Examinando por Autor "Forget, F."

Mostrando 1 - 8 de 8

Acceso Abierto
A stringent upper limit of 20 pptv for methane on Mars and constraints on its dispersion outside Gale crater
(EDP Sciences, 2021-07-20) Montmessin, F.; Korablev, O. I.; Trokhimovskiy, A.; Lefèvre, F.; Fedorova, A. A.; Baggio, L.; Irbah, A.; Lacombe, G.; Olsen, K. S.; Braude, A. S.; Belyaev, D. A.; Alday, J.; Forget, F.; Daerden, F.; Pla García, J.; Rafkin, S.; Wilson, T. F.; Patrakeev, A.; Shakun, A.; Bertaux, J. L.; Agence Nationale de la Recherche (ANR); Natural Sciences and Engineering Research Council of Canada (NSERC); UK Space Agency; Science and Technology Facilities Council (STFC); Montmessin, F. [0000-0002-4187-1457]; Korablev, O. I. [0000-0003-1115-0656]; Trokhimovskiy, A. [0000-0003-4041-4972]; Lefèvre, F. [0000-0001-5294-5426]; Fedorova, A. A. [0000-0002-4176-2955]; Baggio, L. [0000-0002-9263-4937]; Irbah, A. [0000-0003-3265-3148]; Olsen, K. S. [0000-0002-2173-9889]; Braude, A. M. [0000-0003-2437-2151]; Belyaev, D. A. [0000-0003-1123-5983]; Alday, J. [0000-0003-1459-3444]; Forget, F. [0000-0002-3262-4366]; Pla García, J. [0000-0002-8047-3937]; Rafkin, S. [0000-0001-7464-1319]
Context. Reports on the detection of methane in the Martian atmosphere have motivated numerous studies aiming to confirm or explain its presence on a planet where it might imply a biogenic or more likely a geophysical origin. Aims. Our intent is to complement and improve on the previously reported detection attempts by the Atmospheric Chemistry Suite (ACS) on board the ExoMars Trace Gas Orbiter (TGO). This latter study reported the results of a campaign that was a few months in length, and was significantly hindered by a dusty period that impaired detection performances. Methods. We unveil 640 solar occultation measurements gathering 1.44 Martian years worth of data produced by the ACS. Results. No methane was detected. Probing the clear northern summer season allowed us to reach 1σ upper limits of around 10 pptv (20 pptv at 2σ), with an annual mean of the smallest upper limits of 20 pptv. Upper limits are controlled by the amount of dust in the atmosphere, which impairs detection performance around the equator and during the southern spring and summer seasons. Observations performed near Gale crater yielded 1σ upper limits of up to four times less than the background values measured by the Curiosity rover during the corresponding seasons. Conclusions. Reconciliation of the absence of methane in the TGO spectra with the positive detections by Curiosity is even more difficult in light of this annual survey performed by ACS. Stronger constraints are placed on the physical and chemical mechanism capable of explaining why the mean of the best overall upper limits of ACS is ten times below the smallest methane abundances measured by Curiosity.
Acceso Abierto
A Study of Daytime Convective Vortices and Turbulence in the Martian Planetary Boundary Layer Based on Half-a-Year of InSight Atmospheric Measurements and Large-Eddy Simulations
(American Geophysical Union: Advancing Earth and Space Science, 2021-01-12) Spiga, A.; Murdoch, N.; Lorenz, R.; Forget, F.; Newman, C. E.; Rodríguez, Sébastien; Pla García, J.; Viúdez Moreiras, Daniel; Banfield, D.; Perrin, C.; Mueller, N. T.; Lemmon, M. T.; Millour, E.; Banerdt, W. B.; Agencia Estatal de Investigación (AEI); Spiga, A. [0000-0002-6776-6268]; Murdoch, N. [0000-0002-9701-4075]; Lorenz, R. [0000-0001-8528-4644]; Forget, F. [0000-0002-3262-4366]; Newman, C. [0000-0001-9990-8817]; Rodríguez, S. [0000-0003-1219-0641]; Pla García, J. [0000-0002-8047-3937]; Viúdez Moreiras, D. [0000-0001-8442-3788]; Perrin, C. [0000-0002-7200-5682]; Mueller, N. T. [0000-0001-9229-8921]; Lemmon, M. [0000-0002-4504-5136]; Millour, E. [0000-0003-4808-9203]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Studying the atmospheric planetary boundary layer (PBL) is crucial to understand the climate of a planet. The meteorological measurements by the instruments onboard InSight at a latitude of 4.5°N make a unique rich data set to study the active turbulent dynamics of the daytime PBL on Mars. Here we use the high-sensitivity continuous pressure, wind, and temperature measurements in the first 400 sols of InSight operations (from northern late winter to midsummer) to analyze wind gusts, convective cells, and vortices in Mars’ daytime PBL. We compare InSight measurements to turbulence-resolving large-eddy simulations (LES). The daytime PBL turbulence at the InSight landing site is very active, with clearly identified signatures of convective cells and a vast population of 6,000 recorded vortex encounters, adequately represented by a power law with a 3.4 exponent. While the daily variability of vortex encounters at InSight can be explained by the statistical nature of turbulence, the seasonal variability is positively correlated with ambient wind speed, which is supported by LES. However, wind gustiness is positively correlated to surface temperature rather than ambient wind speed and sensible heat flux, confirming the radiative control of the daytime Martian PBL; and fewer convective vortices are forming in LES when the background wind is doubled. Thus, the long-term seasonal variability of vortex encounters at the InSight landing site is mainly controlled by the advection of convective vortices by ambient wind speed. Typical tracks followed by vortices forming in the LES show a similar distribution in direction and length as orbital imagery.
