Data-Driven Spectroscopy of Cool Stars at High Spectral Resolution

Abstract

The advent of large-scale spectroscopic surveys underscores the need to develop robust techniques for determining stellar properties ("labels", i.e., physical parameters and elemental abundances). However, traditional spectroscopic methods that utilize stellar models struggle to reproduce cool ($<$4700 K) stellar atmospheres due to an abundance of unconstrained molecular transitions, making modeling via synthetic spectral libraries difficult. Because small, cool stars such as K and M dwarfs are both common and good targets for finding small, cool planets, establishing precise spectral modeling techniques for these stars is of high priority. To address this, we apply The Cannon, a data-driven method of determining stellar labels, to Keck High Resolution Echelle Spectrometer (HIRES) spectra of 141 cool ($<$5200 K) stars from the California Planet Search. Our implementation is capable of predicting labels for small ($<$1 $R_{\odot }$) stars of spectral types K and later with accuracies of 68 K in effective temperature ($T_{eff}$), 5% in stellar radius ($R_{\ast }$), and 0.08 dex in bulk metallicity ([Fe/H]), and maintains this performance at low spectral resolutions ($R$ $<$ 5000). As M-dwarfs are the focus of many future planet-detection surveys, this work can aid efforts to better characterize the cool star population and uncover correlations between cool star abundances and planet occurrence for constraining planet formation theories.

arXiv comment9 pages, 7 figures. Accepted for publication in The Astrophysical Journal

References in corpus (22)

• The Dartmouth Stellar Evolution Database
• The Radial Velocity Experiment (RAVE): first data release
• How to Constrain Your M Dwarf: measuring effective temperature, bolometric luminosity, mass, and radius
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• The California Planet Survey I. Four New Giant Exoplanets
• A library of high resolution synthetic stellar spectra from 300nm to 1.8 micron with solar and alpha-enhanced composition
• Spectroscopy Made Easy: Evolution
• The Cannon: A data-driven approach to stellar label determination
• Metallicity and Temperature Indicators in M dwarf K band Spectra: Testing New & Updated Calibrations With Observations of 133 Solar Neighborhood M dwarfs
• Spectral Properties of Cool Stars: Extended Abundance Analysis of 1617 Planet Search Stars
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• Near-infrared Metallicities, Radial Velocities and Spectral Types for 447 Nearby M Dwarfs
• Improved Modeling of the Rossiter-McLaughlin Effect for Transiting Exoplanets
• Stellar Diameters and Temperatures V. Eleven Newly Characterized Exoplanet Host Stars
• Label Transfer from APOGEE to LAMOST: Precise Stellar Parameters for 450,000 LAMOST Giants
• An empirical calibration to estimate cool dwarf fundamental parameters from H-band spectra
• Accurate M Dwarf Metallicities from Spectral Synthesis: A Critical Test of Model Atmospheres
• Prospecting in Ultracool Dwarfs: Measuring the Metallicities of Mid- and Late-M Dwarfs
• Accurate Gravities of F, G, and K stars from High Resolution Spectra Without External Constraints
• Two Exoplanets Discovered at Keck Observatory
• The Gold Standard: Accurate Stellar and Planetary Parameters for Eight Kepler M dwarf Systems Enabled by Parallaxes
• Modification of the MOOG spectral synthesis codes to account for Zeeman broadening of spectral lines

Cited by in corpus (8)

• Temperatures and Metallicities of M dwarfs in the APOGEE Survey
• Stellar Characterization of Keck HIRES Spectra with The Cannon
• The Swan: Data-Driven Inference of Stellar Surface Gravities for Cool Stars from Photometric Light Curves
• Fundamental Parameters of $\sim$30,000 M dwarfs in LAMOST DR1 Using Data-driven Spectral Modeling
• Cool and Data-Driven: An Exploration of Optical Cool Dwarf Chemistry with Both Data-Driven and Physical Models
• Unravelling sub-stellar magnetospheres
• A Data-driven Spectral Model of Main Sequence Stars in Gaia DR3
• Using Old and New Approaches: Determining Physical Properties of Brown Dwarfs with Empirical Relations and Machine Learning Models