Contrat Quadriennal Part I : Bilan Scientifique. Part I : Scientific Report

Transcription

1 UMR5109 Contrat Quadriennal Part I : Bilan Scientifique Part I : Scientific Report

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3 1 General Presentation of the Laboratory The Laboratoire de Planétologie de Grenoble (LPG, UMR 5109) is presented as one team for the AERES evaluation, due to its size. The laboratory was created ten years ago with two small teams coming from the Laboratoire des Images et des Signaux (W. Kofman et al.) and from the Laboratoire de Glaciologie et de Géophysique de l Environnement LGGE (B. Schmitt et al.), with a total of 5 researchers and 4 engineers and technicians. Since then, the total permanent staff has increased from 9 up to 18 persons in June During the last two years, the interdisciplinary aspect of the research conducted in our laboratory has significantly increased with the arrival in January 2007 of two CNRS physical chemists from the University Paris Sud and the recruitment in September 2007 of a geologist geophysicist by the Grenoble University ( enseignant chercheur MdC ). The chemistry team was reinforced in October 2008 with another physical chemist who joined the laboratory on a CNRS position from the Chemistry Department (section 13). The integration of these new researchers was one of the main objectives of the previous quadrennial contract. It is a success and has a strong influence on the research orientations of the laboratory, which cover the field of planetary sciences from the planets upper atmosphere, including the Earth, the planetary surfaces and sub surfaces, and the small bodies of the solar system. Our approach includes observations, space data processing and analysis, modelling, original laboratory experiments in support of space exploration and development of space instrumentation in collaboration with space laboratories. The research of our laboratory can be illustrated with some highlights which are selected among recent work published in Nature, Science or Geophysical Research Letters: (i) results concerning the ice cap of Mars (depth of the CO 2 ice, purity of the H 2 O ice); (ii) the possible presence of liquid water in the sub surface of Mars; (iii) the first observation of polarized aurorae; (iv) the negative ion chemistry in the Titan upper atmosphere. The laboratory plays a role of leader for the Consert radar instrument (Principal Investigator, PI) on board the Rosetta mission, launched in 2004 to encounter the comet Churyumov Gerasimenko in A new lecturer ( enseignant chercheur MdC) was hired to reinforce this team and has integrated our laboratory in September Several researchers of our laboratory are Co Investigators (Co I s) for several instruments of major space missions, as for Marsis radar on Mars Express, as well as for optical instruments such as Omega on Mars Express, VIRTIS on Rosetta and DISR on Cassini Huygens. Our laboratory has also always been strongly involved in the analysis and in the valorisation of data coming from the Earth ionospheric incoherent diffusion radars EISCAT, based in Scandinavia. In 2007, an astronomer was hired in LPG to take in charge the observation service of the French community with the EISCAT radars. Our laboratory is organized around three main scientific themes (internally called teams during the quadrennial) and two thematic groups. The three teams are: «Hautes atmosphères planétaires» (Upper Planetary Atmospheres), Matière Moléculaire solide du système solaire (Solid Molecular matter of the Solar System) and «Surfaces and sub surfaces». In order to establish interdisciplinary approaches between the different teams, two thematic groups on Mars and Titan were simultaneously organized to study the cycles of water and organic molecules, on these objects respectively. Our laboratory is involved in strong scientific collaborations with many outstanding laboratories of Planetary Sciences and of other disciplines. In the Observatoire des Sciences de l Univers de Grenoble (OSUG), our main and natural partner is the Laboratoire d Astrophysique de Grenoble (LAOG) with whom we present a project to merge into a single laboratory, but we also have close collaborations with the LGCA and the LGGE. Let us also cite the laboratory of Earth