Acceso Abierto
Effects of a Large Dust Storm in the Near‐Surface Atmosphere as Measured by InSight in Elysium Planitia, Mars. Comparison With Contemporaneous Measurements by Mars Science Laboratory
(American Geophysical Union: Advancing Earth and Space Science, 2020-08-11) Viúdez Moreiras, Daniel; Newman, C. E.; Forget, F.; Lemmon, M. T.; Banfield, D.; Spiga, A.; Lepinette, A.; Rodríguez Manfredi, J. A.; Gómez Elvira, J.; Pla García, J.; Muller, N.; Grott, M.; TWINS/InSight team; Agencia Estatal de Investigación (AEI); Centre National D'Etudes Spatiales (CNES); Spiga, A. [0000-0002-6776-6268]; Lemmon, M. [0000-0002-4504-5136]; Newman, C. [0000-0001-9990-8817]; Pla garcía, J. [0000-0002-8047-3937]; Mueller, N. [0000-0001-9229-8921]
NASA's InSight landed in Elysium Planitia (~4.5°N,136°E) at Ls ~ 296° (November 2018), right after the decay of the 2018 Global Dust Storm (GDS) and before the onset of the 2019 Large Dust Storm (LDS) at Ls ~ 320° (January 2019). InSight's cameras observed a rise in the atmospheric opacities during the storm from ~0.7 to ~1.9, similarly to contemporaneous measurements by Curiosity in Gale crater. Pressure tides were strongly affected at the locations of InSight and Curiosity. In particular, the diurnal pressure mode experienced an abrupt increase during the onset of the LDS, similar to that measured by Curiosity, most likely due to longitudinally asymmetric dust loading. Later, the dust was redistributed around the planet and the semidiurnal mode evolved according to dust opacity in both missions. Before and after the onset of the storm, the observed wind patterns resulted from the interaction between regional and local slope flows induced by topography, which all produced a diurnal perturbation superimposed on a mean flow, dominated by the Hadley cell but with modifications due to channeling effects from the regional topography. However, the onset of the LDS modified this to a scenario consistent with enhanced tidal flows. The local air temperatures are strongly perturbed by the lander's thermal effects, and their retrieval significantly depends on wind patterns, which changed during the course of the dust storm. Observations suggest a decrease in convective vortices during the dust storm; however, vortex activity remained strong during the storm's onset due to the increase in wind speeds.
Acceso Abierto
Lander and rover histories of dust accumulation on and removal from solar arrays on Mars
(Elsevier, 2021-11-01) Lorenz, R. D.; Martínez, G. M.; Spiga, A.; Vicente Retortillo, Á.; Newman, C. E.; Murdoch, N.; Forget, F.; Millour, E.; Pierron, T.; National Aeronautics and Space Administration (NASA); Agence Nationale de la Recherche (ANR); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The degradation in electrical output of solar arrays on Mars landers and rovers is reviewed. A loss of 0.2% per Sol is typical, although observed rates of decrease in ‘dust factor’ vary between 0.05% and 2% per Sol. 0.2%/Sol has been observed throughout the first 800 Sols of the ongoing InSight mission, as well as the shorter Mars Pathfinder and Phoenix missions. This rate was also evident for much of the Spirit and Opportunity missions, but the degradation there was episodically reversed by cleaning events due to dust devils and gusts. The enduring success of those rover missions may have given an impression of the long-term viability of solar power on the Martian surface that is not globally-applicable: the occurrence of cleaning events with an operationally-useful frequency seems contingent upon local meteorological circumstances. The conditions for significant cleaning events have apparently not been realized at the InSight landing site, where, notably, dust devils have not been detected in imaging. Optical obscuration by dust deposition and removal has also been observed by ultraviolet sensors on Curiosity, with a similar (but slightly higher) degradation rate. The observations are compared with global circulation model (GCM) results: these predict a geographically somewhat uniform dust deposition rate, while there is some indication that the locations where cleaning events were more frequent may be associated with weaker background winds and a deeper planetary boundary layer. The conventional Dust Devil Activity metric in GCMs does not effectively predict the different dust histories.
