarwal, Jessica, additional, A’Hearn, Michael F., additional, Barucci, Maria A., additional, Bertaux, Jean-Loup, additional, Deppo, Vania Da, additional, Davidsson, Björn, additional, De Cecco, Mariolino, additional, Debei, Stefano, additional, Ferri, Francesca, additional, Fornasier, Sonia, additional, Fulle, Marco, additional, Groussin, Olivier, additional, Gutierrez, Pedro J., additional, Hviid, Stubbe F., additional, Ip, Wing-Huen, additional, Jorda, Laurent, additional, Knollenberg, Jörg, additional, Kramm, J.-Rainer, additional, Kürt, Ekkehard, additional, Lara, Luisa M., additional, Lin, Zhong-Yi, additional, Moreno, Jose J. Lopez, additional, Magrin, Sara, additional, Marchi, Simone, additional, Michalik, Harald, additional, Moissl, Richard, additional, Mottola, Stefano, additional, Oklay, Nilda, additional, Preusker, Frank, additional, Scholten, Frank, additional, and Tubiana, Cecilia, additional
- Published
- 2015
- Full Text
- View/download PDF
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