stars: interiors; stars: fundamental parameters; asteroseismology; stars: oscillations; planetary systems; Astrophysics - Solar and Stellar Astrophysics
Abstract :
[en] Context. The CoRoT and Kepler missions have paved the way for synergies between exoplanetology and asteroseismology. The use of seismic data helps providing stringent constraints on the stellar properties which directly impact the results of planetary studies. Amongst the most interesting planetary systems discovered by Kepler, Kepler-444 is unique by the quality of its seismic and classical stellar constraints. Its magnitude, age and the presence of 5 small-sized planets orbiting this target makes it an exceptional testbed for exoplanetology. <BR /> Aims: We aim at providing a detailed characterization of Kepler-444, focusing on the dependency of the results on variations of key ingredients of the theoretical stellar models. This thorough study will serve as a basis for future investigations of the planetary evolution of the system orbiting Kepler-444. <BR /> Methods: We use local and global minimization techniques to study the internal structure of the exoplanet-host star Kepler-444. We combine seismic observations from the Kepler mission, Gaia DR2 data, and revised spectroscopic parameters to precisely constrain its internal structure and evolution. <BR /> Results: We provide updated robust and precise determinations of the fundamental parameters of Kepler-444 and demonstrate that this low-mass star bore a convective core during a significant portion of its life on the main sequence. Using seismic data, we are able to estimate the lifetime of the convective core to approximately 8 Gyr out of the 11 Gyr of the evolution of Kepler-444. The revised stellar parameters found by our thorough study are M = 0.754 ± 0.03 M[SUB]☉[/SUB], R = 0.753 ± 0.01 R[SUB]☉[/SUB], and Age = 11 ± 1 Gyr.
Research center :
STAR - Space sciences, Technologies and Astrophysics Research - ULiège
Disciplines :
Space science, astronomy & astrophysics
Author, co-author :
Buldgen, Gaël ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Farnir, Martin ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Pezzotti, C.; Observatoire de Genève, Université de Genève, 51 Ch. Des Maillettes, 1290, Sauverny, Switzerland
Eggenberger, P.; Observatoire de Genève, Université de Genève, 51 Ch. Des Maillettes, 1290, Sauverny, Switzerland
Salmon, Sébastien ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Astrophysique stellaire théorique et astérosismologie
Montalban, J.; School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
Ferguson, J. W.; Department of Physics, Wichita State University, Wichita, KS, 67260-0032, USA
Khan, S.; School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
Bourrier, V.; Observatoire de Genève, Université de Genève, 51 Ch. Des Maillettes, 1290, Sauverny, Switzerland
Rendle, B. M.; School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
Meynet, G.; Observatoire de Genève, Université de Genève, 51 Ch. Des Maillettes, 1290, Sauverny, Switzerland
Miglio, A.; School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
Noels-Grötsch, Arlette ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO)
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