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Your search keyword '"Debei, Stefano"' showing total 35 results
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35 results on '"Debei, Stefano"'

1. Experimental Evaluation of Pose Initialization Methods for Relative Navigation Between Non-Cooperative Satellites

Author

Chiodini, Sebastiano, Pertile, Marco, Fracchiolla, Pierdomenico, Valmorbida, Andrea, Lorenzini, Enrico, Debei, Stefano, Chiodini, Sebastiano, Pertile, Marco, Fracchiolla, Pierdomenico, Valmorbida, Andrea, Lorenzini, Enrico, and Debei, Stefano

Abstract

In this work, we have analyzed the problem of relative pose initialization between two satellites: a chaser and a non-cooperating target. The analysis has been targeted to two close-range methods based on a monocular camera system: the Sharma-Ventura-D'Amico (SVD) method and the silhouette matching method. Both methods are based on a priori knowledge of the target geometry, but neither fiducial markers nor a priori range measurements or state information are needed. The tests were carried out using a 2U CubeSat mock-up as target attached to a motorized rotary stage to simulate its relative motion with respect to the chaser camera. A motion capture system was used as a reference instrument that provides the fiducial relative motion between the two mock-ups and allows to evaluate the performances of the initialization algorithms analyzed., Comment: To be presented at the 2022 IEEE INTERNATIONAL WORKSHOP ON Metrology for AeroSpace

Published
2022

2. Design of a user-friendly control system for planetary rovers with CPS feature

Author

Chiodini, Sebastiano, Giubilato, Riccardo, Pertile, Marco, Tedesco, Annarita, Accardo, Domenico, Debei, Stefano, Chiodini, Sebastiano, Giubilato, Riccardo, Pertile, Marco, Tedesco, Annarita, Accardo, Domenico, and Debei, Stefano

Abstract

In this paper, we present a user-friendly planetary rover's control system for low latency surface telerobotic. Thanks to the proposed system, an operator can comfortably give commands through the control base station to a rover using commercially available off-the-shelf (COTS) joysticks or by command sequencing with interactive monitoring on the sensed map of the environment. During operations, high situational awareness is made possible thanks to 3D map visualization. The map of the environment is built on the on-board computer by processing the rover's camera images with a visual Simultaneous Localization and Mapping (SLAM) algorithm. It is transmitted via Wi-Fi and displayed on the control base station screen in near real-time. The navigation stack takes as input the visual SLAM data to build a cost map to find the minimum cost path. By interacting with the virtual map, the rover exhibits properties of a Cyber Physical System (CPS) for its self-awareness capabilities. The software architecture is based on the Robot Operative System (ROS) middleware. The system design and the preliminary field test results are shown in the paper., Comment: To be presented at the 8th IEEE International Workshop on Metrology for Aerospace (MetroAeroSpace)

Published
2021

3. Evaluation of 3D CNN Semantic Mapping for Rover Navigation

Author

Chiodini, Sebastiano, Torresin, Luca, Pertile, Marco, Debei, Stefano, Chiodini, Sebastiano, Torresin, Luca, Pertile, Marco, and Debei, Stefano

Abstract

Terrain assessment is a key aspect for autonomous exploration rovers, surrounding environment recognition is required for multiple purposes, such as optimal trajectory planning and autonomous target identification. In this work we present a technique to generate accurate three-dimensional semantic maps for Martian environment. The algorithm uses as input a stereo image acquired by a camera mounted on a rover. Firstly, images are labeled with DeepLabv3+, which is an encoder-decoder Convolutional Neural Networl (CNN). Then, the labels obtained by the semantic segmentation are combined to stereo depth-maps in a Voxel representation. We evaluate our approach on the ESA Katwijk Beach Planetary Rover Dataset., Comment: To be presented at the 7th IEEE International Workshop on Metrology for Aerospace (MetroAerospace)

Published
2020

4. Simulation Framework for Mobile Robots in Planetary-Like Environments

Author

Giubilato, Riccardo, Masili, Andrea, Chiodini, Sebastiano, Pertile, Marco, Debei, Stefano, Giubilato, Riccardo, Masili, Andrea, Chiodini, Sebastiano, Pertile, Marco, and Debei, Stefano

Abstract

In this paper we present a simulation framework for the evaluation of the navigation and localization metrological performances of a robotic platform. The simulator, based on ROS (Robot Operating System) Gazebo, is targeted to a planetary-like research vehicle which allows to test various perception and navigation approaches for specific environment conditions. The possibility of simulating arbitrary sensor setups comprising cameras, LiDARs (Light Detection and Ranging) and IMUs makes Gazebo an excellent resource for rapid prototyping. In this work we evaluate a variety of open-source visual and LiDAR SLAM (Simultaneous Localization and Mapping) algorithms in a simulated Martian environment. Datasets are captured by driving the rover and recording sensors outputs as well as the ground truth for a precise performance evaluation., Comment: To be presented at the 7th IEEE International Workshop on Metrology for Aerospace (MetroAerospace)

