ALBERT

Description: The response of the Martian ionosphere to solar activity is analyzed by taking into account variations in a range of parameters during 4 phases of the solar cycle throughout 2005-2012. Multiple Mars Express datasets have been used (such as Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) in Active Ionospheric Sounding (AIS), MARSIS subsurface and MaRS radio science), which currently cover more than 10 years of solar activity. The topside of the main ionospheric layer behavior is empirically modeled through the neutral scale height parameter, which describes the density distribution in altitude, and can be used as a dynamic monitor of the solar wind-Martian plasma interaction, as well as of the medium's temperature. The main peak, the total electron content, and the relationship between the solar wind dynamic pressure and the maximum thermal pressure of the ionosphere with the solar cycle are assessed. We conclude that the neutral scale height was different in each phase of the solar cycle, having a large variation with solar zenith angle during the moderate ascending and high phases, while there is almost no variation during the moderate descending and low phases. Between end-2007 to end-2009, an almost permanent absence of secondary layer resulted because of the low level of solar X-rays. Also, the ionosphere was more likely to be found in a more continuously magnetized state. The induced magnetic field from the solar wind, even if weak, could be strong enough to penetrate more than at other solar cycle phases.

Description: The ice-rich south polar layered deposits of Mars were probed with the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express orbiter. The radar signals penetrate deep into the deposits (more than 3.7 kilometers). For most of the area, a reflection is detected at a time delay that is consistent with an interface between the deposits and the substrate. The reflected power from this interface indicates minimal attenuation of the signal, suggesting a composition of nearly pure water ice. Maps were generated of the topography of the basal interface and the thickness of the layered deposits. A set of buried depressions is seen within 300 kilometers of the pole. The thickness map shows an asymmetric distribution of the deposits and regions of anomalous thickness. The total volume is estimated to be 1.6 x 10(6) cubic kilometers, which is equivalent to a global water layer approximately 11 meters thick.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Plaut, Jeffrey J -- Picardi, Giovanni -- Safaeinili, Ali -- Ivanov, Anton B -- Milkovich, Sarah M -- Cicchetti, Andrea -- Kofman, Wlodek -- Mouginot, Jeremie -- Farrell, William M -- Phillips, Roger J -- Clifford, Stephen M -- Frigeri, Alessandro -- Orosei, Roberto -- Federico, Costanzo -- Williams, Iwan P -- Gurnett, Donald A -- Nielsen, Erling -- Hagfors, Tor -- Heggy, Essam -- Stofan, Ellen R -- Plettemeier, Dirk -- Watters, Thomas R -- Leuschen, Carlton J -- Edenhofer, Peter -- New York, N.Y. -- Science. 2007 Apr 6;316(5821):92-5. Epub 2007 Mar 15.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17363628" target="_blank"〉PubMed〈/a〉

Description: The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Picardi, Giovanni -- Plaut, Jeffrey J -- Biccari, Daniela -- Bombaci, Ornella -- Calabrese, Diego -- Cartacci, Marco -- Cicchetti, Andrea -- Clifford, Stephen M -- Edenhofer, Peter -- Farrell, William M -- Federico, Costanzo -- Frigeri, Alessandro -- Gurnett, Donald A -- Hagfors, Tor -- Heggy, Essam -- Herique, Alain -- Huff, Richard L -- Ivanov, Anton B -- Johnson, William T K -- Jordan, Rolando L -- Kirchner, Donald L -- Kofman, Wlodek -- Leuschen, Carlton J -- Nielsen, Erling -- Orosei, Roberto -- Pettinelli, Elena -- Phillips, Roger J -- Plettemeier, Dirk -- Safaeinili, Ali -- Seu, Roberto -- Stofan, Ellen R -- Vannaroni, Giuliano -- Watters, Thomas R -- Zampolini, Enrico -- New York, N.Y. -- Science. 2005 Dec 23;310(5756):1925-8. Epub 2005 Nov 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Infocom Department, "La Sapienza" University of Rome, 00184 Rome, Italy.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16319122" target="_blank"〉PubMed〈/a〉

