Cool and Data-Driven: An Exploration of Optical Cool Dwarf Chemistry with Both Data-Driven and Physical Models

Abstract

Detailed chemical studies of F/G/K -- or Solar-type -- stars have long been routine in stellar astrophysics, enabling studies in both Galactic chemodynamics, and exoplanet demographics. However, similar understanding of the chemistry of M and late-K dwarfs -- the most common stars in the Galaxy -- has been greatly hampered both observationally and theoretically by the complex molecular chemistry of their atmospheres. Here we present a new implementation of the data-driven \textit{Cannon} model, modelling $T_{\mathrm{eff}}$, $\log g$, [Fe/H], and [Ti/Fe] trained on low-medium resolution optical spectra ($4000-7000$\SI{}{\angstrom}) from 103 cool dwarf benchmarks. Alongside this, we also investigate the sensitivity of optical wavelengths to various atomic and molecular species using both data-driven and theoretical means via a custom grid of MARCS synthetic spectra, and make recommendations for where MARCS struggles to reproduce cool dwarf fluxes. Under leave-one-out cross-validation, our \textit{Cannon} model is capable of recovering $T_{\mathrm{eff}}$, $\log g$, [Fe/H], and [Ti/Fe] with precisions of 1.4\%, $\pm 0.04$dex, $\pm 0.10$dex, and $\pm 0.06$dex respectively, with the recovery of [Ti/Fe] pointing to the as-yet mostly untapped potential of exploiting the abundant -- but complex -- chemical information within optical spectra of cool stars.

24 pages, 14 figures, 4 tables. Accepted for publication in MNRAS

References in corpus (45)

• Array Programming with NumPy
• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• The Transiting Exoplanet Survey Satellite
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The K2 Mission: Characterization and Early results
• The mass distribution and gravitational potential of the Milky Way
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes
• One or more bound planets per Milky Way star from microlensing observations
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• 4MOST: Project overview and information for the First Call for Proposals
• CH in stellar atmospheres: an extensive linelist
• Trumpeting M Dwarfs with CONCH-SHELL: a Catalog of Nearby Cool Host-Stars for Habitable ExopLanets and Life
• The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample
• The Solar Neighborhood XXXV: Distances to 1404 M Dwarf Systems Within 25 pc in the Southern Sky
• A search for TiO in the optical high-resolution transmission spectrum of HD 209458b: Hindrance due to inaccuracies in the line database
• Metallicities of M Dwarf Planet Hosts from Spectral Synthesis
• Accurate M Dwarf Metallicities from Spectral Synthesis: A Critical Test of Model Atmospheres
• Identical or fraternal twins? : The chemical homogeneity of wide binaries from Gaia DR2
• The lowest detected stellar Fe abundance: The halo star SMSS J160540.18-144323.1
• HADES RV Programme with HARPS-N at TNG XII. The abundance signature of M dwarf stars with planets
• A discontinuity in the $T_{\mathrm{eff}}$-radius relation of M-dwarfs
• Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186
• Chemical evidence for planetary ingestion in a quarter of Sun-like stars
• Energy transport, overshoot, and mixing in the atmospheres of M-type main- and pre-main-sequence objects
• Stellar Characterization of M-dwarfs from the APOGEE Survey: A Calibrator Sample for the M-dwarf Metallicities
• A physically motivated and empirically calibrated method to measure effective temperature, metallicity, and Ti abundance of M dwarfs
• Detailed Chemical Abundances for a Benchmark Sample of M Dwarfs from the APOGEE Survey
• A blue depression in the optical spectra of M dwarfs
• Metallicity determination of M dwarfs - Expanded parameter range in metallicity and effective temperature
• Stellar parametrization of LAMOST M dwarf stars
• Stellar Characterization of Keck HIRES Spectra with The Cannon
• Estimating the atmospheric properties of 44 M dwarfs from SPIRou spectra
• Elemental abundances of nearby M dwarfs based on high-resolution near-infrared spectra obtained by the Subaru/IRD survey: Proof of concept
• Estimating fundamental parameters of nearby M dwarfs from SPIRou spectra
• Near Infrared Spectroscopy of M Dwarfs. I. CO Molecule as an Abundance Indicator of Carbon
• Near Infrared Spectroscopy of M Dwarfs. II. H2O Molecule as an Abundance Indicator of Oxygen
• AlH lines in the blue spectrum of Proxima Centauri
• Optical - Near Infrared Photometric Calibration of M-dwarf Metallicity and Its Application
• A data-driven model of nucleosynthesis with chemical tagging in a lower-dimensional latent space
• Data-Driven Spectroscopy of Cool Stars at High Spectral Resolution
• Photometric Calibrations of M-dwarf Metallicity with Markov Chain Monte Carlo and Bayesian Inference
• A spectroscopically confirmed Gaia-selected sample of 318 new young stars within $\sim$200 pc
• Near infrared spectroscopy of M dwarfs. IV. A preliminary survey on the carbon isotopic ratios in M dwarfs

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• Performance of the Stellar Abundances and atmospheric Parameters Pipeline adapted for M dwarfs I. Atmospheric parameters from the spectroscopic module
• Abundance analysis of benchmark M dwarfs
• Estimating Stellar Atmospheric Parameters and [α/Fe] for LAMOST O-M type Stars Using a Spectral Emulator