Acceso Abierto
Multi-model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region
(Springer Link, 2021-02-08) Newman, C. E.; Torres Juárez, M.; Pla García, J.; Wilson, R. J.; Lewis, S. R.; Neary, L.; Kahre, M. A.; Forget, F.; Spiga, A.; Richardson, M. L. A.; Daerden, F.; Bertrand, T.; Viúdez Moreiras, Daniel; Sullivan, Robert; Sánchez Lavega, A.; Chide, B.; Rodríguez Manfredi, J. A.; National Aeronautics and Space Administration (NASA); European Space Agency (ESA); Centre National D'Etudes Spatiales (CNES); Sánchez Lavega, Á. [0000-0001-7234-7634]; Lewis, S. [0000-0001-7237-6494]
Nine simulations are used to predict the meteorology and aeolian activity of the Mars 2020 landing site region. Predicted seasonal variations of pressure and surface and atmospheric temperature generally agree. Minimum and maximum pressure is predicted at Ls∼145∘ and 250∘, respectively. Maximum and minimum surface and atmospheric temperature are predicted at Ls∼180∘ and 270∘, respectively; i.e., are warmest at northern fall equinox not summer solstice. Daily pressure cycles vary more between simulations, possibly due to differences in atmospheric dust distributions. Jezero crater sits inside and close to the NW rim of the huge Isidis basin, whose daytime upslope (∼east-southeasterly) and nighttime downslope (∼northwesterly) winds are predicted to dominate except around summer solstice, when the global circulation produces more southerly wind directions. Wind predictions vary hugely, with annual maximum speeds varying from 11 to 19 ms−1 and daily mean wind speeds peaking in the first half of summer for most simulations but in the second half of the year for two. Most simulations predict net annual sand transport toward the WNW, which is generally consistent with aeolian observations, and peak sand fluxes in the first half of summer, with the weakest fluxes around winter solstice due to opposition between the global circulation and daytime upslope winds. However, one simulation predicts transport toward the NW, while another predicts fluxes peaking later and transport toward the WSW. Vortex activity is predicted to peak in summer and dip around winter solstice, and to be greater than at InSight and much greater than in Gale crater.
Restringido
The atmosphere of Mars as observed by InSight.
(Nature Research Journals, 2020-02-24) Banfield, D.; Spiga, A.; Newman, C. E.; Forget, F.; Lemmon, M. T.; Lorenz, R.; Murdoch, N.; Viúdez Moreiras, Daniel; Pla García, J.; García, R. F.; Lognonné, P.; Karatekin, Özgür; Perrin, C.; Martire, L.; Teanby, N.; Van Hove, B.; Maki, Justin N.; Kenda, B.; Mueller, N. T.; Rodriguez, Sébastien; Kawamura, T.; McClean, J. B.; Stott, A. E.; Charalambous, C.; Millour, E.; Johnson, C. L.; Mittelholz, A.; Määttänen, A.; Lewis, S. R.; Clinton, J.; Stähler, S. C.; Ceylan, S.; Giardini, D.; Warren, T.; Pike, W. T.; Daubar, I.; Golombek, M.; Rolland, L.; Widmer Schnidrig, R.; Mimoun, D.; Beucler, E.; Jacob, A.; Lucas, A.; Baker, M.; Ansan, V.; Hurst, K.; Mora Sotomayor, L.; Navarro, Sara; Torres, J.; Lepinette, A.; Molina, A.; Marín Jiménez, M.; Gómez Elvira, J.; Peinado, V.; Rodríguez Manfredi, J. A.; Carchic, B. T.; Sackett, S.; Russell, C. T.; Spohn, T.; Smrekar, S. E.; Banerdt, W. B.; Agence Nationale de la Recherche (ANR); Määttänen, A. [0000-0002-7326-8492]; Martire, L. [0000-0002-9402-6150]; Rodríguez Manfredi, J. A. [0000-0003-0461-9815]; Lognonné, P. [0000-0002-1014-920X]; Rodríguez, S. [0000-0003-1219-0641]; Spiga, A. [0000-0002-6776-6268]; Perrin, C. [0000-0002-7200-5682]; Molina, A. [0000-0002-5038-2022]; Rodríguez Manfredi, J. A. [0000-0003-0461-9815]; García, R. [0000-0003-1460-6663]; Murdoch, N. [0000-0002-9701-4075]; Lorenz, R. [0000-0001-8528-4644]; Mittelholz, A. [0000-0002-5603-7334]; Kawamura, T. [0000-0001-5246-5561]; Widmer Schnidrig, R. [0000-0001-9698-2739]; McClean, J. [0000-0002-7863-0120]; Mueller, N. [0000-0001-9229-8921]; Lewis, S. [0000-0001-7237-6494]; Teanby, N. [0000-0003-3108-5775]; Warren, T. [0000-0003-3877-0046]; Milliour, E. [0000-0003-4808-9203]; Lemmon, M. [0000-0002-4504-5136]; Clinton, J. [0000-0001-8626-2703]; Ceylan, S. [0000-0002-6552-6850]; Banfield, D. [0000-0003-2664-0164]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The atmosphere of Mars is thin, although rich in dust aerosols, and covers a dry surface. As such, Mars provides an opportunity to expand our knowledge of atmospheres beyond that attainable from the atmosphere of the Earth. The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) lander is measuring Mars’s atmosphere with unprecedented continuity, accuracy and sampling frequency. Here we show that InSight unveils new atmospheric phenomena at Mars, especially in the higher-frequency range, and extends our understanding of Mars’s meteorology at all scales. InSight is uniquely sensitive to large-scale and regional weather and obtained detailed in situ coverage of a regional dust storm on Mars. Images have enabled high-altitude wind speeds to be measured and revealed airglow—faint emissions produced by photochemical reactions—in the middle atmosphere. InSight observations show a paradox of aeolian science on Mars: despite having the largest recorded Martian vortex activity and dust-devil tracks close to the lander, no visible dust devils have been seen. Meteorological measurements have produced a catalogue of atmospheric gravity waves, which included bores (soliton-like waves). From these measurements, we have discovered Martian infrasound and unexpected similarities between atmospheric turbulence on Earth and Mars. We suggest that the observations of Mars’s atmosphere by InSight will be key for prediction capabilities and future exploration.