4 2 Sciences at the Ecole Normale Supérieure of Lyon in the Rhône Alpes Region, at the national level (LATMOS, LCP2E, MNHN, LESIA, IAS ), in Europe (Norway, UK, Germany, Italy, Poland ), in the USA (Univ. Arizona, JPL ) and in Japan. We have also established a collaboration for radar data analysis with Mali, in the frame of the UJF international programme. The excellent scientific activity of our laboratory is shown by the high number of published articles in highly ranked journals of Planetary Sciences (160) with a mean value of 2.8 papers/researcher/year, increasing with years (see table1) with for example 5 papers in Nature, 5 in Science, 1 in Phys. Rev. Lett., 19 in Annales Geophysicae, 18 in Journal of Geophysical Research, 16 in Icarus. The interdisciplinary character of our research naturally induces some scatter over many specialized journals. Our visibility is high, as demonstrated by the number of invited papers in international conferences (38) and the important responsibilities in Planetary Sciences taken by several scientists of our laboratory (see Annex 2). W. Kofman is a member of the Space Science Advisory Committee of ESA, O. Dutuit is the chair of the Exo/Astrobiology scientific group of CNES, Jean Lilensten is the French representative for Space Weather in the COST network, R.Thissen is the only European associated scientist of the INMS instrument on Cassini, several scientists are task leaders in the Europlanet RI FP7 network, W. Kofman is editor of Annales Geophysicae, etc. It is also remarkable for a laboratory of a rather small size, that we obtained two ANR contracts with the leadership and one in collaboration with the LAOG Chercheurs Ens.Cher.+AstronA Chercheurs+EC+AA NB Publis Ratio Pub/Cher. 2,88 1,88 2,60 2,46 3,62 Moy :2,83 Table 1 : researchers and their scientific production Researchers of our laboratory use several large scale instruments, such as EISCAT (Northern radars), Observatories (TBL Pic du Midi, UKIRT in Hawai), synchrotron facilities (ESRF, SOLEIL, ELETTRA) and, last but not least, space instruments on different space missions (Mars Express, Rosetta, Cassini Huygens, MRO ). In the laboratory, two instruments are open to external users, an IR imaging microscope (an OSUG facility) and an Orbitrap, a very high resolution mass spectrometer. The scientific life of our laboratory is organized around the three teams and the two thematic groups by regular meetings. This scale of organization is very efficient for the training of young scientists and for developing efficient internal collaborations. We also have regular seminars with invited speakers from all over the world (see Annex 3), as well as two annual one day meetings, one for the whole laboratory and one for PhD students, which are organized in a conference place in the mountains around Grenoble to increase the cohesion of the whole laboratory. Our laboratory council ( Conseil de laboratoire ), which is a general assembly due to the small size of the laboratory, meets regularly, once every two months and discusses all aspects of the laboratory policy. A direction team, composed of the director, the deputy director, the two administrative persons and the scientific team leaders, meets every month and the direction meets more frequently with the administrative staff to run the laboratory s everyday life. Technical staff is mutualised and works on scientific projects. Technical and administrative staff is managed in a transparent way for specific grants proposals and promotion policy. They meet annually with the director to evaluate their activity and establish professional priorities for the next year. Continuous training projects (see Annex 6) and promotion examinations are strongly encouraged by the direction. PhD students also have an annual meeting with the direction, for an evaluation of their thesis progress and to prepare their

5 3 professional future. Finally, get together meetings are organized several times per year and create a laboratory team spirit. The human resources of our laboratory have regularly increased during the last years. The attractive scientific life of our laboratory strongly contributed to increase the number of researchers during the last quadrennial with the recruitment of four young researchers (two MdC, one astronomer and one CR2 CNRS) and the mobility of two CNRS researchers coming from Orsay. However the number of technical and administrative staff (ITA CNRS: Engineers, Technicians, Administrative staff) stayed constant, as can be seen in the figure above. In order to face this situation, temporary personnel had to be hired and paid with contracts (CDDs). Furthermore, following the departure of our computer science engineer (spring 2009), we started to share the management of our technical staff with the Laboratoire d Astrophysique de Grenoble (LAOG). This allows to be more efficient and to face the task charges of our scientific projects. Let us note that our laboratory is young and dynamic, with an average age of 44.5 and 44 years old, for researchers and technical / administrative staff, respectively. Six out of the thirteen researchers have the ability for conducting PhD students (HDR) and four researchers plan to pass their examination within the next year. Almost all our former graduate students have been hired on academic positions in many different university laboratories or space agencies, and the youngest ones as postdoctorate fellows. A peculiarity of our laboratory is the very high number of young students, both undergraduate and graduate students, engineer and academic students, who are attracted by our laboratory and its reputation for excellent student formation. Researchers of our laboratory are strongly involved in teaching activities (see Annex 1) of Physics, Earth Sciences, as well as within the field of Planetary Sciences and remote sensing techniques. Lecturers (MdC) are responsible for several formation courses and are involved both in undergraduate and graduate courses of all levels. Most CNRS researchers give lectures for different types of students. Our laboratory is exceptionally active in outreach activities which involve most members of the laboratory. Let us cite for example the LPG collective outreach book on the Solar System ( Le Système Solaire revisité ) and the Planeterrella set up, designed to exemplify the principles of planetary aurorae to a broad public (see Annex 4). The PhD students also designed 3D projection models to show results on the Mars polar ice cap evolution with seasons to a broad audience. Our annual budget is about 500 Keuros, with only about 10% recurrent money ( soutien de base ) coming almost equally from CNRS and the Grenoble University. 90% of the budget is obtained for projects and financed by several sources. The diagram on the left shows the distribution of the total budget for was an exceptional year, because an additional