Published
2020

5. ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA)

Author

Ferri, Francesca, Karatekin, Ozgur, Lewis, Stephen R., Forget, Francois, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Makinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, Plettemeier, Dirk, Ferri, Francesca, Karatekin, Ozgur, Lewis, Stephen R., Forget, Francois, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Makinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, and Plettemeier, Dirk

Abstract

The entry, descent and landing of Schiaparelli, the ExoMars Entry, descent and landing Demonstrator Module (EDM), offered a rare (once-per-mission) opportunity for in situ investigations of the martian environment over a wide altitude range. The aim of the ExoMars AMELIA experiment was to exploit the Entry, Descent and Landing System (EDLS) engineering measurements for scientific investigations of Mars' atmosphere and surface. Here we present the simulations, modelling and the planned investigations prior to the Entry, Descent and Landing (EDL) event that took place on 19th October 2016. Despite the unfortunate conclusion of the Schiaparelli mission, flight data recorded during the entry and the descent until the loss of signal, have been recovered. These flight data, although limited and affected by transmission interruptions and malfunctions, are essential for investigating the anomaly and validating the EDL operation, but can also contribute towards the partial achievement of AMELIA science objectives.

Published
2019

6. ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA)

Author

Ferri, Francesca, Karatekin, Ozgur, Lewis, Stephen R., Forget, Francois, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Makinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, Plettemeier, Dirk, Ferri, Francesca, Karatekin, Ozgur, Lewis, Stephen R., Forget, Francois, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Makinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, and Plettemeier, Dirk

Abstract

The entry, descent and landing of Schiaparelli, the ExoMars Entry, descent and landing Demonstrator Module (EDM), offered a rare (once-per-mission) opportunity for in situ investigations of the martian environment over a wide altitude range. The aim of the ExoMars AMELIA experiment was to exploit the Entry, Descent and Landing System (EDLS) engineering measurements for scientific investigations of Mars' atmosphere and surface. Here we present the simulations, modelling and the planned investigations prior to the Entry, Descent and Landing (EDL) event that took place on 19th October 2016. Despite the unfortunate conclusion of the Schiaparelli mission, flight data recorded during the entry and the descent until the loss of signal, have been recovered. These flight data, although limited and affected by transmission interruptions and malfunctions, are essential for investigating the anomaly and validating the EDL operation, but can also contribute towards the partial achievement of AMELIA science objectives.

Published
2019

7. Models of Rosetta/OSIRIS 67P dust coma phase function

Author

Moreno, Fernando, Guirado, Daniel, Muñoz, Olga, Bertini, Ivano, Tubiana, Cecilia, Guttler, Carsten, Fulle, Marco, Rotundi, Alessandra, Della Corte, Vincenzo, Ivanovski, Stavro, Rinaldi, Giovanna, Bockelee-Morvan, Dominique, Zakharov, Vladimir, Agarwal, Jessica, Mottola, Stefano, Toth, Imre, Frattin, Elisa, Lara, Luisa, Gutierrez, Pedro, Lin, Zhong Yi, Kolokolova, Ludmilla, Sierks, Holger, Naletto, Giampiero, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Davidsson, Bjorn, Barucci, Maria Antonietta, Bertaux, Jean-Lup, Bodewits, Dennis, Cremonese, Gabriele, Da Deppo, Vania, Debei, Stefano, de Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Ip, Wing, Keller, Uwe, Lazzarin, Monica, Lopez-Moreno, Jose Juan, Marzari, Francesco, Shi, Xian, Moreno, Fernando, Guirado, Daniel, Muñoz, Olga, Bertini, Ivano, Tubiana, Cecilia, Guttler, Carsten, Fulle, Marco, Rotundi, Alessandra, Della Corte, Vincenzo, Ivanovski, Stavro, Rinaldi, Giovanna, Bockelee-Morvan, Dominique, Zakharov, Vladimir, Agarwal, Jessica, Mottola, Stefano, Toth, Imre, Frattin, Elisa, Lara, Luisa, Gutierrez, Pedro, Lin, Zhong Yi, Kolokolova, Ludmilla, Sierks, Holger, Naletto, Giampiero, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Davidsson, Bjorn, Barucci, Maria Antonietta, Bertaux, Jean-Lup, Bodewits, Dennis, Cremonese, Gabriele, Da Deppo, Vania, Debei, Stefano, de Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Ip, Wing, Keller, Uwe, Lazzarin, Monica, Lopez-Moreno, Jose Juan, Marzari, Francesco, and Shi, Xian

Abstract

The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images \citep{Bertini17}. This function show a deep minimum at phase angles near 100$^\circ$, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly-oriented aggregate particles. We show, however, that an ensamble of oriented elongated particles of a wide variety of aspect ratios, with radii $r \gtrsim$10 $\mu$m, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60-70\% range., Comment: Accepted by Astronomical Journal, September 26th, 2018. 21 pages, 5 figures

