The HD 137496 system: A dense, hot super-Mercury and a cold Jupiter
In: ISSN: 0004-6361, 2022
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International audience ; Context. Most of the currently known planets are small worlds with radii between that of the Earth and that of Neptune. The characterization of planets in this regime shows a large diversity in compositions and system architectures, with distributions hinting at a multitude of formation and evolution scenarios. However, many planetary populations, such as high-density planets, are significantly under-sampled, limiting our understanding of planet formation and evolution. Aims: NCORES is a large observing program conducted on the HARPS high-resolution spectrograph that aims to confirm the planetary status and to measure the masses of small transiting planetary candidates detected by transit photometry surveys in order to constrain their internal composition. Methods: Using photometry from the K2 satellite and radial velocities measured with the HARPS and CORALIE spectrographs, we searched for planets around the bright (V mag = 10) and slightly evolved Sun-like star HD 137496. Results: We precisely estimated the stellar parameters, M * = 1.035 ± 0.022 M ⊙ , R * = 1.587 ± 0.028 R ⊙ , T eff = 5799 ± 61 K, together with the chemical composition (e.g. [Fe/H] = −0.027 ± 0.040 dex) of the slightly evolved star. We detect two planets orbiting HD 137496. The inner planet, HD 137496 b, is a super-Mercury (an Earth-sized planet with the density of Mercury) with a mass of M b = 4.04 ± 0.55 M ⊕ , a radius of R b = 1.31 −0.05 +0.06 R ⊕ , and a density of ρ b = 10.49 −1.82 +2.08 g cm -3 . With an interior modeling analysis, we find that the planet is composed mainly of iron, with the core representing over 70% of the planet's mass (M core / M total = 0.73 −0.12 +0.11 ). The outer planet, HD 137496 c, is an eccentric (e = 0.477 ± 0.004), long period (P = 479.9 −1.1 +1.0 days) giant planet (M c sini c = 7.66 ± 0.11 M Jup ) for which we do not detect a transit. Conclusions: HD 137496 b is one of the few super-Mercuries detected to date. The accurate characterization reported here enhances its role as a key ...
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The HD 137496 system: A dense, hot super-Mercury and a cold Jupiter
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Autor/in / Beteiligte Person: | Azevedo Silva, T. ; Demangeon, O. D. S. ; Barros, S. C. C. ; Armstrong, D. J. ; Otegi, J. F. ; Bossini, D. ; Delgado Mena, E. ; Sousa, S. G. ; Adibekyan, V. ; Nielsen, L. D. ; Dorn, C. ; Lillo-Box, J. ; Santos, N. C. ; Hoyer, S. ; Stassun, K. G. ; Almenara, J. M. ; Bayliss, D. ; Barrado, D. ; Boisse, I. ; Brown, D. J. A. ; Díaz, R. F. ; Dumusque, X. ; Figueira, P. ; Hadjigeorghiou, A. ; Hojjatpanah, S. ; Mousis, O. ; Osborn, A. ; Santerne, A. ; Strøm, P. A. ; Udry, S. ; Wheatley, P. J. ; Instituto de Astrofísica e Ciências do Espaço (IASTRO) ; University of Warwick Coventry ; Laboratoire d'Astrophysique de Marseille (LAM) ; Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS) ; Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) ; Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ) ; Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France |
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Zeitschrift: | ISSN: 0004-6361, 2022 |
Veröffentlichung: | HAL CCSD ; EDP Sciences, 2022 |
Medientyp: | academicJournal |
DOI: | 10.1051/0004-6361/202141520 |
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