Abstract
Original language | English |
---|---|
Pages (from-to) | 329-391 |
Number of pages | 63 |
Journal | Experimental astronomy (Print) |
Volume | 40 |
Issue number | 2-3 |
Early online date | 29 Nov 2015 |
DOIs | |
Publication status | Published - 2015 |
Keywords
- Atmospheric science
- Exoplanets
- IR astronomy
- Space missions
- Spectroscopy
- Aerospace Engineering
- Rymd- och flygteknik
Access to Document
- 10.1007/s10686-015-9484-8Licence: CC BY
- Tinetti-et-al-echo-science-exp-astron-vor
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Final published version, 8.22 MBLicence: CC BY
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The EChO science case. / Tinetti, Giovanna; Drossart, Pierre; Eccleston, Paul; Hartogh, Paul; Isaak, Kate; Linder, Martin; Lovis, Christophe; Micela, Giusi; Ollivier, Marc; Puig, Ludovic; Ribas, Ignasi; Snellen, Ignas; Swinyard, Bruce; Allard, France; Barstow, Joanna; Cho, James; Coustenis, Athena; Cockell, Charles; Correia, Alexandre; Decin, Leen; de Kok, Remco; Deroo, Pieter; Encrenaz, Therese; Forget, Francois; Glasse, Alistair; Griffith, Caitlin; Guillot, Tristan; Koskinen, T.; Lammer, Helmut; Leconte, Jeremy; Maxted, Pierre; Mueller-Wodarg, Ingo; Nelson, Richard; North, Chris; Pallé, Enric; Pagano, Isabella; Piccioni, Guseppe; Pinfield, David; Selsis, Franck; Sozzetti, Alessandro; Stixrude, Lars; Tennyson, Jonathan; Turrini, Diego; Zapatero-Osorio, Mariarosa; Beaulieu, Jean-Philippe; Grodent, Denis; Guedel, Manuel; Luz, David; Nørgaard-Nielsen, Hans Ulrik; Ray, Tom; Rickman, Hans; Selig, Avri; Swain, Mark; Banaszkiewicz, Marek; Barlow, Mike; Bowles, Neil; Branduardi-Raymont, Graziella; du Foresto, Vincent Coudé; Gerard, Jean-Claude; Gizon, Laurent; Hornstrup, Allan; Jarchow, Christopher; Kerschbaum, Franz; Kovacs, Géza; Lagage, Pierre-Olivier; Lim, Tanya; Lopez-Morales, Mercedes; Malaguti, Giuseppe; Pace, Emanuele; Pascale, Enzo; Vandenbussche, Bart; Wright, Gillian; Ramos Zapata, Gonzalo; Adriani, Alberto; Azzollini, Ruymán; Balado, Ana; Bryson, Ian; Burston, Raymond; Colomé, Josep; Crook, Martin; Di Giorgio, Anna; Griffin, Matt; Hoogeveen, Ruud; Ottensamer, Roland; Irshad, Ranah; Middleton, Kevin; Morgante, Gianluca; Pinsard, Frederic; Rataj, Mirek; Reess, Jean-Michel; Savini, Giorgio; Schrader, Jan-Rutger; Stamper, Richard; Winter, Berend; Abe, L.; Abreu, M.; Achilleos, N.; Ade, P.; Adybekian, V.; Affer, L.; Agnor, C.; Agundez, M.; Alard, C.; Alcala, J.; Allende Prieto, C.; Alonso Floriano, F. J.; Altieri, F.; Alvarez Iglesias, C. A.; Amado, P.; Andersen, A.; Aylward, A.; Baffa, C.; Bakos, G.; Ballerini, P.; Banaszkiewicz, M.; Barber, R. J.; Barrado, D.; Barton, E. J.; Batista, V.; Bellucci, G.; Belmonte Avilés, J. A.; Berry, D.; Bézard, B.; Biondi, D.; Błęcka, M.; Boisse, I.; Bonfond, B.; Bordé, P.; Börner, P.; Bouy, H.; Brown, L.; Buchhave, L.; Budaj, J.; Bulgarelli, A.; Burleigh, M.; Cabral, A.; Capria, M. T.; Cassan, A.; Cavarroc, C.; Cecchi-Pestellini, C.; Cerulli, R.; Chadney, J.; Chamberlain, S.; Charnoz, S.; Christian