Souto, DiogoUnterborn, Cayman T.Smith, Verne V.Cunha, KatiaTeske, JohannaCovey, KevinRojas-Ayala, BárbaraGarcía-Hernández D.A.Stassun, Keivank, I.Zamora, OlgaMasseron, ThomasJohnson J.A.Majewski, Steven R.Jönsson, HenrikGilhool, StevenBlake, CullenSantana, Felipe2022-07-292022-07-292018-06Astrophysical Journal Letters Volume 860, Issue 110 June 2018 Article number L1520418205https://repositorio.unab.cl/xmlui/handle/ria/23380Indexación ScopusThe first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 μm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T eff = 3231 ±100 K, log g = 4.96 ±0.11 dex and chemical abundances of eight elements (C, O, Mg, Al, K, Ca, Ti, and Fe), finding Ross 128 to have near solar metallicity ([Fe/H] = +0.03 ± 0.09 dex). The derived results were obtained via spectral synthesis (1D LTE) adopting both MARCS and PHOENIX model atmospheres; stellar parameters and chemical abundances derived from the different adopted models do not show significant offsets. Mass-radius modeling of Ross 128b indicates that it lies below the pure-rock composition curve, suggesting that it contains a mixture of rock and iron, with the relative amounts of each set by the ratio of Fe/Mg. If Ross 128b formed with a subsolar Si abundance, and assuming the planet's composition matches that of the host star, it likely has a larger core size relative to the Earth despite this producing a planet with a Si/Mg abundance ratio ∼34% greater than the Sun. The derived planetary parameters - insolation flux (S Earth = 1.79 ±0.26) and equilibrium temperature (T eq = 294 ±10 K) - support previous findings that Ross 128b is a temperate exoplanet in the inner edge of the habitable zone. © 2018. The American Astronomical Society. All rights reserved.enExoplanetsKeplerAtmosphereplanetstar interactionsArtículoCC BY 4.010.3847/2041-8213/aac896