Description: The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 +/- 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kA(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Capaccioni, F -- Coradini, A -- Filacchione, G -- Erard, S -- Arnold, G -- Drossart, P -- De Sanctis, M C -- Bockelee-Morvan, D -- Capria, M T -- Tosi, F -- Leyrat, C -- Schmitt, B -- Quirico, E -- Cerroni, P -- Mennella, V -- Raponi, A -- Ciarniello, M -- McCord, T -- Moroz, L -- Palomba, E -- Ammannito, E -- Barucci, M A -- Bellucci, G -- Benkhoff, J -- Bibring, J P -- Blanco, A -- Blecka, M -- Carlson, R -- Carsenty, U -- Colangeli, L -- Combes, M -- Combi, M -- Crovisier, J -- Encrenaz, T -- Federico, C -- Fink, U -- Fonti, S -- Ip, W H -- Irwin, P -- Jaumann, R -- Kuehrt, E -- Langevin, Y -- Magni, G -- Mottola, S -- Orofino, V -- Palumbo, P -- Piccioni, G -- Schade, U -- Taylor, F -- Tiphene, D -- Tozzi, G P -- Beck, P -- Biver, N -- Bonal, L -- Combe, J-Ph -- Despan, D -- Flamini, E -- Fornasier, S -- Frigeri, A -- Grassi, D -- Gudipati, M -- Longobardo, A -- Markus, K -- Merlin, F -- Orosei, R -- Rinaldi, G -- Stephan, K -- Cartacci, M -- Cicchetti, A -- Giuppi, S -- Hello, Y -- Henry, F -- Jacquinod, S -- Noschese, R -- Peter, G -- Politi, R -- Reess, J M -- Semery, A -- New York, N.Y. -- Science. 2015 Jan 23;347(6220):aaa0628. doi: 10.1126/science.aaa0628.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Rome, Italy. fabrizio.capaccioni@iaps.inaf.it. ; Istituto di Astrofisica e Planetologia Spaziali, Istituto Nazionale di Astrofisica (INAF), Rome, Italy. ; Laboratoire d'Etudes Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris/CNRS/Universite Pierre et Marie Curie[acute accent over last letter in "Universite"]/Universite Paris-Diderot, Meudon, France. ; Institute for Planetary Research, Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Berlin, Germany. ; Universite Grenoble Alpes, CNRS, Institut de Planetologie et d'Astrophysique de Grenoble, Grenoble, France. ; Osservatorio di Capodimonte, INAF, Napoli, Italy. ; Bear Fight Institute, Winthrop, WA 98862, USA. ; University of California, Los Angeles, Los Angeles, CA 90095, USA. ; European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), Noordwijk, Netherlands. ; Institut d'Astrophysique Spatial, CNRS, Orsay, France. ; Dipartimento di Matematica e Fisica "Ennio De Giorgi," Universita del Salento, Italy. ; Space Research Centre, Polish Academy of Sciences, Warsaw, Poland. ; NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USA. ; Space Physics Research Laboratory, The University of Michigan, Ann Arbor, MI 48109, USA. ; Universita di Perugia, Perugia, Italy. ; Lunar Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. ; National Central University, Taipei, Taiwan. ; Departement of Physics, Oxford University, Oxford, UK. ; Institute for Planetary Research, Deutsches Zentrum fur Luft- und Raumfahrt (DLR), Berlin, Germany. Free University of Berlin, Institute of Geosciences, Malteserstrasse 74-100, Building Haus A, 12249 Berlin, Germany. ; Universita "Parthenope," Napoli, Italy. ; Helmholtz-Zentrum Berlin fur Materialien und Energie, Berlin, Germany. ; Osservatorio Astrofisico di Arcetri, INAF, Firenze, Italy. ; Agenzia Spaziale Italiana, Rome, Italy. ; NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USA. Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA. ; Istituto di Radioastronomia, INAF, Bologna, Italy. ; Institut fur Optische Sensorsysteme, DLR, Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25613895" target="_blank"〉PubMed〈/a〉