6 4 500 Keuros budget has been obtained by four different sources to buy a very high resolution mass spectrometer (Orbitrap). Contracts on the development of space instruments, analysis preparation, mission operations and recorded data analysis from the French Space Agency (CNES) are the main contribution to our budget. However, since 2007, new types of contracts significantly contribute to our budget, such as contracts from the Agence Nationale de la Recherche (ANR, 3 contracts, one being in common with LAOG) and from the European Space Agency (ESA). In 2010, we will receive significant financial support with four new contracts from the EU FP7 programme (Europlanet RI, which is the Planetary Sciences Infrastructure European Network in which we play an important role, Soteria, which is a network for Sun atmosphere interactions, VAMDC that coordinate laboratory spectroscopy database development, and a Marie Curie Individual research grant for V. Vuitton to help her reintegration in Europe after six years in the USA). In the frame of the development of next generation instruments for planetary missions, the LPG has developed and will extend partnership with industries: Thermo Fisher Scientific Society (San Jose, California) for the Orbitrap technology, Astrium UK and Thales Alénia Space for radars. In 2007 and 2008, with funding coming from the Ministère de la Recherche and OSUG, our laboratory area was extended by 300 m 2 (30% of the total surface), which have been renovated into spaces dedicated to experiments (Orbitrap laboratory and Consert radar electronics laboratories), as well as a meeting room and offices. We however already reach saturation of the space available during spring period, when young students are hosted. The digital network was also completely renovated. So since the beginning of 2009, our laboratory area is almost totally renovated on the whole last floor of the Physics D building. Concerning the safety policy of the laboratory (see Annex 6), we continued to have actions inside our laboratory to guarantee the best safety conditions of the staff, with a special care for the formation of all young scientists. However the safety of the building, in particular for fire hazards, is still very alarming. The University has planned to renovate our building with the necessary works which should start beginning of Concerning ethics, our laboratory pays a special attention in the recruitments. All the new recruited researchers made their thesis in another University. The new researchers who joined the LPG during the last four years are in an equal female/male ratio (3/3). We declared in our proposed personnel profiles, that personnel with a handicap are welcome. However our building cannot allow this for the moment. PhD charts and computer network ethical charts are strictly followed by everyone.

