Exoplanets & Exomoons

Ariel: Enabling Planetary Science Across Light-years

By Keith Cowing
April 12, 2021
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Ariel: Enabling Planetary Science Across Light-years
Schematic representation of our current understanding of the formation and evolutionary paths that, starting from the gas and dust in circumstellar discs (the bottom left corner of the diagram), create the different kinds of planets currently observed. Black and orange arrows indicate the paths linked to the formation process (e.g. disc instability, solid accretion, gas capture) while blue arrows indicate the paths shaped by atmospheric evolution (e.g. atmospheric escape, atmospheric erosion, outgassing). Planets are divided into three broad categories: high-density planets (mainly composed by Si, Mg, Fe, C, O), gas-rich planets (for which H and He represent a significant fraction of their mass) and transitional planets (encompassing the transition between the largest high-density planets and the smallest gas-rich planets). The Solar System offers us examples of high-density planets and gas-rich planets but not of transitional planets, for which we need to look to exoplanets. The light blue histogram shows the frequency rate of planets across the transition region as a function of planetary radii from Fulton & Petigura (2018). Figure updated from Turrini et al. (2018).

Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA’s Cosmic Vision programme to be launched in 2029.

During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System.

The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler.

The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution.

Giovanna Tinetti (UCL), Paul Eccleston (RAL Space), Carole Haswell (OU), Pierre-Olivier Lagage (CEA), Jérémy Leconte (U. de Bordeaux), Theresa Lüftinger (ESA), Giusi Micela (INAF-OAPa), Michel Min (SRON), Göran Pilbratt (ESA), Ludovic Puig (ESA), Mark Swain (JPL), Leonardo Testi (ESO), Diego Turrini (INAF-IAPS), Bart Vandenbussche (KU Leuven), Maria Rosa Zapatero Osorio (INTA), Anna Aret (U. of Tartu), Jean-Philippe Beaulieu (IAP), Lars Buchhave (DTU), Martin Ferus (J. Heyrovský Institute), Matt Griffin (U. of Cardiff), Manuel Guedel (U. of Vienna), Paul Hartogh (MPS), Pedro Machado (IA), Giuseppe Malaguti (INAF-OAS), Enric Pallé (IAC), Mirek Rataj (CBK), Tom Ray (Dublin Institute for Advanced Studies), Ignasi Ribas (IEEC-CSIC), Robert Szabó (Konkoly Obs.), Jonathan Tan (Chalmers U.), Stephanie Werner (U. of Oslo), Francesco Ratti (ESA), Carsten Scharmberg (ESA), Jean-Christophe Salvignol (ESA), Nathalie Boudin (ESA), Jean-Philippe Halain (ESA), Martin Haag (ESA), Pierre-Elie Crouzet (ESA), Ralf Kohley (ESA), Kate Symonds (ESA), Florian Renk (ESA), Andrew Caldwell (RAL Space), Manuel Abreu (IA), Gustavo Alonso (UPM), Jerome Amiaux (CEA), Michel Berthé (CEA), Georgia Bishop (RAL Space), Neil Bowles (U. of Oxford), Manuel Carmona (IEEC-UB), Deirdre Coffey (DIAS), Josep Colomé (IEEC-CSIC), Martin Crook (RAL TD), Lucile Désjonqueres (RAL Space), José J. Díaz (IAC), Rachel Drummond (RAL Space), Mauro Focardi (INAF-OAA), Jose M. Gómez (IEEC), Warren Holmes (JPL), Matthijs Krijger (SRON), Zsolt Kovacs (Admatis), Tom Hunt (MSSL), Richardo Machado (ActiveSpace), Gianluca Morgante (INAF-OAS), Marc Ollivier (IAS), Roland Ottensamer (U. of Vienna), Emanuele Pace (U. di Firenze), Teresa Pagano (RUAG), Enzo Pascale (La Sapienza), Chris Pearson (RAL Space), Søren Møller Pedersen (DTU), Moshe Pniel (JPL), Stéphane Roose (CSL), Giorgio Savini (UCL), Richard Stamper (RAL Space), Peter Szirovicza (Admatis), Janos Szoke (Admatis), Ian Tosh (RAL Space), Francesc Vilardell (IEEC), Joanna Barstow (OU), Luca Borsato (U. of Padova), Sarah Casewell (U. of Leicester), Quentin Changeat (UCL), Benjamin Charnay (LESIA), Svatopluk Civiš (J. Heyrovský Institute), Vincent Coudé du Foresto (LESIA), Athena Coustenis (LESIA), Nicolas Cowan (McGill U.), Camilla Danielski (IAA), Olivier Demangeon (IA), Pierre Drossart (IAP), Billy N. Edwards (UCL), Gabriella Gilli (IA), Therese Encrenaz (LESIA), Csaba Kiss (Konkoly Obs.), Anastasia Kokori (CSED), Masahiro Ikoma (NAOJ), Juan Carlos Morales (IEEC), João Mendonça (DTU), Andrea Moneti (IAP), Lorenzo Mugnai et al. (218 additional authors not shown)

Comments: Ariel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: this https URL
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
Report number: ESA/SCI(2020)1
Cite as: arXiv:2104.04824 [astro-ph.IM] (or arXiv:2104.04824v1 [astro-ph.IM] for this version)
Submission history
From: Giovanna Tinetti
[v1] Sat, 10 Apr 2021 17:42:49 UTC (30,565 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