PySME -- Spectroscopy Made Easier

Abstract

The characterization of exoplanet requires reliable determination of the fundamental parameters of their host stars. Spectral fitting plays an important role in this process. For the majority of stellar parameters matching synthetic spectra to the observations provides a robust and unique solution for fundamental parameters, such as effective temperature, surface gravity, abundances, radial and rotational velocities and others. Here we present a new software package for fitting high resolution stellar spectra that is easy to use, available for common platforms and free from commercial licenses. We call it PySME. It is based on the proven Spectroscopy Made Easy (later referred to as IDL SME or "original SME") package. The IDL part of the original SME code has been rewritten in Python, but we kept the efficient C++ and FORTRAN code responsible for molecular-ionization equilibrium, opacities and spectral synthesis. In the process we have updated some components of the optimization procedure offering more flexibility and better analysis of the convergence. The result is a more modern package with the same functionality of the original SME. We apply PySME to a few stars of different spectral types and compared the derived fundamental parameters with the results from IDL SME and other techniques. We show that PySME works at least as well as the original SME.

23 pages, 13 figures, code is available on https://github.com/AWehrhahn/SME

References in corpus (28)

• Array Programming with NumPy
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library
• A planet within the debris disk around the pre-main-sequence star AU Microscopii
• Discovery of Two T Dwarf Companions with the Spitzer Space Telescope
• CARMENES input catalogue of M dwarfs. I. Low-resolution spectroscopy with CAFOS
• Non-LTE line formation of Fe in late-type stars - III. 3D non-LTE analysis of metal-poor stars
• The Extrasolar Planet epsilon Eridani b - Orbit and Mass
• Improved Laboratory Transition Probabilities for Neutral Chromium and Re-determination of the Chromium Abundance for the Sun and Three Stars
• Improved Laboratory Transition Probabilities for Ce II, Application to the Cerium Abundances of the Sun and Five r-process Rich, Metal-Poor Stars, and Rare Earth Lab Data
• Non-LTE aluminium abundances in late-type stars
• Mg line formation in late-type stellar atmospheres: I. The model atom
• The GALAH Survey: Non-LTE departure coefficients for large spectroscopic surveys
• Improved Laboratory Transition Probabilities for Er II and Applications to the Erbium Abundances of the Sun and Five r-Process Rich, Metal-Poor Stars
• The solar silicon abundance based on 3D non-LTE calculations
• 3D NLTE spectral line formation of lithium in late-type stars
• A new Neptune-mass planet orbiting HD 219828
• Improved V II log($gf$) Values, Hyperfine Structure Constants, and Abundance Determinations in the Photospheres of the Sun and Metal-poor Star HD 84937
• Observational constraints on the origin of the elements II. 3D non-LTE formation of Ba ii lines in the solar atmosphere
• Non-LTE analysis of K I in late-type stars
• Non-LTE Radiative Transfer with Turbospectrum
• 3D non-LTE line formation of neutral carbon in the Sun
• Host star metallicity of directly imaged wide-orbit planets: implications for planet formation
• Spectroscopic parameters for solar-type stars with moderate/high rotation. New parameters for 10 planet-hosts
• Chemical abundances of 1111 FGK stars from the HARPS-GTO planet search sample. III. Sulfur
• Ca line formation in late-type stellar atmospheres: I. The model atom
• Refined Properties of the HD 130322 Planetary System
• Korg: a modern 1D LTE spectral synthesis package

Cited by in corpus (21)

• Vertical structure of an exoplanet's atmospheric jet stream
• An atlas of resolved spectral features in the transmission spectrum of WASP-189 b with MAROON-X
• Convective characteristics of Fe I lines across the solar disc
• Inferring stellar parameters and their uncertainties from high-resolution spectroscopy using invertible neural networks
• Quiet Please: Detrending Radial Velocity Variations from Stellar Activity with a Physically Motivated Spot Model
• Automatic line selection for abundance determination in large stellar spectroscopic surveys
• Exploring fluorine chemical evolution in the Galactic disk: the open cluster perspective
• A free-floating-planet microlensing event caused by a Saturn-mass object
• The GALAH survey: Improving chemical abundances using star clusters
• Stellar Population Astrophysics (SPA) with the TNG: NLTE atmospheric parameters and abundances of giant stars in 33 Open Clusters
• Gaia Barium Dwarfs and Their Ostensibly Ordinary Counterparts
• The solar sulphur abundance in view of large-scale atomic structure calculations and 3D non-LTE models
• Secrets in the shadow: High precision stellar abundances of fast-rotating A-type exoplanet host stars through transit spectroscopy
• Searching for new Hypervelocity Stars with Gaia DR3 and VLT/FORS2 Spectroscopy
• IK Pegasi and the Double-merger Path to Type Ia Supernovae
• A.C.I.D -- An Improved LSD Technique for Accurate Line Profile Retrieval
• Granulation on a quiet K dwarf: HD 166620 I. Spectral signatures as a function of line-formation temperature
• A method to derive self-consistent NLTE astrophysical parameters for 4 million high-resolution 4MOST stellar spectra in half a day with invertible neural networks
• Observational constraints on the origin of the elements. X. Combining NLTE and machine learning for chemical diagnostics of 4 million stars in the 4MIDABLE-HR survey
• Dynamical mass determination and partial eclipses of the heartbeat star HD 181793
• Unveiling the Variability and Chemical Composition of AL Col