Description: The Martian bow shock distance has previously been shown to be anti-correlated with solar wind dynamic pressure, but correlated with solar extreme-ultraviolet (EUV) irradiance. Since both of these solar parameters reduce with the square of the distance from the Sun, and Mars' orbit about the Sun increases by ∼0.3 AU from perihelion to aphelion, it is not clear how the bow shock location will respond to variations in these solar parameters, if at all, throughout its orbit. In order to characterise such a response, we use more than 5 Martian years of Mars Express Analyser of Space Plasma and EneRgetic Atoms (ASPERA-3) Electron Spectrometer measurements to automatically identify 11861 bow shock crossings. We have discovered that the bow shock distance as a function of solar longitude has a minimum of 2.39  R M around aphelion, and proceeds to a maximum of 2.65  R M around perihelion, presenting an overall variation of ∼11% throughout the Martian orbit. We have verified previous findings that the bow shock in Southern hemisphere is on average located further away from Mars than in the Northern hemisphere. However, this hemispherical asymmetry is small (total distance variation of ∼2.4%), and the same annual variations occur irrespective of the hemisphere. We have identified that the bow shock location is more sensitive to variations in the solar EUV irradiance than to solar wind dynamic pressure variations. We have proposed possible interaction mechanisms between the solar EUV flux and Martian plasma environment that could explain this annual variation in bow shock location.

Description: Although water vapour is the main species observed in the coma of comet 67P/Churyumov-Gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far. The nucleus of 67P/Churyumov-Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov-Gerasimenko is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet's formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Filacchione, G -- De Sanctis, M C -- Capaccioni, F -- Raponi, A -- Tosi, F -- Ciarniello, M -- Cerroni, P -- Piccioni, G -- Capria, M T -- Palomba, E -- Bellucci, G -- Erard, S -- Bockelee-Morvan, D -- Leyrat, C -- Arnold, G -- Barucci, M A -- Fulchignoni, M -- Schmitt, B -- Quirico, E -- Jaumann, R -- Stephan, K -- Longobardo, A -- Mennella, V -- Migliorini, A -- Ammannito, E -- Benkhoff, J -- Bibring, J P -- Blanco, A -- Blecka, M I -- Carlson, R -- Carsenty, U -- Colangeli, L -- Combes, M -- Combi, M -- Crovisier, J -- Drossart, P -- Encrenaz, T -- Federico, C -- Fink, U -- Fonti, S -- Ip, W H -- Irwin, P -- Kuehrt, E -- Langevin, Y -- Magni, G -- McCord, T -- Moroz, L -- Mottola, S -- Orofino, V -- Schade, U -- Taylor, F -- Tiphene, D -- Tozzi, G P -- Beck, P -- Biver, N -- Bonal, L -- Combe, J-Ph -- Despan, D -- Flamini, E -- Formisano, M -- Fornasier, S -- Frigeri, A -- Grassi, D -- Gudipati, M S -- Kappel, D -- Mancarella, F -- Markus, K -- Merlin, F -- Orosei, R -- Rinaldi, G -- Cartacci, M -- Cicchetti, A -- Giuppi, S -- Hello, Y -- Henry, F -- Jacquinod, S -- Reess, J M -- Noschese, R -- Politi, R -- Peter, G -- England -- Nature. 2016 Jan 21;529(7586):368-72. doi: 10.1038/nature16190. Epub 2016 Jan 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉INAF-IAPS, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy. ; LESIA, Observatoire de Paris/CNRS/UPMC/Universite Paris-Diderot, Meudon, France. ; Institute for Planetary Research, DLR, Berlin, Germany. ; Universite Grenoble Alpes, CNRS, IPAG, Grenoble, France. ; INAF-Osservatorio di Capodimonte, Napoli, Italy. ; UCLA, Los Angeles, California, USA. ; European Space Agency-ESTEC, Noordwijk, The Netherlands. ; Institut d'Astrophysique Spatial CNRS, Orsay, France. ; Dipartimento di Matematica e Fisica "Ennio De Giorgi", Universita del Salento, Lecce, Italy. ; Space Research Centre, Polish Academy of Sciences, Warsaw, Poland. ; NASA JPL, Pasadena, California, USA. ; Space Physics Research Laboratory, The University of Michigan, Michigan, Ann Arbor, USA. ; Universita di Perugia, Perugia, Italy. ; Lunar Planetary Laboratory, University of Arizona, Tucson, Arizona, USA. ; National Central University, Taipei, Taiwan. ; Department of Physics, Oxford University, Oxford, UK. ; Bear Fight Institute, Winthrop, Washington, USA. ; Helmholtz-Zentrum Berlin fur Materialien und Energie, Berlin, Germany. ; INAF-Osservatorio Astrofisico di Arcetri, Firenze, Italy. ; Agenzia Spaziale Italiana, Rome, Italy. ; Istituto di Radioastronomia-INAF, Bologna, Italy. ; Institute of Optical Sensor Systems, DLR, Berlin, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26760209" target="_blank"〉PubMed〈/a〉