7 Organization Chart 5

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9 6 Detailed scientific Report by internal teams «Upper Planetary Atmospheres» (Hautes Atmosphères Planétaires) Team leader: Jean Lilensten Permanent scientific staff: M. Barthélémy, O. Dutuit, C. Lathuillère, J. Lilensten, F. Pitout, R. Thissen and V. Vuitton The team has for general objective the study of the evolution, composition, and dynamics of the upper planetary atmospheres. During the last 5 years, we published more than 80 papers in peer reviewed journals. The scientific activities are conducted around several themes in a coherent way. Characterization of the physico chemical states of the atmospheres and the interactions between the atmospheric layers [58, 64, 68, 85, 88 90, 93, 105, , H3 7, H11, H13 14, H17 18, H20 21, H27, H29] (8 invited papers) This new scientific activity started with the arrival in January 2007 of two physical chemists from the Laboratoire de Chimie Physique at the University Paris Sud. Thanks to the contribution of five funding agencies (including ANR), a very high resolution mass spectrometer (Orbitrap) was acquired in order to study the molecular growth in the ionosphere of Titan. This instrument constitutes a dedicated facility, installed in a renovated room with state of the art equipment. The instrument allows measuring kinetic constants and branching ratios of ion molecule reactions and analysing the composition of the Titan aerosols analogues (collab. LATMOS, paper in press). This facility is opened to other groups from the Grenoble Observatory (especially LGGE teams) and became a local research service. The new concept underlying this mass spectrometer is so powerful that we proposed it as a space instrument to the CNES agency. It has been accepted and entered the study phase along with the industrial developer Thermo Scientific and the LPC2E (Orléans). Laboratory simulations of the ionospheric chemistry as well as measurements of relevant kinetic parameters using specific experiments at synchrotron facilities (Elettra in Italy, Soleil) (paper in press) complement the effort. Finally, we contribute to the development of numerical models describing the photochemistry of the neutral and ionized species. V. Vuitton obtained a CNRS position (CR2) in 2008 to reinforce this team and one PhD student (J.Y. Bonnet) started his thesis in 2009 under the double supervision of R. Thissen and E. Quirico. The originality of this project attracted Pr. Roger Yelle (LPL Tholins mass analysis with the Orbitrap Arizona), who is one of the worldwide specialists of planetary atmospheres modelling and who was an invited professor from the Grenoble University during three months in 2008 (see the thematic group on Titan). In 2007, we organized a specific successful workshop dedicated to the Titan atmosphere: composition, dynamics and chemistry.

10 7 Characterization and quantification of the energy sources (electronic, ionic, cosmic EUV precipitation) and their effects (planetary space weather) [1 8, 11 16, 20 22, 28 29, 31 34, 38 39, 43, 46, 48, 55 56, 61, 65 66, 70 73, 78, 92, 94 95, 97, 103, 108, , 121, H2, H12, H15 16, H24, H28][ Thesis T1, T4, T8] (11 invited papers) Planetary high altitude atmospheres and ionospheres are dependent on solar EUV and high energy solar protons and cosmic rays. They also react to precipitating electrons and ions of lower energy that originate directly from the disturbed or quiet solar wind or indirectly through solar wind / magnetosphere interactions, when the planet has its own internal magnetic field. Such interactions are also a momentum source to the magnetospheric and ionospheric plasma through the convection electric field imposed to the magnetospheric cavity. At Earth, using CLUSTER satellite data, we have characterized the cusp regions where the solar wind plasma can enter into the magnetosphere, thanks to magnetic field reconnection. We have also studied the field aligned currents associated to dayside plasma injections at the altitude of CLUSTER and in the ionosphere using the SuperDARN chains of radars. We used the EISCAT radars to characterize the high latitude ionosphere and thermosphere and its response to strong and extreme solar events as the ones that occurred in October and May We have also shown that the response of the low to middle latitude thermosphere to solar wind perturbations was statistically underestimated by semi empirical models using either temperature measurements obtained on the UARS satellite or total density measurements deduced from accelerometer measurements performed on board the CHAMP satellite and we have proposed to use regional geomagnetic indices instead of planetary ones to better characterize the auroral energy inputs to the thermosphere in empirical models. Models of the Earth upper atmosphere, but also of planetary atmospheres, suffer from a poor characterization of the solar EUV spectrum which is usually based on the F10.7 solar index. We demonstrated how to retrieve the full solar spectrum through the observation of a reduced set of lines. From this research conducted in collaboration with LPC2E (Orléans), a space instrument is under feasibility study phase (CNES funding). In space weather, we have lead the largest European group (27 countries) and set the bases of the discipline in Europe (COST 724 action, ). This action was rated success story by the European Commission in In particular, we are at the origin of the European Space Weather Week (annual international meeting), and a major actor in the creation of the Belgium Solar Center of Excellence (10 researchers). From our efforts in model development, we predicted the existence of doubly charged ions in the ionospheres of Titan, Venus, Mars and Earth. These ions are present in low density, but may have an important effect on the chemistry and on the dynamics of the thermospheres. In collaboration with a laboratory of Norway (Oslo), we developed a photo polarimeter, with which we have discovered that the auroral thermospheric atomic oxygen red line is polarized. This result may have important impacts both for space weather (new observable of the geomagnetic activity) and planetary sciences. Indeed, the polarization direction depends on the magnetic and / or electric configuration, so that its measurement can give information on the magnetic and electric environments of the planet. In the case of Venus or Mars (with no intrinsic magnetic field), it may show how the interplanetary field wraps the planets. Following this discovery, we conducted original experiments for Mars and Venus (under way). We discovered the polarization of an H + 3 line in Jupiter (not yet published). We proposed to add photopolarimeters to several future space missions to Jupiter, Saturn and for exoplanets observation. More recently, we extended our model effort towards radiative transfer and cosmic ray effects in different atmospheres. Firstly, we showed the effect of an exoplanet atmosphere on a star spectrum and demonstrated that the deformation of the spectrum can reveal the presence of molecules in the planetary atmosphere. Secondly, we proposed an explanation for the source of the two haze layers