Restringido
The DREAMS experiment flown on the ExoMars 2016 mission for the study of Martian environment during the dust storm season
(Elsevier, 2018-02-01) Bettanini, C.; Esposito, F.; Debei, S.; Molfese, C.; Colombatti, G.; Aboudan, A.; Brucato, J. R.; Cortecchia, F.; Di Achille, G.; Guizzo, G. P.; Friso, Enrico; Ferri, F.; Marty, Laurent; Mennella, V.; Molinaro, R.; Schipani, P.; Silvestro, S.; Mugnuolo, R.; Pirrotta, S.; Marchetti, Edoardo; Ari-Matti, H.; Montmessin, F.; Wilson, Colin; Arruego, I.; Abbaki. S.; Bellucci, G.; Berthelier, J. J.; Calcutt, S.; Forget, F.; Genzer, M.; Gilbert, Pierre; Haukka, H.; Jiménez, Juan J.; Jiménez, Salvador; Josset, J. L.; Karatekin, Özgür; Landis, G.; Lorenz, Ralph; Martínez Oter, J.; Möhlmann, D.; Moirin, D.; Palomba, E.; Patel, M.; Pommereau, J. P.; Popa, C. I.; Rafkin, S.; Rannou, P.; Rennó, N. O.; Schmidt, W.; Simoes, F.; Spiga, A.; Valero, F.; Vázquez, L.; Apéstigue, Víctor; Agenzia Spaziale Italiana (ASI); Istituto Nazionale di Astrofisica (INAF)
"The DREAMS (Dust characterization, Risk assessment and Environment Analyser on the Martian Surface) instrument on Schiaparelli lander of ExoMars 2016 mission was an autonomous meteorological station designed to completely characterize the Martian atmosphere on surface, acquiring data not only on temperature, pressure, humidity, wind speed and its direction, but also on solar irradiance, dust opacity and atmospheric electrification; this comprehensive set of parameters would assist the quantification of risks and hazards for future manned exploration missions mainly related to the presence of airborne dust. Schiaparelli landing on Mars was in fact scheduled during the foreseen dust storm season (October 2016 in Meridiani Planum) allowing DREAMS to directly measure the characteristics of such extremely harsh environment. DREAMS instrument’s architecture was based on a modular design developing custom boards for analog and digital channel conditioning, power distribution, on board data handling and communication with the lander. The boards, connected through a common backbone, were hosted in a central electronic unit assembly and connected to the external sensors with dedicated harness. Designed with very limited mass and an optimized energy consumption, DREAMS was successfully tested to operate autonomously, relying on its own power supply, for at least two Martian days (sols) after landing on the planet. A total of three flight models were fully qualified before launch through an extensive test campaign comprising electrical and functional testing, EMC verification and mechanical and thermal vacuum cycling; furthermore following the requirements for planetary protection, contamination control activities and assay sampling were conducted before model delivery for final integration on spacecraft. During the six months cruise to Mars following the successful launch of ExoMars on 14th March 2016, periodic check outs were conducted to verify instrument health check and update mission timelines for operation. Elaboration of housekeeping data showed that the behaviour of the whole instrument was nominal during the whole cruise. Unfortunately DREAMS was not able to operate on the surface of Mars, due to the known guidance anomaly during the descent that caused Schiaparelli to crash at landing. The adverse sequence of events at 4 km altitude anyway triggered the transition of the lander in surface operative mode, commanding switch on the DREAMS instrument, which was therefore able to correctly power on and send back housekeeping data. This proved the nominal performance of all DREAMS hardware before touchdown demonstrating the highest TRL of the unit for future missions. The spare models of DREAMS are currently in use at university premises for the development of autonomous units to be used in cubesat mission and in probes for stratospheric balloons launches in collaboration with Italian Space Agency."
