Bibcode
Tinetti, G.; Beaulieu, J. P.; Henning, T.; Meyer, M.; Micela, G.; Ribas, I.; Stam, D.; Swain, M.; Krause, O.; Ollivier, M.; Pace, E.; Swinyard, B.; Aylward, A.; van Boekel, R.; Coradini, A.; Encrenaz, T.; Snellen, I.; Zapatero-Osorio, M. R.; Bouwman, J.; Cho, J. Y.-K.; Coudé de Foresto, V.; Guillot, T.; Lopez-Morales, M.; Mueller-Wodarg, I.; Pallé, E.; Selsis, F.; Sozzetti, A.; Ade, P. A. R.; Achilleos, N.; Adriani, A.; Agnor, C. B.; Afonso, C.; Allende-Prieto, C.; Bakos, G.; Barber, R. J.; Barlow, M.; Batista, V.; Bernath, P.; Bézard, B.; Bordé, P.; Brown, L. R.; Cassan, A.; Cavarroc, C.; Ciaravella, A.; Cockell, C.; Coustenis, A.; Danielski, C.; Decin, L.; Kok, R. De; Demangeon, O.; Deroo, P.; Doel, P.; Drossart, P.; Fletcher, L. N.; Focardi, M.; Forget, F.; Fossey, S.; Fouqué, P.; Frith, J.; Galand, M.; Gaulme, P.; González-Hernández, J. I. ; Grasset, O.; Grassi, D.; Grenfell, J. L.; Griffin, M. J.; Griffith, C. A.; Grözinger, U.; Guedel, M.; Guio, P.; Hainaut, O.; Hargreaves, R.; Hauschildt, P. H.; Heng, K.; Heyrovsky, D.; Hueso, R.; Irwin, P.; Kaltenegger, L.; Kervella, P.; Kipping, D.; Koskinen, T. T.; Kovács, G.; La Barbera, A.; Lammer, H.; Lellouch, E.; Leto, G.; Lopez Morales, M.; Lopez Valverde, M. A.; Lopez-Puertas, M.; Lovis, C.; Maggio, A.; Maillard, J. P.; Maldonado Prado, J.; Marquette, J. B.; Martin-Torres, F. J.; Maxted, P.; Miller, S.; Molinari, S.; Montes, D.; Moro-Martin, A. et al.
Referencia bibliográfica
Experimental Astronomy, October 2012, Volume 34, 311, pp.43
Fecha de publicación:
10
2012
Revista
Número de citas
107
Número de citas referidas
86
Descripción
A dedicated mission to investigate exoplanetary atmospheres represents a
major milestone in our quest to understand our place in the universe by
placing our Solar System in context and by addressing the suitability of
planets for the presence of life. EChO—the Exoplanet
Characterisation Observatory—is a mission concept specifically
geared for this purpose. EChO will provide simultaneous,
multi-wavelength spectroscopic observations on a stable platform that
will allow very long exposures. The use of passive cooling, few moving
parts and well established technology gives a low-risk and potentially
long-lived mission. EChO will build on observations by Hubble, Spitzer
and ground-based telescopes, which discovered the first molecules and
atoms in exoplanetary atmospheres. However, EChO's configuration and
specifications are designed to study a number of systems in a consistent
manner that will eliminate the ambiguities affecting prior observations.
EChO will simultaneously observe a broad enough spectral
region—from the visible to the mid-infrared—to constrain
from one single spectrum the temperature structure of the atmosphere,
the abundances of the major carbon and oxygen bearing species, the
expected photochemically-produced species and magnetospheric signatures.
The spectral range and resolution are tailored to separate bands
belonging to up to 30 molecules and retrieve the composition and
temperature structure of planetary atmospheres. The target list for EChO
includes planets ranging from Jupiter-sized with equilibrium
temperatures T eq up to 2,000 K, to those of a few Earth
masses, with T eq u223c 300 K. The list will include planets
with no Solar System analog, such as the recently discovered planets
GJ1214b, whose density lies between that of terrestrial and gaseous
planets, or the rocky-iron planet 55 Cnc e, with day-side temperature
close to 3,000 K. As the number of detected exoplanets is growing
rapidly each year, and the mass and radius of those detected steadily
decreases, the target list will be constantly adjusted to include the
most interesting systems. We have baselined a dispersive spectrograph
design covering continuously the 0.4-16 μm spectral range in 6
channels (1 in the visible, 5 in the InfraRed), which allows the
spectral resolution to be adapted from several tens to several hundreds,
depending on the target brightness. The instrument will be mounted
behind a 1.5 m class telescope, passively cooled to 50 K, with the
instrument structure and optics passively cooled to u223c45 K. EChO will
be placed in a grand halo orbit around L2. This orbit, in combination
with an optimised thermal shield design, provides a highly stable
thermal environment and a high degree of visibility of the sky to
observe repeatedly several tens of targets over the year. Both the
baseline and alternative designs have been evaluated and no critical
items with Technology Readiness Level (TRL) less than 4-5 have been
identified. We have also undertaken a first-order cost and development
plan analysis and find that EChO is easily compatible with the ESA
M-class mission framework.