11 8 in Titan atmosphere: the lowest layer would be due to the precipitation of cosmic rays and the detached one from the Saturn magnetospheric protons precipitation. This activity was reinforced by the arrival of one researcher (F. Pitout, CNAP). We conducted three PhD theses (F. Culot, C. Simon, G. Gronoff), one is underway (H. Ménager) and one is co directed with the LPC2E, Orléans (G. Cessateur). We also had several master students (M2R).

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13 9 «Surfaces, subsurfaces and cometary nuclei: radar teledetection (Surfaces, Sub surface et noyaux cométaires: Télédétection Radar) Team leader: Wlodek Kofman Permanent scientific staff: A. Hérique and W. Kofman This team studies surfaces and sub surfaces of the solar system objects using the radar techniques. It is the originality and the strength of the team, internationally recognized. The team works on all the present and future space projects of low frequency radars in collaboration with international teams (US, Japan, Europe). Small bodies The preparation of the Rosetta mission is an essential task for our team, as we are responsible for the Consert radar experiment (PI W.Kofman) [44]. In order to prepare the CONSERT scientific return and data analysis, we developed numerical models of cometary nuclei (interior and surface). The cometary surface is described by spherical harmonics decomposition, the interior structure is deduced from primordial aggregation and the thermal evolution is deduced from numerical simulations. The technical preparation of the CONSERT operation requires regular tests of the instrument, preparation for the data analysis, as well as the development of the preparation of the cometary operations. For this we developed software which includes 3D simulations of the signal propagation through the comet nucleus, simulation of the signal reception on the orbit, the analysis of the best configuration between the lander and the orbiter, as well as the data inversion. Surface and subsurface studies: Mars The SHARAD and MARSIS radars on board of the Mars Reconnaissance Orbiter and Mars Express space missions respectively, are currently observing the surface and the subsurface of Mars. In his PhD thesis, J. Mouginot developed the data processing and geophysical interpretation of radar signals. As a by product of the data analysis we derived the total electron content of the ionosphere (TEC) and showed its correlation with the crustal magnetic field [52, 74, 99]. The first measurement of the thickness of the south polar layer deposits and the proof that the water ice is very pure were deduced from radar data [51, 91]. The data analysis of the water ice layer thickness was made by J. Mouginot [51]. Another outstanding result is the measurement of the thickness of the CO 2 layer of the south residual cap using the measurements of the radar reflectivity [99]. Two other very important articles, recently submitted to JGR and Nature (Mouginot et al.), give an interpretation of the reflectivity of the surface. The nice progress benefits from the long term work of our team in the field. Radar view of the Northern polar cap of Mars showing its stratified structure (taken by the SHARAD radar sounder on board the Mars Reconnaissance Orbiter).

