The physical mechanism behind M dwarf metallicity indicators and the role of C and O abundances
| Autor: | Mark J. Veyette, Philip S. Muirhead, Andrew W. Mann, France Allard |
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| Přispěvatelé: | Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| Rok vydání: | 2016 |
| Předmět: |
stars: abundances
Metallicity Brown dwarf FOS: Physical sciences Context (language use) Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Spectral line stars: low-mass 0103 physical sciences stars: atmospheres Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Solar and Stellar Astrophysics (astro-ph.SR) Physics 010308 nuclear & particles physics stars: late-type Stellar atmosphere Astronomy and Astrophysics Stars Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science [SDU]Sciences of the Universe [physics] Magnitude (astronomy) Spectral energy distribution stars: fundamental parameters Astrophysics::Earth and Planetary Astrophysics brown dwarfs |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, 2016, 828, ⟨10.3847/0004-637X/828/2/95⟩ |
| ISSN: | 0004-637X 1538-4357 |
| DOI: | 10.48550/arxiv.1605.04904 |
| Popis: | We present NIR synthetic spectra based on PHOENIX stellar atmosphere models of typical early and mid M dwarfs with varied C and O abundances. We apply multiple recently published methods for determining M dwarf metallicity to our models to determine the effect of C and O abundances on metallicity indicators. We find that the pseudo-continuum level is very sensitive to C/O and that all metallicity indicators show a dependence on C and O abundances, especially in lower Teff models. In some cases the inferred metallicity ranges over a full order of magnitude (>1 dex) when [C/Fe] and [O/Fe] are varied independently by +/-0.2. We also find that [(O-C)/Fe], the difference in O and C abundances, is a better tracer of the pseudo-continuum level than C/O. Models of mid-M dwarfs with [C/Fe], [O/Fe], and [M/H] that are realistic in the context of galactic chemical evolution suggest that variation in [(O-C)/Fe] is the primary physical mechanism behind the M dwarf metallicity tracers investigated here. Empirically calibrated metallicity indicators are still valid for most nearby M dwarfs due to the tight correlation between [(O-C)/Fe] and [Fe/H] evident in spectroscopic surveys of solar neighborhood FGK stars. Variations in C and O abundances also affect the spectral energy distribution of M dwarfs. Allowing [O/Fe] to be a free parameter provides better agreement between synthetic spectra and observed spectra of metal-rich M dwarfs. We suggest that flux-calibrated, low-resolution, NIR spectra can provide a path toward measuring C and O abundances in M dwarfs and breaking the degeneracy between C/O and [Fe/H] present in M dwarf metallicity indicators. accepted for publication in ApJ, all synthetic spectra available at http://people.bu.edu/mveyette/phoenix/, v2 - corrected figures 1 and 2 y-axis |
| Databáze: | OpenAIRE |
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