Published
2018
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8. Models of Rosetta/OSIRIS 67P dust coma phase function

Author

Moreno, Fernando, Guirado, Daniel, Muñoz, Olga, Bertini, Ivano, Tubiana, Cecilia, Guttler, Carsten, Fulle, Marco, Rotundi, Alessandra, Della Corte, Vincenzo, Ivanovski, Stavro, Rinaldi, Giovanna, Bockelee-Morvan, Dominique, Zakharov, Vladimir, Agarwal, Jessica, Mottola, Stefano, Toth, Imre, Frattin, Elisa, Lara, Luisa, Gutierrez, Pedro, Lin, Zhong Yi, Kolokolova, Ludmilla, Sierks, Holger, Naletto, Giampiero, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Davidsson, Bjorn, Barucci, Maria Antonietta, Bertaux, Jean-Lup, Bodewits, Dennis, Cremonese, Gabriele, Da Deppo, Vania, Debei, Stefano, de Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Ip, Wing, Keller, Uwe, Lazzarin, Monica, Lopez-Moreno, Jose Juan, Marzari, Francesco, Shi, Xian, Moreno, Fernando, Guirado, Daniel, Muñoz, Olga, Bertini, Ivano, Tubiana, Cecilia, Guttler, Carsten, Fulle, Marco, Rotundi, Alessandra, Della Corte, Vincenzo, Ivanovski, Stavro, Rinaldi, Giovanna, Bockelee-Morvan, Dominique, Zakharov, Vladimir, Agarwal, Jessica, Mottola, Stefano, Toth, Imre, Frattin, Elisa, Lara, Luisa, Gutierrez, Pedro, Lin, Zhong Yi, Kolokolova, Ludmilla, Sierks, Holger, Naletto, Giampiero, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Davidsson, Bjorn, Barucci, Maria Antonietta, Bertaux, Jean-Lup, Bodewits, Dennis, Cremonese, Gabriele, Da Deppo, Vania, Debei, Stefano, de Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Ip, Wing, Keller, Uwe, Lazzarin, Monica, Lopez-Moreno, Jose Juan, Marzari, Francesco, and Shi, Xian

Abstract

The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images \citep{Bertini17}. This function show a deep minimum at phase angles near 100$^\circ$, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly-oriented aggregate particles. We show, however, that an ensamble of oriented elongated particles of a wide variety of aspect ratios, with radii $r \gtrsim$10 $\mu$m, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60-70\% range., Comment: Accepted by Astronomical Journal, September 26th, 2018. 21 pages, 5 figures

Published
2018
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9. The southern hemisphere of 67P/Churyumov-Gerasimenko : Analysis of the preperihelion size-frequency distribution of boulders >= 7m

Author

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.

Published
2016
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10. Aswan site on comet 67P/Churyumov-Gerasimenko : Morphology, boulder evolution, and spectrophotometry

Author

Pajola, Maurizio, Oklay, Nilda, La Forgia, Fiorangela, Giacomini, Lorenza, Massironi, Matteo, Bertini, Ivano, El-Maarry, M. R., Marzari, Francesco, Preusker, Frank, Scholten, Frank, Hoefner, Sebastian, Lee, Jui-Chi, Vincent, Jean-Baptiste, Groussin, Olivier, Naletto, Giampiero, Lazzarin, Monica, Barbieri, Cesare, 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, Cremonese, Gabriele, Da Deppoll, Vania, Davidsson, Bjoern, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Guettler, Carsten, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kueppers, Michael, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Moreno, Jose J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Thomas, Nicholas, Tubiana, Cecilia, Pajola, Maurizio, Oklay, Nilda, La Forgia, Fiorangela, Giacomini, Lorenza, Massironi, Matteo, Bertini, Ivano, El-Maarry, M. R., Marzari, Francesco, Preusker, Frank, Scholten, Frank, Hoefner, Sebastian, Lee, Jui-Chi, Vincent, Jean-Baptiste, Groussin, Olivier, Naletto, Giampiero, Lazzarin, Monica, Barbieri, Cesare, 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, Cremonese, Gabriele, Da Deppoll, Vania, Davidsson, Bjoern, De Cecco, Mariolino, Debei, Stefano, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Guettler, Carsten, Gutierrez, Pedro J., Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kueppers, Michael, Kuert, Ekkehard, Lara, Luisa M., Lin, Zhong-Yi, Moreno, Jose J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Thomas, Nicholas, and Tubiana, Cecilia