Jessen, N.; Ciaravella, A.; Claret, A.; Claudi, R.; Coates, A.; Cole, R.; Collura, A.; Cordier, D.; Covino, E.; Danielski, C.; Damasso, M.; Deeg, H. J.; Delgado-Mena, E.; Del Vecchio, C.; Demangeon, O.; De Sio, A.; De Wit, J.; Dobrijévic, M.; Doel, P.; Dominic, C.; Dorfi, E.; Eales, S.; Eiroa, C.; Espinoza Contreras, M.; Esposito, M.; Eymet, V.; Fabrizio, N.; Fernández, M.; Femenía Castella, B.; Figueira, P.; Filacchione, G.; Fletcher, L.; Focardi, M.; Fossey, S.; Fouqué, P.; Frith, J.; Galand, M.; Gambicorti, L.; Gaulme, P.; García López, R. J.; Garcia-Piquer, A.; Gear, W.; Gerard, J. -C.; Gesa, L.; Giani, E.; Gianotti, F.; Gillon, M.; Giro, E.; Giuranna, M.; Gomez, H.; Gomez-Leal, I.; Gonzalez Hernandez, J.; González Merino, B.; Graczyk, R.; Grassi, D.; Guardia, J.; Guio, P.; Gustin, J.; Hargrave, P.; Haigh, J.; Hébrard, E.; Heiter, U.; Heredero, R. L.; Herrero, E.; Hersant, F.; Heyrovsky, D.; Hollis, M.; Hubert, B.; Hueso, R.; Israelian, G.; Iro, N.; Irwin, P.; Jacquemoud, S.; Jones, G.; Jones, H.; Justtanont, K.; Kehoe, T.; Kerschbaum, F.; Kerins, E.; Kervella, P.; Kipping, D.; Koskinen, T.; Krupp, N.; Lahav, O.; Laken, B.; Lanza, N.; Lellouch, E.; Leto, G.; Licandro Goldaracena, J.; Lithgow-Bertelloni, C.; Liu, S. J.; Lo Cicero, U.; Lodieu, N.; Lognonné, P.; Lopez-Puertas, M.; Lopez-Valverde, M. A.; Lundgaard Rasmussen, I.; Luntzer, A.; Machado, P.; MacTavish, C.; Maggio, A.; Maillard, J. -P.; Magnes, W.; Maldonado, J.; Mall, U.; Marquette, J. -B.; Mauskopf, P.; Massi, F.; Maurin, A. -S.; Medvedev, A.; Michaut, C.; Miles-Paez, P.; Montalto, M.; Montañés Rodríguez, P.; Monteiro, M.; Montes, D ; Morais, H.; Morales, J. C.; Morales-Calderón, M.; Morello, G.; Moro Martín, A.; Moses, J.; Moya Bedon, A.; Murgas Alcaino, F.; Oliva, E.; Orton, G.; Palla, F.; Pancrazzi, M.; Pantin, E.; Parmentier, V.; Parviainen, H.; Peña Ramírez, K. Y.; Peralta, J.; Perez-Hoyos, S.; Petrov, R.; Pezzuto, S.; Pietrzak, R.; Pilat-Lohinger, E.; Piskunov, N.; Prinja, R.; Prisinzano, L.; Polichtchouk, I.; Poretti, E.; Radioti, A.; Ramos, A. A.; Rank-Lüftinger, T.; Read, P.; Readorn, K.; Rebolo López, R.; Rebordão, J.; Rengel, M.; Rezac, L.; Rocchetto, M.; Rodler, F.; Sánchez Béjar, V. J.; Sanchez Lavega, A.; Sanromá, E.; Santos, N.; Sanz Forcada, J.; Scandariato, G.; Schmider, F. -X.; Scholz, A.; Scuderi, S.; Sethenadh, J.; Shore, S.; Showman, A.; Sicardy, B.; Sitek, P.; Smith, A.; Soret, L.; Sousa, S.; Stiepen, A.; Stolarski, M.; Strazzulla, G.; Tabernero, H. M.; Tanga, P.; Tecsa, M.; Temple, J.; Terenzi, L.; Tessenyi, M.; Testi, L.; Thompson, S.; Thrastarson, H.; Tingley, B. W.; Trifoglio, M.; Martín Torres, J.; Tozzi, A.; Turrini, D.; Varley, R.; Vakili, F.; de Val-Borro, M.; Valdivieso, M. L.; Venot, O.; Villaver, E.; Vinatier, S.; Viti, S.; Waldmann, I.; Waltham, D.; Ward-Thompson, D.; Waters, R.; Watkins, C.; Watson, D.; Wawer, P.; Wawrzaszk, A.; White, G.; Widemann, T.; Winek, W.; Wiśniowski, T.; Yelle, R.; Yung, Y.; Yurchenko, S. N.
