J/A+A/671/A171 PySME. Spectroscopy Made Easier (Wehrhahn+, 2023)
PySME. Spectroscopy Made Easier.
Wehrhahn A., Piskunov N., Ryabchikova T.
<Astron. Astrophys. 671, A171 (2023)>
=2023A&A...671A.171W 2023A&A...671A.171W (SIMBAD/NED BibCode)
ADC_Keywords: Stars, F-type ; Stars, G-type ; Stars, K-type ; Spectroscopy ;
Effective temperatures ; Abundances, [Fe/H] ;
Rotational velocities ; Optical
Keywords: techniques: spectroscopic - methods: data analysis -
methods: numerical - stars: fundamental parameters - stars: solar-type
Abstract:
The characterization of exoplanets 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 and other
techniques. We show that PySME works at least as well as the original
SME.
Description:
Fundamental parameters derived from high resolution spectroscopic
observations with HARPS using the PySME code. Two uncertainty measures
are given, the fit uncertainty as derived by the least squares fitting
algorithm, and the SME uncertainty using the method described in the
paper.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
pysme.dat 406 8 Stellar parameters of the sample discussed
in the paper
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Byte-by-byte Description of file: pysme.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Name Name of the target star (name)
10- 11 I2 h RAh Right ascension (J2000)
13- 14 I2 min RAm Right ascension (J2000)
16- 28 F13.10 s RAs Right ascension (J2000)
30 A1 --- DE- Declination sign (J2000)
31- 32 I2 deg DEd Declination (J2000)
34- 35 I2 arcmin DEm Declination (J2000)
37- 48 F12.9 arcsec DEs Declination (J2000)
50- 67 F18.13 K Teff Effective temperature (teff)
69- 86 F18.16 K e1_Teff fit uncertainty of the effective temperature
(fituncertaintyteff)
88-105 F18.14 K e2_Teff SME uncertainty of the effective temperature
(smeuncertaintyteff)
107-123 F17.15 [cm/s2] logg Surface gravity (logg)
125-145 F21.19 [cm/s2] e1_logg fit uncertainty of the surface gravity
(fituncertaintylogg)
147-164 F18.16 [cm/s2] e2_logg SME uncertainty of the surface gravity
(smeuncertaintylogg)
166-185 F20.17 [-] [M/H] Metallicity [M/H] in H=12 format (monh)
187-207 F21.19 [-] e1_[M/H] fit uncertainty of the metallicity
(fituncertaintymonh)
209-227 F19.17 [-] e2_[M/H] SME uncertainty of the metallicity
(smeuncertaintymonh)
229-246 F18.16 km/s vmic Micro turbulence parameter (vmic)
248-268 F21.19 km/s e1_vmic fit uncertainty of the micro turbulence
parameter (fituncertaintyvmic)
270-287 F18.16 km/s e2_vmic SME uncertainty of the micro turbulence
parameter (smeuncertaintyvmic)
289-306 F18.16 km/s vmac macro turbulence parameter (vmac)
308-327 F20.18 km/s e1_vmac fit uncertainty of the macro turbulence
parameter (fituncertaintyvmac)
329-346 F18.16 km/s e2_vmac SME uncertainty of the macro turbulence
parameter (smeuncertaintyvmac)
348-365 F18.15 km/s vsini Projected rotational velocity (vsini)
367-386 F20.18 km/s e1_vsini fit uncertainty of the projected rotational
velocity (fituncertaintyvsini)
388-406 F19.15 km/s e2_vsini SME uncertainty of the projected rotational
velocity (smeuncertaintyvsini)
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History:
From Ansgar Wehrhahn, ansgar.wehrhahn(at)hotmail.de
Acknowledgements:
This research has made use of the services of the ESO Science Archive
Facility. Based on observations collected at the European Southern
Observatory under ESO programs 60.A-9036(A), 192.C-0224(A),
083.C-0794(A), 072.C-0488(E), 288.C-5010(A), 0104.C-0849(A), and
098.C-0739(A). This work has made use of the VALD database, operated
at Uppsala University, the Institute of Astronomy RAS in Moscow, and
the University of Vienna.
(End) Patricia Vannier [CDS] 13-Dec-2022