14 10 Surface and subsurface studies: Moon For the past two years we have been having a close collaboration with the Sendai University group of Pr. Ono working on the Lunar Radar Sounder data from the Japanese Kaguya lunar mission. We are presently working on these data, analyzing the layers in the subsurface of the lunar mares. Instruments development The team is working on the future radar projects for space missions. A. Hérique is responsible for the Wisdom radar instrument project for the Exomars mission. The ground penetrating radar has been selected with a French PI (V. Ciarletti, LATMOS). Our team is in charge of the on board software and of the "Electronic Ground Support Equipment". The implication of the future laboratory in this project will be very important. We are also involved in the proposal for Cosmic Vision EJSM mission project towards the Jupiter System. Radars are planned on the payloads of both the Jupiter Europa Orbiter (NASA) and the Jupiter Ganymede Orbiter (ESA). We are participating in the answer to the AO with Jet Propulsion Laboratory (USA) and Italian colleagues. This project will involve colleagues from other teams of our laboratory. Radar theory and electromagnetism We continue the study of radar methods and of the propagation of electromagnetic waves in the solid media. This activity triggers the proposal of new instruments. The study of the polarimetric response of buried targets is directly applicable for Wisdom data inversion (F. Bucci PhD thesis). The inversion of the object shape is more prospective. Contracts Our group is mainly funded by CNES and ESA for the Consert, Marsis, Sharad, Kaguya and Wisdom radar activities.

15 11 Solid Molecular Matter of the Solar System (Matière Moléculaire Solide du Système Solaire) Team leader: Bernard Schmitt Permanent scientific staff: P. Beck, S. Douté, E. Quirico and B. Schmitt Two main scientific axes define our studies of solid molecular phases at the surface and inside solar system solar bodies: (i) understanding the primitive organic matter origin and evolution; (ii) deciphering the state and evolution of ices and mineral hydration at the surface of planets and satellites. The determination of the chemical and isotopic compositions, physical and textural states of ices, hydrated mineral and organic phases, as well as their spatial distribution and temporal evolutions in Solar System objects allows the study of their origin, formation and evolution at different time scales. It also provides important information on the dynamics of these objects, such as hydrothermal processes on asteroids or climatic evolution of planets such as Mars. To retrieve all this information we use different but complementary approaches: (i) experimental measurements and simulations (spectroscopy, thermodynamics, photochemistry, ) on ices and mineral hydration; (ii) laboratory simulations and extraterrestrial sample analysis (chemical, structural, spectral characterizations) focused on primitive organic matter; (iii) development of analysis tools for remote sensing imaging spectroscopy observations of surfaces; and (iv) analysis and interpretation of spectroscopic remote sensing data of planetary surfaces, currently focused on Mars Primitive organic matter Pristine chondrites, interplanetary dusts and cometary grains contain primitive insoluble organic matter (IOM). The place and chemical processes which led to its formation, along with its further evolution in the solar nebula and the parent body are crucial questions actively debated. They provide potentially clues on the complex organic chemistry which lies from molecular clouds to planetary disks, as well as dynamic insights on the solar nebula like radial mixing, etc. Our studies along the last four years first concern the effect of post accretion processes on the IOM. This is a crucial issue as IOM should be considered as an end product, and the way it was transformed along its long and complex history is a prerequisite to recover pristine information. We definitely evidenced that IOM is drastically transformed by thermal metamorphism on the parent bodies [40], and we proposed a new technique and a new classification scheme decoupling thermal and aqueous events. A striking implication is the reassessment of the primitiveness of CV chondrites, and a reinterpretation of some of their petrologic and mineralogic features earlier assigned to nebular processes [26, 18]. These works have also more general implementation in carbon thermometry, either on extraterrestrial or terrestrial carbonaceous rocks [107]. We also focused on unmetamorphosed chondrites, and showed that aqueous alteration has also effects on IOM composition through oxidation processes. Our studies on the most pristine samples, interplanetary dusts and Antarctic micro meteorites, have revealed the presence of an ubiquitous polyaromatic carbon material, fairly but not strictly similar to chondrites IOMs. For the first time clues on the phases bearing nitrogen were obtained. Finally, our results support the idea that the IOM precursors suffered from pre accretion heating in the solar nebula.