Abstract

Aims. We provide a detailed morphological analysis of the Aswan site on comet 67P/Churyumov-Gerasimenko (67P). We derive the size-frequency distribution of boulders >= 2 m and correlate this distribution with the gravitational slopes for the first time on a comet. We perform the spectral analysis of this region to understand if possible surface variegation is related to the different surface textures observable on the different units. Methods. We used two OSIRIS Narrow Angle Camera (NAC) image data sets acquired on September 19 and 22, 2014, with a scale of 0.5 m/px. Gravitational slopes derived from the 3D shape model of 67P were used to identify and interpret the different units of the site. By means of the high-resolution NAC data sets, boulders >= 2.0 m can be unambiguously identified and extracted using the software ArcGIS. Coregistered and photometrically corrected color cubes were used to perform the spectral analyses, and we retrieved the spectral properties of the Aswan units. Results. The high-resolution morphological map of the Aswan site (0.68 km(2)) shows that this site is characterized by four different units: fine-particle deposits located on layered terrains, gravitational accumulation deposits, taluses, and the outcropping layered terrain. Multiple lineaments are identified on the Aswan cliff, such as fractures, exposed layered outcrops, niches, and terraces. Close to the terrace margin, several arched features observed in plan view suggest that the margin progressively retreats as a result of erosion. The size-frequency of boulders >= 2 m in the entire study area has a power-law index of -3.9 +0.2/-0.3 (1499 boulders >= 2 m/km(2)), suggesting that the Aswan site is mainly dominated by gravitational events triggered by sublimation and/or thermal insolation weathering causing regressive erosion. The boulder size-frequency distribution versus gravitational slopes indicates that when higher gravitational slope terrains are considered, only

Published
2016
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11. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
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12. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
Full Text
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13. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
Full Text
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14. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
Full Text
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15. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
Full Text
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16. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
Full Text
View/download PDF

17. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
Full Text
View/download PDF

18. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
Full Text
View/download PDF

19. Gas outflow and dust transport of comet 67P/Churyumov-Gerasimenko

Author

Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lai, Ian-Lin, Ip, Wing-Huen, Su, Cheng-Chin, Wu, Jong-Shinn, Lee, Jui-Chi, Lin, Zhong-Yi, Liao, Ying, Thomas, Nicolas, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Boudreault, Steven, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guttler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, J. Org, Kovacs, Gabor, Kramm, J. -Rainer, Kuhrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, Marzari, Francesco, Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

Because of the diurnal thermal cycle and the irregular shape of the nucleus, gas outflow of comet 67P/Churyumov-Gerasimenko could be highly anisotropic as indicated by the colliminated dust jet structures on the sunlit side. Based on the OSIRIS imaging observations of the outgassing effect, a simple model of surface sublimation can be constructed by taking into account the dependence on the solar insolation. With preliminary information on the time variability of the global gas production rate, a sequence of gas coma models can be generated at different epochs before and after perihelion. We also investigate different patterns of dust particle dynamics under the influences of nuclear rotation and gas drag. From these considerations, a consistent picture of the spatial distribution of dusty materials across the surface of comet 67P as it moves around the perihelion can be developed. It is found that because of the redeposition of the ejected dust from the Southern hemisphere to the Northern hemisphere during the southern summer season the Hapi region could gain up to 0.4 m while the Wosret region would lose up to 1.8 m of dust mantle per orbit.

Published
2016
Full Text
View/download PDF

20. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author

Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Lee, Jui-Chi, Massironi, Matteo, Ip, Wing-Huen, Giacomini, Lorenza, Ferrari, Sabrina, Penasa, Luca, El-Maarry, Mohamed Ramy, Pajola, Maurizio, Lai, Ian-Lin, Lin, Zhong-Yi, Ferri, Francesca, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Barucci, Maria Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Deller, Jakob, Fornasier, Sonia, Fulle, Marco, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hofmann, Marc, Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kuppers, Michael, Lara, Luisa M., Lazzarin, Monica, Marzari, Francesco, Lopez Moreno, Jose J., Naletto, Giampiero, Oklay, Nilda, Shi, Xian, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.

Published
2016
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21. Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun

Author

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, Björn, Debei, Stefano, De Cecco, Mariolino, Esposito, Francesca, Ferrari, Marco, Fornasier, Sonia, Giovane, Frank, Gustafson, Bo, Green, Simon F., Groussin, Olivier, Gruen, Eberhard, Guettler, Carsten, Herranz, Miguel L., Hviid, Stubbe F., Ip, Wing, Ivanovski, Stavro, Jernimo, Jose M., Jorda, Laurent, Knollenberg, Joerg, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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., 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, Björn, Debei, Stefano, De Cecco, Mariolino, Esposito, Francesca, Ferrari, Marco, Fornasier, Sonia, Giovane, Frank, Gustafson, Bo, Green, Simon F., Groussin, Olivier, Gruen, Eberhard, Guettler, Carsten, Herranz, Miguel L., Hviid, Stubbe F., Ip, Wing, Ivanovski, Stavro, Jernimo, Jose M., Jorda, Laurent, Knollenberg, Joerg, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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, and Zarnecki, John C.

Abstract

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.

Published
2015
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22. On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko

Author

Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutiuerrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, Paetzold, Martin, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutiuerrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, and Paetzold, Martin

Abstract

Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.

