Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
Unterborn, Cayman T.
Smith, Verne V.
García-Hernández, D. A.
Johnson, J. A.
Majewski, Steven R.
AffiliationUniv Arizona, Steward Observ
stars: fundamental parameters
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationDiogo Souto et al 2018 ApJL 860 L15
JournalASTROPHYSICAL JOURNAL LETTERS
Rights© 2018. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractThe 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 mu m), high-resolution (R similar to 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 similar to 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.
VersionFinal published version
SponsorsNational Aeronautics and Space Administration [16-XRP16\_2-0004]; NSF [AST-1616636]; CONICYT PAI/CONCURSO NACIONAL INSERCION EN LA ACADEMIA, CONVOCATORIA ; Crafoord Foundation; Stiftelsen Olle Engkvist Byggmastare; NASA - Space Telescope Science Institute [HST-HF2-51399.001, NAS5-26555]; National Aeronautics and Space Administration; Alfred P. Sloan Foundation; U.S. Department of Energy Office of Science; Center for High-Performance Computing at the University of Utah; Brazilian Participation Group; Carnegie Institution for Science, Carnegie Mellon University; Chilean Participation Group; French Participation Group; Harvard-Smithsonian Center for Astrophysics; Instituto de Astrofisica de Canarias; The Johns Hopkins University; Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo; Lawrence Berkeley National Laboratory; Leibniz Institut fur Astrophysik Potsdam (AIP); Max-Planck-Institut fur Astronomie (MPIA Heidelberg); Max-Planck-Institut fur Astrophysik (MPA Garching); Max-Planck-Institut fur Extraterrestrische Physik (MPE); National Astronomical Observatory of China; New Mexico State University; New York University; University of Notre Dame; Observatorio Nacional/MCTI; Ohio State University; Pennsylvania State University; Shanghai Astronomical Observatory; United Kingdom Participation Group; Universidad Nacional Autonoma de Mexico; University of Arizona; University of Colorado Boulder; University of Oxford; University of Portsmouth; University of Utah; University of Virginia; University of Washington; University of Wisconsin; Vanderbilt University; Yale University; Spanish Ministry of Economy and Competitiveness (MINECO) [AYA-2017-88254-P]