Astronomy and Astrophysics
Aims: We present a description of the STEPARSYN code and test its performance against a sample of late-type stars that were observed with the HERMES spectrograph mounted at the 1.2-m Mercator Telescope. This sample contains 35 late-type targets with well-known stellar parameters determined independently from spectroscopy. The code is available to the astronomical community in a GitHub repository.
Methods: STEPARSYN uses a Markov chain Monte Carlo sampler to explore the parameter space by comparing synthetic model spectra generated on the fly to the observations. The synthetic spectra are generated with an spectral emulator.
Results: We computed Teff, log g, and [Fe/H] for our sample stars and discussed the performance of the code. We calculated an internal scatter for these targets of −12 ± 117 K in Teff, 0.04 ± 0.14 dex in log g, and 0.05 ± 0.09 dex in [Fe/H]. In addition, we find that the log g values obtained with STEPARSYN are consistent with the trigonometric surface gravities to the 0.1 dex level. Finally, STEPARSYN can compute stellar parameters that are accurate down to 50 K, 0.1 dex, and 0.05 dex for Teff, log g, and [Fe/H] for stars with v sin i ≤ 30 km s−1. Full Table A.5 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/657/A66 Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.
Recientemente se han llevado a cabo varios análisis espectroscópicos de estrellas con planetas. Uno de los resultados más relevantes ha sido descubrir que las estrellas con planetas son en promedio más metálicas que las estrellas del mismo tipo espectral sin planetas conocidos (Santos, Israelian & Mayor 2001, A&A, 373, 1019; 2004, A&A, 415, 1153)