In: Experimental astronomy (Print), Vol. 40, No. 2-3, 2015, p. 329-391.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - The EChO science case
AU - Tinetti, Giovanna
AU - Drossart, Pierre
AU - Eccleston, Paul
AU - Hartogh, Paul
AU - Isaak, Kate
AU - Linder, Martin
AU - Lovis, Christophe
AU - Micela, Giusi
AU - Ollivier, Marc
AU - Puig, Ludovic
AU - Ribas, Ignasi
AU - Snellen, Ignas
AU - Swinyard, Bruce
AU - Allard, France
AU - Barstow, Joanna
AU - Cho, James
AU - Coustenis, Athena
AU - Cockell, Charles
AU - Correia, Alexandre
AU - Decin, Leen
AU - de Kok, Remco
AU - Deroo, Pieter
AU - Encrenaz, Therese
AU - Forget, Francois
AU - Glasse, Alistair
AU - Griffith, Caitlin
AU - Guillot, Tristan
AU - Koskinen, T.
AU - Lammer, Helmut
AU - Leconte, Jeremy
AU - Maxted, Pierre
AU - Mueller-Wodarg, Ingo
AU - Nelson, Richard
AU - North, Chris
AU - Pallé, Enric
AU - Pagano, Isabella
AU - Piccioni, Guseppe
AU - Pinfield, David
AU - Selsis, Franck
AU - Sozzetti, Alessandro
AU - Stixrude, Lars
AU - Tennyson, Jonathan
AU - Turrini, Diego
AU - Zapatero-Osorio, Mariarosa
AU - Beaulieu, Jean-Philippe
AU - Grodent, Denis
AU - Guedel, Manuel
AU - Luz, David
AU - Nørgaard-Nielsen, Hans Ulrik
AU - Ray, Tom
AU - Rickman, Hans
AU - Selig, Avri
AU - Swain, Mark
AU - Banaszkiewicz, Marek
AU - Barlow, Mike
AU - Bowles, Neil
AU - Branduardi-Raymont, Graziella
AU - du Foresto, Vincent Coudé
AU - Gerard, Jean-Claude
AU - Gizon, Laurent
AU - Hornstrup, Allan
AU - Jarchow, Christopher
AU - Kerschbaum, Franz
AU - Kovacs, Géza
AU - Lagage, Pierre-Olivier
AU - Lim, Tanya
AU - Lopez-Morales, Mercedes
AU - Malaguti, Giuseppe
AU - Pace, Emanuele
AU - Pascale, Enzo
AU - Vandenbussche, Bart
AU - Wright, Gillian
AU - Ramos Zapata, Gonzalo
AU - Adriani, Alberto
AU - Azzollini, Ruymán
AU - Balado, Ana
AU - Bryson, Ian
AU - Burston, Raymond
AU - Colomé, Josep
AU - Crook, Martin
AU - Di Giorgio, Anna
AU - Griffin, Matt
AU - Hoogeveen, Ruud
AU - Ottensamer, Roland
AU - Irshad, Ranah
AU - Middleton, Kevin
AU - Morgante, Gianluca
AU - Pinsard, Frederic
AU - Rataj, Mirek
AU - Reess, Jean-Michel
AU - Savini, Giorgio
AU - Schrader, Jan-Rutger
AU - Stamper, Richard
AU - Winter, Berend
AU - Abe, L.
AU - Abreu, M.
AU - Achilleos, N.
AU - Ade, P.
