PLATO as it is: a legacy mission for Galactic archaeology

A. Miglio , C. Chiappini , B. Mosser (1) , G. R. Davies , K. Freeman (2) , L. Girardi , P. Jofre , D. Kawata , B. M. Rendle , M. Valentini (3) , L. Casagrande , W. J. Chaplin (4, 5) , G. Gilmore , K. Hawkins , B. Holl , T. Appourchaux , K. Belkacem (1) , D. Bossini , K. Brogaard (6) , M. -J. Goupil , J. Montalban , A. Noels , F. Anders , T. Rodrigues (7) , G. Piotto , D. Pollacco , H. Rauer (8) , C. Allende Prieto , P. P. Avelino , C. Babusiaux , C. Barban , B. Barbuy , S. Basu (9) , Frédéric Baudin (10) , O. Benomar , O. Bienayme , J. Binney , J. Bland-Hawthorn , A. Bressan , C. Cacciari (11) , T. L. Campante , S. Cassisi , J. Christensen-Dalsgaard (12) , F. Combes (13) , O. Creevey (14) , M. S. Cunha (15) , R. S. de Jong , P. de Laverny (16) , S. Degl'Innocenti , S. Deheuvels (17) , E. Depagne (18) , J. Deridder , P. Dimatteo , M. P. Di Mauro , M. -A. Dupret , P. Eggenberger (19) , Y. Elsworth , B. Famaey (20) , S. Feltzing , R. A. Garcia (21) , O. Gerhard (22) , B. K. Gibson , Laurent Gizon (23) , M. Haywood (24) , R. Handberg (4) , U. Heiter , S. Hekker , D. Huber (25, 4) , R. Ibata , D. Katz (26) , S. D. Kawaler , H. Kjeldsen (12) , D. W. Kurtz (27) , N. Lagarde (28) , Y. Lebreton (29, 1) , M. N. Lund , S. R. Majewski , P. Marigo , M. Martig , S. Mathur (30) , I. Minchev (3) , T. Morel , S. Ortolani , M. H. Pinsonneault , B. Plez (31) , P. G. Prada Moroni , D. Pricopi , A. Recio-Blanco (16) , C. Reylé (28) , A. Robin (28) , I. W. Roxburgh , M. Salaris (32) , B. X. Santiago , R. Schiavon , A. Serenelli (33) , S. Sharma (34) , V. Silva Aguirre (4) , C. Soubiran , M. Steinmetz (3) , D. Stello (4) , K. G. Strassmeier (35) , P. Ventura , R. Ventura , N. A. Walton , C. C. Worley

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
2 ASU - Arizona State University [Tempe]
3 AIP - Leibniz-Institut für Astrophysik Potsdam
4 Department of Physics and Astronomy [Aarhus]
5 School of Physics and Astronomy [Birmingham]
6 SAC - Stellar Astrophysics Centre [Aarhus]
7 OAPD - INAF - Osservatorio Astronomico di Padova
8 DLR Institut für Planetenforschung
9 Department of Astronomy [New Haven]
10 IAS - Institut d'astrophysique spatiale
11 OABO - INAF - Osservatorio Astronomico di Bologna
12 DASC - Danish AsteroSeismology Centre
13 LERMA - LERMA Cergy
14 IAS - Institut d'astrophysique spatiale
15 Universidade de Aveiro
16 LAGRANGE - Joseph Louis LAGRANGE
17 IRAP - Institut de recherche en astrophysique et planétologie
18 SAAO - South African Astronomical Observatory
19 UNIGE - Université de Genève = University of Geneva
20 ObAS - Observatoire astronomique de Strasbourg
21 UdG - Universitat de Girona
22 MPE - Max-Planck-Institut für Extraterrestrische Physik
23 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research
24 GEPI - Galaxies, Etoiles, Physique, Instrumentation
25 SETI Institute
26 UIUC - University of Illinois at Urbana-Champaign [Urbana]
27 UFSC - Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis]
28 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)
29 IPR - Institut de Physique de Rennes
30 SSI - Space Science Institute [Boulder]
31 LUPM - Laboratoire Univers et Particules de Montpellier
32 Astrophysical Research Institute [Liverpool]
33 ICE-CSIC - Institute of Space Sciences [Barcelona]
34 SIfA - Sydney Institute for Astronomy
35 AIP - Leibniz Institute for Astrophysics Potsdam

Deciphering the assembly history of the Milky Way is a formidable task, which becomes possible only if one can produce high-resolution chrono-chemo-kinematical maps of the Galaxy. Data from large-scale astrometric and spectroscopic surveys will soon provide us with a well-defined view of the current chemo-kinematical structure of the Milky Way, but will only enable a blurred view on the temporal sequence that led to the present-day Galaxy. As demonstrated by the (ongoing) exploitation of data from the pioneering photometric missions CoRoT, Kepler, and K2, asteroseismology provides the way forward: solar-like oscillating giants are excellent evolutionary clocks thanks to the availability of seismic constraints on their mass and to the tight age-initial-mass relation they adhere to. In this paper we identify five key outstanding questions relating to the formation and evolution of the Milky Way that will need precise and accurate ages for large samples of stars to be addressed, and we identify the requirements in terms of number of targets and the precision on the stellar properties that are needed to tackle such questions. By quantifying the asteroseismic yields expected from PLATO for red-giant stars, we demonstrate that these requirements are within the capabilities of the current instrument design, provided that observations are sufficiently long to identify the evolutionary state and allow robust and precise determination of acoustic-mode frequencies. This will allow us to harvest data of sufficient quality to reach a 10% precision in age. This is a fundamental pre-requisite to then reach the more ambitious goal of a similar level of accuracy, which will only be possible if we have to hand a careful appraisal of systematic uncertainties on age deriving from our limited understanding of stellar physics, a goal which conveniently falls within the main aims of PLATO's core science.

Mots clés: Astrophysics - Astrophysics of Galaxies; Astrophysics - Solar and Stellar Astrophysics

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]

A. Miglio, C. Chiappini, B. Mosser, G. R. Davies, K. Freeman, et al.. PLATO as it is: a legacy mission for Galactic archaeology. Astronomical Notes / Astronomische Nachrichten, 2017, 338 (6), pp.644-661. ⟨10.1002/asna.201713385⟩. ⟨hal-01541393⟩