16 12 Financial support was obtained from CNES (Stardust and Rosetta programs), ANR FORCOMs (with LAOG) and UJF/TUNES. Four PhD theses (L. Bonal, F.R. Orthous Daunay, A. Ratajczak J.Y. Bonnet) and one UJF post doc (G. Montes Hernandez) contributed to this activity. P. Beck (MCF recruited in 2007) is an important support for this activity. Titan Titan is a very interesting object in regard to the chemical complexity of its atmosphere and surface. We focused our studies on the composition of the surface and of the stratospheric aerosols [9, 23, 27, 36, 69] by acquiring infrared spectra of several simple and complex organics and investigating their photometric properties [24, 77]. The analysis of the Titan surface spectra recorded by the DISR instrument (Huygens mission) showed the presence of liquid CH 4 and C 2 H 6 mixed with ice and organic matter. The understanding of the cycle of these organic liquids led us to propose a trapping mechanism of the hydrocarbons in the porous cryovolcanic sub surface of Titan [75]. In this context (and for wider planetary purposes), we performed a bibliographic compilation of the vapor pressure of the main planetary molecules in the solid phase [115] and started experimental studies of the equilibrium pressures of clathrates hydrates and their spectral signatures [117]. Financial support : CNES (Cassini program), GdR Exobiologie and Franco Israel collaboration. Three Post Doctoral fellows worked on these subjects (J. M. Bernard, N. Fray and U. Marboeuf). Mars The spatial and temporal distributions of CO 2 and water on Mars in their different physical states (seasonal condensations, polar caps, atmosphere, clouds ) constrain the seasonal exchange cycles of these molecules between the surface of Mars and its CO 2 atmosphere. They can provide precious information for the understanding of the current and past climatic cycles. We used the tools coming from our modelling and methodological activity to analyse Mars remote sensing data (OMEGA@MEX and CRISM@MRO) [25, 86]. Very significant results have been obtained, notably on the quantitative mapping of the properties of the CO 2 and H 2 O ices, making up the upper few centimetres of the permanent southern cap [42, 122]. In addition, we have been monitoring with an unprecedented accuracy the time and space evolution of the seasonal CO 2 and H 2 O icy deposits during their spring recession in both hemispheres [10] with a particular focus on regions presenting active gas and dust geysers [30, 45]. We have analysed the factors that control this recession in the South Pole region [102]. We also contributed to atmospheric and aerosols studies [35, 47, 104]. A large part of our work is focused on the understanding of the present and past Martian water cycle. The first step is to estimate the volume of water reservoirs and the kinetics of exchanges between them. The least constrained reservoir is the Martian regolith, in which water can be present as ice, hydrated minerals and water adsorbed on minerals grains. In order to study water adsorption in Martian conditions, the SERAC environmental cell was developed to quantify the amount of water that adsorbs under Martian conditions [106], the spectral behaviour and the origin of the 3 µm band [79, 80, 106] and the kinetic of water exchange between surface and atmosphere (Beck et al., submitted).

17 13 Spectral classification of CO2 frost seasonal deposits for high southern latitudes of Mars. Financial support comes from CNES (Mars Express program), PNP. Three PhD theses contributed (F. Schmidt, A. Pommerol, T. Appéré). P. Beck (MCF) has been recruited in 2007 to mostly work on this activity. Development of remote sensing tools Our team is the principal coordinator of a multidisciplinary project (INRIA Rhône Alpes, GIPSA Lab INPG, LPG) entitled Visualization and analysis of multi dimensional hyperspectral images in Astrophysics that started in 2008 and will end in We organize our research and developments according to four work packages (WP): (i) Statistical image processing detects, delineates, and extracts planetary surface units by classifying hyperspectral images. (ii) Physical models pertaining to radiative transfer in planetary surfaces and atmospheres first generate well calibrated synthetic data used to validate the statistical methods. Second (iii) inversion algorithms can reverse the models in order to estimate the physical properties of the objects of interest from hyperspectral images. (iv) a web service provides a powerful interface for data model generation and management of image collections. Among others, one significant result is the development of original methods for the physical analysis of a huge number of spectra [53, 76, 122]. One engineer and one PhD (X. Ceamanos), financed by ANR and CNES, work on this project at LPG. Development of databases We also started to develop a web database service GhoSST on experimental spectroscopy and thermodynamics of solids in order to provide access to our laboratory data to the whole community (details in the OSUG observation services report).

