NGTS-21b: an inflated Super-Jupiter orbiting a metal-poor K dwarf
| Autor: | Douglas R Alves, James S Jenkins, Jose I Vines, Louise D Nielsen, Samuel Gill, Jack S Acton, D R Anderson, Daniel Bayliss, François Bouchy, Hannes Breytenbach, Edward M Bryant, Matthew R Burleigh, Sarah L Casewell, Philipp Eigmüller, Edward Gillen, Michael R Goad, Maximilian N Günther, Beth A Henderson, Alicia Kendall, Monika Lendl, Maximiliano Moyano, Ramotholo R Sefako, Alexis M S Smith, Jean C Costes, Rosanne H Tilbrook, Jessymol K Thomas, Stéphane Udry, Christopher A Watson, Richard G West, Peter J Wheatley, Hannah L Worters, Ares Osborn |
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| Přispěvatelé: | 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) |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: |
Earth and Planetary Astrophysics (astro-ph.EP)
techniques: photometric planets and satellites: detection [SDU]Sciences of the Universe [physics] Space and Planetary Science techniques: radial velocities FOS: Physical sciences Astronomy and Astrophysics planets and satellites: general planets and satellites: fundamental parameters stars: general Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | Monthly Notices of the Royal Astronomical Society Monthly Notices of the Royal Astronomical Society, 2023, 517, pp.4447-4457. ⟨10.1093/mnras/stac2884⟩ |
| ISSN: | 0035-8711 1365-2966 |
| DOI: | 10.1093/mnras/stac2884⟩ |
| Popis: | We report the discovery of NGTS-21b, a massive hot Jupiter orbiting a low-mass star as part of the Next Generation Transit Survey (NGTS). The planet has a mass and radius of $2.36 \pm 0.21$ M$_{\rm J}$, and $1.33 \pm 0.03$ R$_{\rm J}$, and an orbital period of 1.543 days. The host is a K3V ($T_{\rm eff}=4660 \pm 41$, K) metal-poor (${\rm [Fe/H]}=-0.26 \pm 0.07$, dex) dwarf star with a mass and radius of $0.72 \pm 0.04$, M$_{\odot}$,and $0.86 \pm 0.04$, R$_{\odot}$. Its age and rotation period of $10.02^{+3.29}_{-7.30}$, Gyr and $17.88 \pm 0.08$, d respectively, are in accordance with the observed moderately low stellar activity level. When comparing NGTS-21b with currently known transiting hot Jupiters with similar equilibrium temperatures, it is found to have one of the largest measured radii despite its large mass. Inflation-free planetary structure models suggest the planet's atmosphere is inflated by $\sim21\%$, while inflationary models predict a radius consistent with observations, thus pointing to stellar irradiation as the probable origin of NGTS-21b's radius inflation. Additionally, NGTS-21b's bulk density ($1.25 \pm 0.15$, g/cm$^3$) is also amongst the largest within the population of metal-poor giant hosts ([Fe/H] < 0.0), helping to reveal a falling upper boundary in metallicity-planet density parameter space that is in concordance with core accretion formation models. The discovery of rare planetary systems such as NGTS-21 greatly contributes towards better constraints being placed on the formation and evolution mechanisms of massive planets orbiting low-mass stars. 12 pages, 13 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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