Published
2015
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23. The morphological diversity of comet 67P/Churyumov-Gerasimenko

Author

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, Björn, De Cecco, Mariolino, Debei, Stefano, El-Maarry, Mohamed Ramy, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Giacomini, Lorenza, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, 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, 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, Björn, De Cecco, Mariolino, Debei, Stefano, El-Maarry, Mohamed Ramy, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Giacomini, Lorenza, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kramm, J. -Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Moreno, Jose J. Lopez, 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, and Wenzel, Klaus-Peter

Abstract

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.

Published
2015
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24. Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse

Author

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, Bjoern, 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., Guettler, Carsten, Hoekzema, Nick, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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, 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, Bjoern, 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., Guettler, Carsten, Hoekzema, Nick, Hoefner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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, and Tubiana, Cecilia

Abstract

Pits have been observed on many cometary nuclei mapped by spacecraft(1-4). 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(5,6) andmodels(7,8) 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(8,9). Alternative mechanisms like explosive activity(10) 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.

Published
2015
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25. Two independent and primitive envelopes of the bilobate nucleus of comet 67P

Author

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, Björn, Debei, Stefano, De Cecco, Mario Lino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Knollenberg, Joerg, Kovacs, Gabor, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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, 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, Björn, Debei, Stefano, De Cecco, Mario Lino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Groussin, Olivier, Gutierrez, Pedro J., Guettler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Knollenberg, Joerg, Kovacs, Gabor, Kramm, Rainer, Kuehrt, Ekkehard, Kueppers, 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, and Vincent, Jean-Baptiste

Abstract

The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary(1,2) and primordial processes(3,4). 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(5). 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.

Published
2015
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26. Size-frequency distribution of boulders >= 7 m on comet 67P/Churyumov-Gerasimenko

Author

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

Published
2015
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27. On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko

Author

Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutierrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, Paetzold, Martin, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutierrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, and Paetzold, Martin

Abstract

Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.

Published
2015

28. Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse

Author

Vincent, Jean-Baptiste, Bodewits, Dennis, Besse, Sébastien, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Auger, Anne Thérese, Barucci, Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidson, Björn, Debei, Stefano, De Cecco, Mariolino, El-Maarry, Mohamed Ramy, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Giacomini, Olivier, Guilbert-Lepoutre, Aurélie, Gutierrez-Marques, P., Gutiérrez, Pedro J., Güttler, Caster, Hoekzem, Nick, Höfner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Jörg, Kovacs, Gabor, Kramm, Rainer, Kührt, Ekkehard, Küppers, Michael, La Forgia, Fiona, Lara, Luisa M., Lazzarin, Monica, Lee, Vicky, Leyrat, Cédric, Lin, Zhong-Yi, Moreno, Josè J. Lopez, Lowry, S.C., Magrin, Sara, Maquet, Lucie, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Preusjer, Frank, Scholten, Frank, Thomas, Nicolas, Toth, Imre, Tubiana, Cecilia, Vincent, Jean-Baptiste, Bodewits, Dennis, Besse, Sébastien, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe, Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, Keller, Horst Uwe, Agarwal, Jessica, A'Hearn, Michael F., Auger, Anne Thérese, Barucci, Antonella, Bertaux, Jean-Loup, Bertini, Ivano, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidson, Björn, Debei, Stefano, De Cecco, Mariolino, El-Maarry, Mohamed Ramy, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Giacomini, Olivier, Guilbert-Lepoutre, Aurélie, Gutierrez-Marques, P., Gutiérrez, Pedro J., Güttler, Caster, Hoekzem, Nick, Höfner, Sebastian, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Jörg, Kovacs, Gabor, Kramm, Rainer, Kührt, Ekkehard, Küppers, Michael, La Forgia, Fiona, Lara, Luisa M., Lazzarin, Monica, Lee, Vicky, Leyrat, Cédric, Lin, Zhong-Yi, Moreno, Josè J. Lopez, Lowry, S.C., Magrin, Sara, Maquet, Lucie, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Preusjer, Frank, Scholten, Frank, Thomas, Nicolas, Toth, Imre, and Tubiana, Cecilia

Abstract

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 come- tary 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.