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19 14 Thematic group: «Mars» Group leader: Pierre Beck The Mars thematic group consists of PhD students and researchers from the three research teams of the LPG. Bi monthly meetings are organized during which informal talks are given by group members or external researchers. Beyond the thematic aspect, specific equipments have been bought through the thematic group in the form of a GIS station and the associated software. The dataset available on this platform consists of public data from a variety of sources, proprietary data and data products from the LPG. The platform facilitates dataset exploration and comparison and has led to successful scientific collaboration between researchers from various fields within the LPG. Discussion initiated during a Mars thematic group meeting on particulars scarps observed in the Mars south polar caps have led to a presentation at COSPAR that includes author from the Subsurface and the Molecular Matter team (Grima et al., 2008). A publication is in preparation on this subject. The observations of Mars surface reflectivity by the MARSIS radar have been compared to a model of ice stability in the sub surface. This work has enabled to interpret the strong reflectivity drop observed poleward of 50 N as the onset of ice occurrence within the regolith. A publication has been submitted on this subject (Mouginot et al.) that includes authors from the Surfaces and Subsurfaces and the Molecular Matter teams. This study has opened great perspectives in the use of radar reflectivity and will be pursued with observations from the SHARAD radar. Finally, a collaboration took place between members of the Upper Planetary Atmospheres team and researchers from the Surfaces and Sub surfaces team. Total electron contents (TEC) derived from the SHARAD signal distortion have been compared with energetic particles fluxes measured by the ASPERA instrument and to UV emissions detected by the SPICAM instrument. These studies have led to the characterisation of aurorae on Mars [32, 71]. Thematic group: Titan Group leader: Roland Thissen At the beginning of the quadrennial , LPG was already strongly involved in projects related to Titan. Works on ionospheric chemistry [12,13], surface spectroscopy [9,23,27,36] and aerosol analogues analysis [24] were performed by the different LPG groups, stimulated by the Cassini Huygens exploration of Titan. This mission revealed the extreme complexity and evolution of matter in the Titan environment. We therefore organized a thematic group (5 researchers and 1 PhD student) around the description of the cycle of matter, from its release as simple molecules, through its activation in the atmosphere, its growth in ionosphere, and finally its sedimentation as aerosols at the satellite surface. To this end, an interdisciplinary project (ChimieTitan+) was set up. It relies on a mass spectrometer at ultra high resolution that is used for the characterization of ion molecule reactions and for aerosol analogues analysis. It has been funded by the ANR, the OPV program, the Rhône Alpes Region, and CNES in 2007 for the purchase of the Orbitrap instrument in The Region granted a post doc for V. Vuitton who obtained a CNRS position in She will extend the group efforts towards the chemistry of negatively charged species, a project that was triggered by

20 15 exceptional results from Cassini showing very big anions in the ionosphere. She obtained a reintegration grant with the Marie Curie EU FP7 Programme. The collaborative work has started to produce results: (i) the deposition of energy in the whole atmosphere is part of the PhD thesis of G. Gronoff [ accepted papers], (ii) new kinetic models of Titan in situ ionospheric activity are proposed [58,68,88,89,93,105 + Thissen et al. in press], (iii) surface thermodynamics and spectroscopy [60,69,75], laboratory characterization of aerosol analogues [77,81 + Carrasco et al. in press] and laboratory simulations of photon induced chemistry are underway. The group organized five workshops on topics related to the cycle of matter in Titan, and its characterization. A very active international collaboration is maintained with Pr. R. Yelle (LPL, Univ. Arizona) who came in the fall 2008 as an invited professor of the Grenoble University. Within this collaboration, we developed kinetic models to interpret the experimental results and specific tools for analysis of the complex mass spectra recorded on the aerosols analogues. This work, even though recent, is already internationally recognized. R. Thissen became the only European associated scientist for the INMS instrument of the Cassini mission and the work has been presented as invited talks in the best international conferences of Planetary Sciences (EPSC, EGU, AOGS ). Several of us were invited to become members of the NAI/NASA group on astrobiology. It also led to the strong implication of the team in the TandEM (TSSM) project of new mission towards Titan [87].