Acceso Abierto
The EChO science case
(Springer Link, 2015-11-29) Tinetti, G.; Drossart, P.; Eccleston, P.; Hartogh, P.; Isaak, K.; Linder, M.; Lovis, C.; Micela, G.; Olliver, M.; Puig, L.; Ribas, I.; Schrader, J. R.; Scholz, A.; Watkins, C.; Maillard, J. P.; Abreu, M.; Glasse, A.; Testi, L.; Doel, P.; Magnes, W.; Licandro Goldaracena, J.; Wawer, P.; Zapatero Osorio, M. R.; Decin, L.; Sánz Forcada, J.; Vakili, F.; Aylward, A.; Swain, M.; Sozzetti, A.; Filacchione, G.; Delgado Mena, E.; Read, P.; Lognonné, P.; Irshad, R.; Coates, A.; Cecchi Pestellini, C.; Thrastarson, H.; Brown, L.; Guillot, T.; Strazzulla, G.; Barstow, J. K.; Budaj, J.; Morgante, G.; Pietrzak, R.; Leconte, J.; Hersant, F.; De Sio, A.; Grassi, D.; Selsis, F.; Jarchow, C.; Fouqué, P.; Del Vecchio, C.; Tennyson, J.; Cassan, A.; Fernández Hernández, Maite; Burleigh, M. R.; Cordier, D.; De Witt, J.; Pagano, I.; Ray, T.; Gambicorti, L.; Palla, F.; Maldonado, J.; Biondi, D.; Eiroa, C.; Winek, W.; Ade, P.; Villaver, E.; Temple, J.; Gear, W.; Thompson, S.; Dominic, C.; Galand, M.; Focardi, M.; Cockell, C.; Pace, E.; Dorfi, E.; Bryson, I.; Cavarroc, C.; Pilat Lohinger, E.; Smith, A.; Eymet, V.; MacTavish, C.; Morales, J. C.; Gómez, H.; Stamper, R.; Esposito, M.; Andersen, A.; Azzollini, R.; Maxted, P.; Allende Prieto, C.; Nelson, R.; Gillon, M.; Achilleos, N.; Buchhave, L. A.; Fabrizio, N.; Ciaravella, A.; Claudi, R.; Damasso, M.; Bordé, P.; Figueira, P.; Rickman, H.; Rees, J. M.; Sitek, P.; Fossey, S.; Bakos, G.; Pascale, E.; Laken, B.; Soret, L.; Femenía Castella, B.; Allard, F.; Amado, P. J.; Luzzi, D.; Colomé, J.; Galand, M.; Lammer, H.; Bonford, B.; López Valverde, M. A.; Kerins, E.; Yung, Y.; Espinoza Contreras, M.; Irwin, P.; Herrero, E.; Wright, G.; Guàrdia, J.; Banaszkiewicz, M.; Hoogeeven, R.; Alcala, J.; Guio, P.; Koskinen, T.; Barton, E. J.; Piskunov, N.; Maurin, A. S.; Leto, G.; Boisse, I.; Claret, A.; Massi, F.; Kervella, P.; Börne, P.; Heiter, U.; Hargrave, P.; Fletcher, L.; Sánchez Béjar, V. J.; Bézard, B.; Cabral, A.; Michaut, C.; Winter, B.; Sousa, S.; Giuranna, M.; Batista, V.; Frith, J.; Ballerini, P.; López Morales, M.; Monteiro, M.; Tingley, B. W.; Lanza, N.; Maggio, A.; Lundgaard Rasmussen, I.; Altieri, F.; Covino, E.; Coustenis, A.; Heredero, R. L.; Watson, D.; Coudé du Foresto, V.; Liu, S. J.; Sicardy, B.; Deeg, H. J.; Moses, J.; Rodler, F.; Lithgow Bertelloni, C.; Demangeon, O.; Adybekian, V.; Fletcher, L.; Swinyard, B.; Morales Calderón, M.; Fouqué, P.; Deroo, P.; Lo Cicero, Ugo; Hueso, R.; Iro, N.; González Merino, B.; López Puertas, M.; Capria, M. T.; Danielski, C.; Branduardi Raymont, G.; Luntzer, A.; Gaulme, P.; Bulgarelli, A.; Parmentier, V.; Gerard, J. C.; Alard, C.; Frith, J.; Dobrijévic, M.; Medvedev, A.; Barrado, D.; Jacquemoud, S.; Sethenadh, J.; Readorn, K.; Polichtchouk, I.; Petrov, R.; García Piquer, A.; Tabernero, H. M.; White, G.; Pancrazzi, M.; García López, Ramón; Filacchione, G.; Gómez Leal, I.; Rengel, M.; Gesa, L.; Tanga, P.; Mueller Wodarg, I.; Israelian, G.; Rebolo López, R.; Shore, S.; Peralta, J.; Collura, A.; Giro, E.; Del Val Borro, M.; Griffith, C.; Tecsa, M.; Haigh, J.; Moro Martín, A.; Jones, H.; Gizon, L.; Pezzuto, S.; Giani, E.; Mall, U.; Eales, S.; Graczyk, R.; Ramos Zapata, G.; Krupp, N.; Sánchez Lavega, A.; Fossey, S.; Alonso Floriano, F. J.; Justtanot, K.; Santos, N.; Pérez Hoyos, S.; Savini, G.; Chamberlain, S.; Bowles, N.; Kerschbaum, F.; Tozzi, A.; Turrini, D.; Kipping, D.; Maruquette, J. B.; Correira, A.; Trifoglio, M.; Agúndez, Marcelino; Scandaratio, G.; Snellen, I. A.; Scuderi, S.; Femenía Castella, B.; Prisinzano, L.; Oliva, E.; Hébrard, E.; Lodieu, N.; Forget, F.; Chadney, J.; Showman, A.; Gustin, J.; Vinatier, S.; Charnoz, S.; Affer, L.; Rank Lüftinger, T.; Poretti, E.; Lahav, O.; North, C.; Gerard, J. C.; Murgas