TY - JOUR
T1 - Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
AU - Souto, Diogo
AU - Unterborn, Cayman T.
AU - Smith, Verne V.
AU - Cunha, Katia
AU - Teske, Johanna
AU - Covey, Kevin
AU - Rojas-Ayala, Bárbara
AU - García-Hernández, D. A.
AU - Stassun, Keivan
AU - Zamora, Olga
AU - Masseron, Thomas
AU - Johnson, J. A.
AU - Majewski, Steven R.
AU - Jönsson, Henrik
AU - Gilhool, Steven
AU - Blake, Cullen
AU - Santana, Felipe
N1 - Publisher Copyright:
© 2018. The American Astronomical Society. All rights reserved.
PY - 2018/6/10
Y1 - 2018/6/10
N2 - The 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.
AB - The 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.
KW - infrared: stars
KW - planetary systems
KW - planetstar interactions
KW - stars: abundances
KW - stars: fundamental parameters
KW - stars: low-mass
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U2 - 10.3847/2041-8213/aac896
DO - 10.3847/2041-8213/aac896
M3 - Article
AN - SCOPUS:85049052764
SN - 2041-8205
VL - 860
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 1
M1 - L15
ER -