Published
2015

29. Two independent and primitive envelopes of the bilobate nucleus of comet 67P

Author

Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Cremonese, Gabriele, Giacomini, Lorenza, Pajola, Maurizio, Jorda, Laurent, Naletto, Giampiero, Lowry, S.C., El-Maarry, Mohammad 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 Thérese, Barucci, M. Antonietta, Bertaux, Jean-Loup, Bertini, Ivano, Besse, Sébastien, Bodewits, Dennis, Capanna, Claire, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Groussin, Olivier, Gutiérrez, Pedro J., Güttler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Knollenberg, Jörg, Kovacs, Gabor, Kramm, Rainer, Kührt, Ekkehard, Küppers, Michael, La Forgia, Fiona, Lara, Luisa M., Lazzarin, Monica, Lin, Zhong-Yi, Moreno, Josè J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Oklay, Nilda, Pommerol, Antoine, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Massironi, Matteo, Simioni, Emanuele, Marzari, Francesco, Cremonese, Gabriele, Giacomini, Lorenza, Pajola, Maurizio, Jorda, Laurent, Naletto, Giampiero, Lowry, S.C., El-Maarry, Mohammad 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 Thérese, Barucci, M. Antonietta, Bertaux, Jean-Loup, Bertini, Ivano, Besse, Sébastien, Bodewits, Dennis, Capanna, Claire, Da Deppo, Vania, Davidsson, Björn, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Groussin, Olivier, Gutiérrez, Pedro J., Güttler, Carsten, Hviid, Stubbe F., Ip, Wing-Huen, Knollenberg, Jörg, Kovacs, Gabor, Kramm, Rainer, Kührt, Ekkehard, Küppers, Michael, La Forgia, Fiona, Lara, Luisa M., Lazzarin, Monica, Lin, Zhong-Yi, Moreno, Josè J. Lopez, Magrin, Sara, Michalik, Harald, Mottola, Stefano, Oklay, Nilda, Pommerol, Antoine, Thomas, Nicolas, Tubiana, Cecilia, and Vincent, Jean-Baptiste

Abstract

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.

Published
2015

30. On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko

Author

Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutierrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, Paetzold, Martin, Sierks, Holger, Barbieri, Cesare, Lamy, Philippe L., Rodrigo, Rafael, Koschny, Detlef, Rickman, Hans, 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, Capanna, Claire, Cremonese, Gabriele, Da Deppo, Vania, Davidsson, Bjoern, Debei, Stefano, De Cecco, Mariolino, Ferri, Francesca, Fornasier, Sonia, Fulle, Marco, Gaskell, Robert, Giacomini, Lorenza, Groussin, Olivier, Gutierrez-Marques, Pablo, Gutierrez, Pedro J., Guettler, Carsten, Hoekzema, Nick, Hviid, Stubbe F., Ip, Wing-Huen, Jorda, Laurent, Knollenberg, Joerg, Kovacs, Gabor, Kramm, J. Rainer, Kuehrt, Ekkehard, Kueppers, Michael, La Forgia, Fiorangela, Lara, Luisa M., Lazzarin, Monica, Leyrat, Cedric, Moreno, Jose J. Lopez, Magrin, Sara, Marchi, Simone, Marzari, Francesco, Massironi, Matteo, Michalik, Harald, Moissl, Richard, Mottola, Stefano, Naletto, Giampiero, Oklay, Nilda, Pajola, Maurizio, Pertile, Marco, Preusker, Frank, Sabau, Lola, Scholten, Frank, Snodgrass, Colin, Thomas, Nicolas, Tubiana, Cecilia, Vincent, Jean-Baptiste, Wenzel, Klaus-Peter, Zaccariotto, Mirco, and Paetzold, Martin

Abstract

Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.

Published
2015

31. E-Type Asteroid (2867) Steins as Imaged by OSIRIS on Board Rosetta

Author

Keller, H.U., Barbieri, Cesare, Koschny, Detlef, Lamy, Philoppe, Rickman, Hans, Rodrigo Montero, Rafael, Sierks, Holger, A’Hearn, Michael F., Angrilli, Francesco, Barucci, M.A., Bertaux, Jean-Loup, Cremonese, G., Deppo, Vania da, Davidsson, B., Cecco, Mariolino de, Debei, Stefano, Fornasier, S., Fulle, Marco, Groussin, Olivier, Gutiérrez, Pedro J., Hviid, Stubbe F., Ip, W., Jorda, Laurent, Knollenberg, Jörg, Kramm, Rainer, Kührt, E., Küppers, Michael, Lara, Luisa María, Lazzarin, Mónica, López-Moreno, José Juan, Marzari, Francesco, Michalik, Harald, Naletto, Giampiero, Sabau-Graziati, Lola, Thomas, Nicolas, Wenzel, Klaus-Peter, Bertini, Ivano, Besse, S., Ferri, Francesca, Kaasalainen, Mikko, Lowry, Stephen C., Marchi, Simone, Mottola, Stefano, Sabolo, Walter, Schröder, Stefan E., Spjuth, S., Vernazza, Pierre, Keller, H.U., Barbieri, Cesare, Koschny, Detlef, Lamy, Philoppe, Rickman, Hans, Rodrigo Montero, Rafael, Sierks, Holger, A’Hearn, Michael F., Angrilli, Francesco, Barucci, M.A., Bertaux, Jean-Loup, Cremonese, G., Deppo, Vania da, Davidsson, B., Cecco, Mariolino de, Debei, Stefano, Fornasier, S., Fulle, Marco, Groussin, Olivier, Gutiérrez, Pedro J., Hviid, Stubbe F., Ip, W., Jorda, Laurent, Knollenberg, Jörg, Kramm, Rainer, Kührt, E., Küppers, Michael, Lara, Luisa María, Lazzarin, Mónica, López-Moreno, José Juan, Marzari, Francesco, Michalik, Harald, Naletto, Giampiero, Sabau-Graziati, Lola, Thomas, Nicolas, Wenzel, Klaus-Peter, Bertini, Ivano, Besse, S., Ferri, Francesca, Kaasalainen, Mikko, Lowry, Stephen C., Marchi, Simone, Mottola, Stefano, Sabolo, Walter, Schröder, Stefan E., Spjuth, S., and Vernazza, Pierre

Abstract

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.