Alcaino, F.; Yurchenko, S. N.; Widemann, T.; Ward Thompson, D.; Montañés Rodríguez, P.; Kovács, G.; Valdivieso, M. L.; Moya Bedon, A.; Montalto, M.; Christian Jessen, N.; Venot, O.; Koskinen, T.; Lagage, P. O.; Bellucci, G.; Prinja, R.; Pinfield, D.; Banaszkiewicz, M.; Waldmann, I.; Jones, G.; Morello, G.; Crook, J.; Lim, T.; Parviainen, H.; Pallé, E.; Ramos, A. A.; Sanromá, E.; Waters, R.; Morais, H.; Stiepen, A.; Lellouch, E.; Orton, G.; Rezac, L.; Beaulieu, J. P.; Focardi, M.; Mauskopf, P.; Barlow, M.; Guedel, M.; Waltham, D.; Agnor, C.; Encrenaz, T.; Cerulli, R.; Balado, A.; Bouy, H.; Rebordao, J.; Stolarski, M.; Álvarez Iglesias, C. A.; Adriani, A.; Rocchetto, M.; Norgaard Nielsen, H. U.; Hollis, M.; Selig, A.; Malaguti, G.; Burston, R.; Peña Ramírez, K. Y.; Schmider, F. X.; Baffa, C.; Heyrovsky, D.; Figueira, P.; Piccioni, G.; Ottensamer, R.; Radioti, A.; Yelle, R.; Pantin, E.; Miles Paez, P.; Belmonte Avilés, J. A.; Montes, D.; Varley, R.; Viti, S.; Abe, L.; Pinsard, F.; Tessenyi, M.; Di Giorgio, A.; Turrini, D.; Terenzi, L.; Hubert, B.; Griffin, M.; Barber, R. J.; Cole, R.; Gianotti, F.; Blecka, M.; Wawrzaszk, A.; Middleton, K.; De Kok, R.; Martín Torres, Javier; Kehoe, T.; Cho, J.; Machado, P.; Berry, D.; Wisniowski, T.; Grodent, D.; Rataj, M.; Hornstrup, A.; Kerschbaum, F.; Vandenbussche, B.; Stixrude, L.; González Hernández, Carmen; Rebordao, J. [0000-0002-7418-0345]; Kerschbaum, F. [0000-0001-6320-0980]; Abreu, M. [0000-0002-0716-9568]; Tabernero, H. [0000-0002-8087-4298]; López Puertas, M. [0000-0003-2941-7734]; Jacquemoud, S. [0000-0002-1500-5256]; Tennyson, J. [0000-0002-4994-5238]; Focardi, M. [0000-0002-3806-4283]; Leto, G. [0000-0002-0040-5011]; Lodieu, N. [0000-0002-3612-8968]; Tinetti, G. [0000-0001-6058-6654]; Bulgarelli, A. [0000-0001-6347-0649]; Morales Calderon, M. [0000-0001-9526-9499]; Ward Thompson, D. [0000-0003-1140-2761]; Rebolo, R. [0000-0003-3767-7085]; López Valverde, M. A. [0000-0002-7989-4267]; Gillon, M. [0000-0003-1462-7739]; Morgante, G. [0000-0001-9234-7412]; Pena Ramírez, K. [0000-0002-5855-401X]; Galand, M. [0000-0001-5797-914X]; Pancrazzi, M. [0000-0002-3789-2482]; Pilat Lohinger, E. [0000-0002-5292-1923]; Altieri, F. [0000-0002-6338-8300]; Malaguti, G. [0000-0001-9872-3378]; Sánchez Lavega, A. [0000-0001-7234-7634]; Waldmann, I. [0000-0002-4205-5267]; Kovacs, G. [0000-0002-2365-2330]; Guillot, T. [0000-0002-7188-8428]; Monteiro, M. [0000-0001-5644-0898]; Bellucci, G. [0000-0003-0867-8679]; Baffa, C. [0000-0002-4935-100X]; Olivia, E. [0000-0002-9123-0412]; Tizzi, A. [0000-0002-6725-3825]; Selsis, F. [0000-0001-9619-5356]; Scuderi, Salvatore [0000-0002-8637-2109]; Hersant, F. [0000-0002-2687-7500]; Gear, W. [0000-0001-6789-6196]; Damasso, M. [0000-0001-9984-4278]; Irwin, P. [0000-0002-6772-384X]; Pinfield, D. [0000-0002-7804-4260]; Kipping, D. [0000-0002-4365-7366]; Maldonado, J. [0000-0002-4282-1072]; Pace, E. [0000-0001-5870-1772]; Burleigh, M. [0000-0003-0684-7803]; Chadney, J. [0000-0002-5174-2114]; Moro Martín, A. [0000-0001-9504-8426]; Claret, A. [0000-0002-4045-8134]; Rodríguez, P. [0000-0002-6855-9682]; Bezard, B. [0000-0002-5433-5661]; Gómez, H. [0000-0003-3398-0052]; Maldonado, J. [0000-0002-2218-5689]; Michaut, C. [0000-0002-2578-0117]; Hornstrup, A. [0000-0002-3363-0936]; Scholz, A. [0000-0001-8993-5053]; Sánchez Bejar, V. [0000-0002-5086-4232]; López Heredero, R. [0000-0002-2197-8388]; Sanz Forcada, J. [0000-0002-1600-7835]; Danielski, C. [0000-0002-3729-2663]; Vandenbussche, B. [0000-0002-1368-3109]; Sousa, S. [0000-0001-9047-2965]; Medved, A. [0000-0003-2713-8977]; Tinetti, G. [0000-0001-6058-6654]; Bakos, G. [0000-0001-7204-6727]; Ade, P. [0000-0002-5127-0401]; Amado, P. J. [0000-0002-8388-6040]; Martín