AU - Adybekian, V.
AU - Affer, L.
AU - Agnor, C.
AU - Agundez, M.
AU - Alard, C.
AU - Alcala, J.
AU - Allende Prieto, C.
AU - Alonso Floriano, F. J.
AU - Altieri, F.
AU - Alvarez Iglesias, C. A.
AU - Amado, P.
AU - Andersen, A.
AU - Aylward, A.
AU - Baffa, C.
AU - Bakos, G.
AU - Ballerini, P.
AU - Banaszkiewicz, M.
AU - Barber, R. J.
AU - Barrado, D.
AU - Barton, E. J.
AU - Batista, V.
AU - Bellucci, G.
AU - Belmonte Avilés, J. A.
AU - Berry, D.
AU - Bézard, B.
AU - Biondi, D.
AU - Błęcka, M.
AU - Boisse, I.
AU - Bonfond, B.
AU - Bordé, P.
AU - Börner, P.
AU - Bouy, H.
AU - Brown, L.
AU - Buchhave, L.
AU - Budaj, J.
AU - Bulgarelli, A.
AU - Burleigh, M.
AU - Cabral, A.
AU - Capria, M. T.
AU - Cassan, A.
AU - Cavarroc, C.
AU - Cecchi-Pestellini, C.
AU - Cerulli, R.
AU - Chadney, J.
AU - Chamberlain, S.
AU - Charnoz, S.
AU - Christian Jessen, N.
AU - Ciaravella, A.
AU - Claret, A.
AU - Claudi, R.
AU - Coates, A.
AU - Cole, R.
AU - Collura, A.
AU - Cordier, D.
AU - Covino, E.
AU - Danielski, C.
AU - Damasso, M.
AU - Deeg, H. J.
AU - Delgado-Mena, E.
AU - Del Vecchio, C.
AU - Demangeon, O.
AU - De Sio, A.
AU - De Wit, J.
AU - Dobrijévic, M.
AU - Doel, P.
AU - Dominic, C.
AU - Dorfi, E.
AU - Eales, S.
AU - Eiroa, C.
AU - Espinoza Contreras, M.
AU - Esposito, M.
AU - Eymet, V.
AU - Fabrizio, N.
AU - Fernández, M.
AU - Femenía Castella, B.
AU - Figueira, P.
AU - Filacchione, G.
AU - Fletcher, L.
AU - Focardi, M.
AU - Fossey, S.
AU - Fouqué, P.
AU - Frith, J.
AU - Galand, M.
AU - Gambicorti, L.
AU - Gaulme, P.
AU - García López, R. J.
AU - Garcia-Piquer, A.
AU - Gear, W.
AU - Gerard, J. -C.
AU - Gesa, L.
AU - Giani, E.
AU - Gianotti, F.
AU - Gillon, M.
AU - Giro, E.
AU - Giuranna, M.
AU - Gomez, H.
AU - Gomez-Leal, I.
AU - Gonzalez Hernandez, J.
AU - González Merino, B.
AU - Graczyk, R.
AU - Grassi, D.
AU - Guardia, J.
AU - Guio, P.
AU - Gustin, J.
AU - Hargrave, P.
AU - Haigh, J.
AU - Hébrard, E.
AU - Heiter, U.
AU - Heredero, R. L.
AU - Herrero, E.
AU - Hersant, F.
AU - Heyrovsky, D.
AU - Hollis, M.
AU - Hubert, B.
AU - Hueso, R.
AU - Israelian, G.
AU - Iro, N.
AU - Irwin, P.
AU - Jacquemoud, S.
AU - Jones, G.
AU - Jones, H.
AU - Justtanont, K.
AU - Kehoe, T.
AU - Kerschbaum, F.
AU - Kerins, E.
AU - Kervella, P.
AU - Kipping, D.
AU - Koskinen, T.
AU - Krupp, N.
AU - Lahav, O.
AU - Laken, B.
AU - Lanza, N.
AU - Lellouch, E.
AU - Leto, G.
AU - Licandro Goldaracena, J.
AU - Lithgow-Bertelloni, C.
AU - Liu, S. J.
AU - Lo Cicero, U.
AU - Lodieu, N.
AU - Lognonné, P.