Published
2010

32. Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Author

Keller, Horst Uwe, Küppers, Michael, Fornasier, Sonia, Gutiérrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Jörg, Lowry, Stephen C., Rengel, Miriam, Bertini, Ivano, Cremonese, G.=abriele, Ip, Wing-H., Koschny, Detlef, Kramm, Rainer, Kührt, Ekkehard, Lara, Luisa-Maria, Sierks, Holger, Thomas, Nicolas, Barbieri, Cesare, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, A'Hearn, Michael F., Angrilli, Francesco, Barucci, Maria-Antonella, Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn J.R., De Cecco, Mariolino, Debei, Stefano, Fulle, Marco, Gliem, Fritz, Groussin, Olivier, Lopez Moreno, José J., Marzari, Francesco, Naletto, Giampiero, Sabau, Lola, Sanz Andrés, Angel, Wenzel, Klaus-Peter, Keller, Horst Uwe, Küppers, Michael, Fornasier, Sonia, Gutiérrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Jörg, Lowry, Stephen C., Rengel, Miriam, Bertini, Ivano, Cremonese, G.=abriele, Ip, Wing-H., Koschny, Detlef, Kramm, Rainer, Kührt, Ekkehard, Lara, Luisa-Maria, Sierks, Holger, Thomas, Nicolas, Barbieri, Cesare, Lamy, Philippe, Rickman, Hans, Rodrigo, Rafael, A'Hearn, Michael F., Angrilli, Francesco, Barucci, Maria-Antonella, Bertaux, Jean-Loup, Da Deppo, Vania, Davidsson, Björn J.R., De Cecco, Mariolino, Debei, Stefano, Fulle, Marco, Gliem, Fritz, Groussin, Olivier, Lopez Moreno, José J., Marzari, Francesco, Naletto, Giampiero, Sabau, Lola, Sanz Andrés, Angel, and Wenzel, Klaus-Peter

Abstract

The OSIRIS cameras on the Rosetta spacecraft observed Comet 9P/Tempel 1 from 5 days before to 10 days after it was hit by the Deep Impact projectile. The Narrow Angle Camera (NAC) monitored the cometary dust in 5 different filters. The Wide Angle Camera (WAC) observed through filters sensitive to emissions from OH, CN, Na, and OI together with the associated continuum. Before and after the impact the comet showed regular variations in intensity. The period of the brightness changes is consistent with the rotation period of Tempel 1. The overall brightness of Tempel 1 decreased by about 10% during the OSIRIS observations. The analysis of the impact ejecta shows that no new permanent coma structures were created by the impact. Most of the material moved with ~200 m s-1. Much of it left the comet in the form of icy grains which sublimated and fragmented within the first hour after the impact. The light curve of the comet after the impact and the amount of material leaving the comet (4.5 - 9 x 10^6 kg of water ice and a presumably larger amount of dust) suggest that the impact ejecta were quickly accelerated by collisions with gas molecules. Therefore, the motion of the bulk of the ejecta cannot be described by ballistic trajectories, and the validity of determinations of the density and tensile strength of the nucleus of Tempel 1 with models using ballistic ejection of particles is uncertain. © 2006 Elsevier Inc. All rights reserved.

Published
2007

33. Observations of Comet 9P/Tempel 1 around the Deep Impact event by the OSIRIS cameras onboard Rosetta

Author

Keller, H.U., Küppers, Michael, Fornasier, S., Gutiérrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Jörg, Lowry, Stephen C., Rengel, Miriam, Bertini, Ivano, Cremonese, G., Wing, Ip, Koschny, Detlef, Kramm, Rainer, Kührt, E., Lara, Luisa María, Sierks, Holger, Thomas, Nicolas, Barbieri, Cesare, Lamy, Philoppe, Rickman, Hans, Rodrigo Montero, Rafael, A’Hearn, Michael F., Angrilli, Francesco, Barucci, M.A., Bertaux, Jean-Loup, Deppo, Vania da, Davidsson, B., Cecco, Mariolino de, Debei, Stefano, Fulle, Marco, Gliem, Fritz, Groussin, Olivier, López-Moreno, José Juan, Marzari, Francesco, Naletto, Giampiero, Sabau-Graziati, Lola, Sanz Andrés, Ángel, Wenzel, Klaus-Peter, Keller, H.U., Küppers, Michael, Fornasier, S., Gutiérrez, Pedro J., Hviid, Stubbe F., Jorda, Laurent, Knollenberg, Jörg, Lowry, Stephen C., Rengel, Miriam, Bertini, Ivano, Cremonese, G., Wing, Ip, Koschny, Detlef, Kramm, Rainer, Kührt, E., Lara, Luisa María, Sierks, Holger, Thomas, Nicolas, Barbieri, Cesare, Lamy, Philoppe, Rickman, Hans, Rodrigo Montero, Rafael, A’Hearn, Michael F., Angrilli, Francesco, Barucci, M.A., Bertaux, Jean-Loup, Deppo, Vania da, Davidsson, B., Cecco, Mariolino de, Debei, Stefano, Fulle, Marco, Gliem, Fritz, Groussin, Olivier, López-Moreno, José Juan, Marzari, Francesco, Naletto, Giampiero, Sabau-Graziati, Lola, Sanz Andrés, Ángel, and Wenzel, Klaus-Peter