Torres, J. [0000-0001-6479-2236]; Correira, A. [0000-0002-8946-8579]; Haigh, J. [0000-0001-5504-4754]; Scandariato, G. [0000-0003-2029-0626]; Guedel, M. [0000-0001-9818-0588]; Piskunov, N. [0000-0001-5742-7767]; Adibekyan, V. [0000-0002-0601-6199]; Pérez Hoyos, S. [0000-0001-9797-4917]; Poretti, E. [0000-0003-1200-0473]; Maggio, A. [0000-0001-5154-6108]; Kervella, P. [0000-0003-0626-1749]; Pascale, E. [0000-0002-3242-8154]; Claudi, R. [0000-0001-7707-5105]; Filacchione, G. [0000-0001-9567-0055]; Rickman, H. [0000-0002-9603-6619]; Sanroma, E. [0000-0001-8859-7937]; Agundez, M. [0000-0003-3248-3564]; Montes, D. [0000-0002-7779-238X]; Fletcher, L. [0000-0001-5834-9588]; Rataj, M. [0000-0002-2978-9629]; Stixrude, L. [0000-0003-3778-2432]; Montes, D. [0000-0002-7779-238X]; Morais, M. H. [0000-0001-5333-2736]; Hueso, R. [0000-0003-0169-123X]; Yurchenko, S. [0000-0001-9286-9501]; Morales, J. C. [0000-0003-0061-518X]; Pérez Hoyos, S. [0000-0002-2587-4682]; Santos, N. [0000-0003-4422-2919]; Peralta, J. [0000-0002-6823-1695]; Budaj, J. [0000-0002-9125-7340]; Barlow, M. [0000-0002-3875-1171]; Deeg, H. [0000-0003-0047-4241]; Grassi, D. [0000-0003-1653-3066]; Piccioni, G. [0000-0002-7893-6808]; Barton, E. [0000-0001-5945-9244]; Abreu, M. [0000-0002-0716-9568]; Ribas, I. [0000-0002-6689-0312]; Coates, A. [0000-0002-6185-3125]; García Ramón, J. [0000-0002-8204-6832]; Bouy, H. [0000-0002-7084-487X[; Lognonne, P. [0000-0002-1014-920X]; Demangeon, O. [0000-0001-7918-0355]; Ray, T. [0000-0002-2110-1068]; Guio, P. [0000-0002-1607-5862]; Tanga, P. [0000-0002-2718-997X]; Delgado, M. E. [0000-0003-4434-2195]; Leto, G. [0000-0002-0040-5011]; Prisinzano, L. [0000-0002-8893-2210]; Barstow, J. [0000-0003-3726-5419]; Balado, A. [0000-0003-4268-2516]; Lithgow Bertelloni, C. [0000-0003-0924-6587]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Affer, L. [0000-0001-5600-3778]; Ciaravella, A. [0000-0002-3127-8078]; Barrado Navascues, D. [0000-0002-5971-9242]; Figueira, P. [0000-0001-8504-283X]; Covino, E. [0000-0002-6187-6685]; Venot, O. [0000-0003-2854-765X]; Cabral, A. [0000-0002-9433-871X]; Watson, D. [0000-0002-4465-8264]; Turrini, D. [0000-0002-1923-7740]
The discovery of almost two thousand exoplanets has revealed an unexpectedly diverse planet population. We see gas giants in few-day orbits, whole multi-planet systems within the orbit of Mercury, and new populations of planets with masses between that of the Earth and Neptune—all unknown in the Solar System. Observations to date have shown that our Solar System is certainly not representative of the general population of planets in our Milky Way. The key science questions that urgently need addressing are therefore: What are exoplanets made of? Why are planets as they are? How do planetary systems work and what causes the exceptional diversity observed as compared to the Solar System? The EChO (Exoplanet Characterisation Observatory) space mission was conceived to take up the challenge to explain this diversity in terms of formation, evolution, internal structure and planet and atmospheric composition. This requires in-depth spectroscopic knowledge of the atmospheres of a large and well-defined planet sample for which precise physical, chemical and dynamical information can be obtained. In order to fulfil this ambitious scientific program, EChO was designed as a dedicated survey mission for transit and eclipse spectroscopy capable of observing a large, diverse and well-defined planet sample within its 4-year mission lifetime. The transit and eclipse spectroscopy method, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allows us to measure atmospheric signals from the planet at levels of at least 10−4 relative to the star. This can only be achieved in conjunction with a carefully designed