Description: This paper is a phenomenological description of the ionospheric plasma and Induced Magnetospheric Boundary (IMB) response to two different types of upstream solar wind events impacting Mars in March 2008, at the solar minimum. A total of 16 Mars Express orbits corresponding to 5 consecutive days are evaluated. STEREO-B at 1 AU, and Mars Express and Mars Odyssey at 1.644 AU detected the arrival of a small transient interplanetary coronal mass ejection (ICME-like) on the 6 and 7 of March respectively. This is the first time that this kind of small solar structure is reported at Mars’ distance. In both cases, it was followed by a large increase in solar wind velocity that lasted for ~10 days. This scenario is simulated with the WSA-ENLIL + Cone solar wind model. At Mars, the ICME-like event caused a strong compression of the magnetosheath and ionosphere, and the recovery lasted for ~3 orbits (~20 h). After that, the fast stream affected the upper ionosphere and the IMB, which radial and tangential motions in regions close to the subsolar point are analyzed. Moreover, a compression in the Martian plasma system is also observed, although weaker than after the ICME-like impact, and several magnetosheath plasma blobs in the upper ionosphere are detected by Mars Express. We conclude that, during solar minimum and at aphelion, small solar wind structures can create larger perturbations than previously expected in the Martian system.

Description: Throughout the first orbit of the NASA Juno mission around Jupiter, the Jupiter InfraRed Auroral Mapper (JIRAM) targeted the northern and southern polar regions several times. The analyses of the acquired images and spectra confirmed a significant presence of methane (CH 4 ) near both poles through its 3.3 μm emission overlapping the H 3 + auroral feature at 3.31 μm. Neither acetylene (C 2 H 2 ) nor ethane (C 2 H 6 ) have been observed so far. The analysis method, developed for the retrieval of H 3 + temperature and abundances and applied to the JIRAM-measured spectra, has enabled an estimate of the effective temperature for methane peak emission and the distribution of its spectral contribution in the polar regions. The enhanced methane inside the auroral oval regions in the two hemispheres at different longitude suggests an excitation mechanism driven by energized particle precipitation from the magnetosphere.

Description: The Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer on board NASA/Juno mission for the study of the Jovian aurorae. The first results of JIRAM's imager channel observations of the H 3 + infrared emission, collected around the first Juno perijove, provide excellent spatial and temporal distribution of the Jovian aurorae, and show the morphology of the main ovals, the polar regions, and the footprints of Io, Europa and Ganymede. The extended Io “tail” persists for ~3 hours after the passage of the satellite flux tube. Multi-arc structures of varied spatial extent appear in both main auroral ovals. Inside the main ovals, intense, localized emissions are observed. In the southern aurora, an evident circular region of strong depletion of H 3 + emissions is partially surrounded by an intense emission arc. The southern aurora is brighter than the north one in these observations. Similar, probably conjugate emission patterns are distinguishable in both polar regions.

Description: The Jupiter InfraRed Auroral Mapper (JIRAM) aboard Juno observed the Jovian South Pole aurora during the first orbit of the mission. H 3 + (trihydrogen cation) and CH 4 (methane) emissions have been identified and measured. The observations have been carried out in nadir and slant viewing both by a L-filtered imager and a 2–5 μm spectrometer. Results from the spectral analysis of the all observations taken over the South Pole by the instrument are reported. The coverage of the southern aurora during these measurements has been partial, but sufficient to determine different regions of temperature and abundance of the H 3 + ion from its emission lines in the 3–4 μm wavelength range. Finally, the results from the southern aurora are also compared with those from the northern ones from the data taken during the same perijove pass and reported by Dinelli et al. (2017).