AU - Lopez-Puertas, M.
AU - Lopez-Valverde, M. A.
AU - Lundgaard Rasmussen, I.
AU - Luntzer, A.
AU - Machado, P.
AU - MacTavish, C.
AU - Maggio, A.
AU - Maillard, J. -P.
AU - Magnes, W.
AU - Maldonado, J.
AU - Mall, U.
AU - Marquette, J. -B.
AU - Mauskopf, P.
AU - Massi, F.
AU - Maurin, A. -S.
AU - Medvedev, A.
AU - Michaut, C.
AU - Miles-Paez, P.
AU - Montalto, M.
AU - Montañés Rodríguez, P.
AU - Monteiro, M.
AU - Montes, D
AU - Morais, H.
AU - Morales, J. C.
AU - Morales-Calderón, M.
AU - Morello, G.
AU - Moro Martín, A.
AU - Moses, J.
AU - Moya Bedon, A.
AU - Murgas Alcaino, F.
AU - Oliva, E.
AU - Orton, G.
AU - Palla, F.
AU - Pancrazzi, M.
AU - Pantin, E.
AU - Parmentier, V.
AU - Parviainen, H.
AU - Peña Ramírez, K. Y.
AU - Peralta, J.
AU - Perez-Hoyos, S.
AU - Petrov, R.
AU - Pezzuto, S.
AU - Pietrzak, R.
AU - Pilat-Lohinger, E.
AU - Piskunov, N.
AU - Prinja, R.
AU - Prisinzano, L.
AU - Polichtchouk, I.
AU - Poretti, E.
AU - Radioti, A.
AU - Ramos, A. A.
AU - Rank-Lüftinger, T.
AU - Read, P.
AU - Readorn, K.
AU - Rebolo López, R.
AU - Rebordão, J.
AU - Rengel, M.
AU - Rezac, L.
AU - Rocchetto, M.
AU - Rodler, F.
AU - Sánchez Béjar, V. J.
AU - Sanchez Lavega, A.
AU - Sanromá, E.
AU - Santos, N.
AU - Sanz Forcada, J.
AU - Scandariato, G.
AU - Schmider, F. -X.
AU - Scholz, A.
AU - Scuderi, S.
AU - Sethenadh, J.
AU - Shore, S.
AU - Showman, A.
AU - Sicardy, B.
AU - Sitek, P.
AU - Smith, A.
AU - Soret, L.
AU - Sousa, S.
AU - Stiepen, A.
AU - Stolarski, M.
AU - Strazzulla, G.
AU - Tabernero, H. M.
AU - Tanga, P.
AU - Tecsa, M.
AU - Temple, J.
AU - Terenzi, L.
AU - Tessenyi, M.
AU - Testi, L.
AU - Thompson, S.
AU - Thrastarson, H.
AU - Tingley, B. W.
AU - Trifoglio, M.
AU - Martín Torres, J.
AU - Tozzi, A.
AU - Turrini, D.
AU - Varley, R.
AU - Vakili, F.
AU - de Val-Borro, M.
AU - Valdivieso, M. L.
AU - Venot, O.
AU - Villaver, E.
AU - Vinatier, S.
AU - Viti, S.
AU - Waldmann, I.
AU - Waltham, D.
AU - Ward-Thompson, D.
AU - Waters, R.
AU - Watkins, C.
AU - Watson, D.
AU - Wawer, P.
AU - Wawrzaszk, A.
AU - White, G.
AU - Widemann, T.
AU - Winek, W.
AU - Wiśniowski, T.
AU - Yelle, R.
AU - Yung, Y.
AU - Yurchenko, S. N.
PY - 2015
Y1 - 2015
N2 - 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.
AB - 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.
KW - Atmospheric science
KW - Exoplanets
KW - IR astronomy
KW - Space missions
KW - Spectroscopy
KW - Aerospace Engineering
KW - Rymd- och flygteknik
U2 - 10.1007/s10686-015-9484-8
DO - 10.1007/s10686-015-9484-8
M3 - Article
VL - 40
SP - 329
EP - 391
JO - Experimental astronomy (Print)
JF - Experimental astronomy (Print)
SN - 0922-6435
IS - 2-3
ER -