stable payload and satellite platform. It is also necessary to provide broad instantaneous wavelength coverage to detect as many molecular species as possible, to probe the thermal structure of the planetary atmospheres and to correct for the contaminating effects of the stellar photosphere. This requires wavelength coverage of at least 0.55 to 11 μm with a goal of covering from 0.4 to 16 μm. Only modest spectral resolving power is needed, with R ~ 300 for wavelengths less than 5 μm and R ~ 30 for wavelengths greater than this. The transit spectroscopy technique means that no spatial resolution is required. A telescope collecting area of about 1 m2 is sufficiently large to achieve the necessary spectro-photometric precision: for the Phase A study a 1.13 m2 telescope, diffraction limited at 3 μm has been adopted. Placing the satellite at L2 provides a cold and stable thermal environment as well as a large field of regard to allow efficient time-critical observation of targets randomly distributed over the sky. EChO has been conceived to achieve a single goal: exoplanet spectroscopy. The spectral coverage and signal-to-noise to be achieved by EChO, thanks to its high stability and dedicated design, would be a game changer by allowing atmospheric composition to be measured with unparalleled exactness: at least a factor 10 more precise and a factor 10 to 1000 more accurate than current observations. This would enable the detection of molecular abundances three orders of magnitude lower than currently possible and a fourfold increase from the handful of molecules detected to date. Combining these data with estimates of planetary bulk compositions from accurate measurements of their radii and masses would allow degeneracies associated with planetary interior modelling to be broken, giving unique insight into the interior structure and elemental abundances of these alien worlds. EChO would allow scientists to study exoplanets both as a population and as individuals. The mission can target super-Earths, Neptune-like, and Jupiter-like planets, in the very hot to temperate zones (planet temperatures of 300–3000 K) of F to M-type host stars. The EChO core science would be delivered by a three-tier survey. The EChO Chemical Census: This is a broad survey of a few-hundred exoplanets, which allows us to explore the spectroscopic and chemical diversity of the exoplanet population as a whole. The EChO Origin: This is a deep survey of a subsample of tens of exoplanets for which significantly higher signal to noise and spectral resolution spectra can be obtained to explain the origin of the exoplanet diversity (such as formation mechanisms, chemical processes, atmospheric escape). The EChO Rosetta Stones: This is an ultra-high accuracy survey targeting a subsample of select exoplanets. These will be the bright “benchmark” cases for which a large number of measurements would be taken to explore temporal variations, and to obtain two and three dimensional spatial information on the atmospheric conditions through eclipse-mapping techniques. If EChO were launched today, the exoplanets currently observed are sufficient to provide a large and diverse sample. The Chemical Census survey would consist of > 160 exoplanets with a range of planetary sizes, temperatures, orbital parameters and stellar host properties. Additionally, over the next 10 years, several new ground- and space-based transit photometric surveys and missions will come on-line (e.g. NGTS, CHEOPS, TESS, PLATO), which will specifically focus on finding bright, nearby systems. The current rapid rate of discovery would allow the target list to be further optimised in the years prior to EChO’s launch and enable the atmospheric characterisation of hundreds of planets.