Abstract

The OSIRIS cameras on the Rosetta spacecraft observed Comet 9P/Tempel 1 from 5 days before to 10 days after it was hit by the Deep Impact projectile. The Narrow Angle Camera (NAC) monitored the cometary dust in 5 different filters. The Wide Angle Camera (WAC) observed through filters sensitive to emissions from OH, CN, Na, and OI together with the associated continuum. Before and after the impact the comet showed regular variations in intensity. The period of the brightness changes is consistent with the rotation period of Tempel 1. The overall brightness of Tempel 1 decreased by about 10% during the OSIRIS observations. The analysis of the impact ejecta shows that no new permanent coma structures were created by the impact. Most of the material moved with ~ 200 m/s. Much of it left the comet in the form of icy grains which sublimated and fragmented within the first hour after the impact. The light curve of the comet after the impact and the amount of material leaving the comet (4.5 - 9 x 10e6 of water ice and a presumably larger amount of dust) suggest that the impact ejecta were quickly accelerated by collisions with gas molecules. Therefore, the motion of the bulk of the ejecta cannot be described by ballistic trajectories, and the validity of determinations of the density and tensile strength of the nucleus of Tempel 1 with models using ballistic ejection of particles is uncertain.

Published
2007

34. ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA)

Author

Ferri, Francesca, Karatekin, Özgür, Lewis, Stephen R., Forget, François, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Mäkinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, Plettemeier, Dirk, Ferri, Francesca, Karatekin, Özgür, Lewis, Stephen R., Forget, François, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Mäkinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, and Plettemeier, Dirk

Abstract

The entry, descent and landing of Schiaparelli, the ExoMars Entry, descent and landing Demonstrator Module (EDM), offered a rare (once-per-mission) opportunity for in situ investigations of the martian environment over a wide altitude range. The aim of the ExoMars AMELIA experiment was to exploit the Entry, Descent and Landing System (EDLS) engineering measurements for scientific investigations of Mars’ atmosphere and surface. Here we present the simulations, modelling and the planned investigations prior to the Entry, Descent and Landing (EDL) event that took place on 19th October 2016. Despite the unfortunate conclusion of the Schiaparelli mission, flight data recorded during the entry and the descent until the loss of signal, have been recovered. These flight data, although limited and affected by transmission interruptions and malfunctions, are essential for investigating the anomaly and validating the EDL operation, but can also contribute towards the partial achievement of AMELIA science objectives.

35. ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA)

Author

Ferri, Francesca, Karatekin, Özgür, Lewis, Stephen R., Forget, François, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Mäkinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, Plettemeier, Dirk, Ferri, Francesca, Karatekin, Özgür, Lewis, Stephen R., Forget, François, Aboudan, Alessio, Colombatti, Giacomo, Bettanini, Carlo, Debei, Stefano, Van Hove, Bart, Dehant, Veronique, Harri, Ari-Matti, Leese, Mark, Mäkinen, Teemu, Millour, Ehouarn, Muller-Wodarg, Ingo, Ori, Gian Gabriele, Pacifici, Andrea, Paris, Sebastien, Patel, Manish, Schoenenberger, Mark, Herath, Jeffrey, Siili, Tero, Spiga, Aymeric, Tokano, Tetsuya, Towner, Martin, Withers, Paul, Asmar, Sami, and Plettemeier, Dirk

Abstract

The entry, descent and landing of Schiaparelli, the ExoMars Entry, descent and landing Demonstrator Module (EDM), offered a rare (once-per-mission) opportunity for in situ investigations of the martian environment over a wide altitude range. The aim of the ExoMars AMELIA experiment was to exploit the Entry, Descent and Landing System (EDLS) engineering measurements for scientific investigations of Mars’ atmosphere and surface. Here we present the simulations, modelling and the planned investigations prior to the Entry, Descent and Landing (EDL) event that took place on 19th October 2016. Despite the unfortunate conclusion of the Schiaparelli mission, flight data recorded during the entry and the descent until the loss of signal, have been recovered. These flight data, although limited and affected by transmission interruptions and malfunctions, are essential for investigating the anomaly and validating the EDL operation, but can also contribute towards the partial achievement of AMELIA science objectives.

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