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The solar twin planet search I. Fundamental parameters of the stellar sample

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The solar twin planet search I. Fundamental parameters of the stellar sample

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Título The solar twin planet search I. Fundamental parameters of the stellar sample
Autor Ramírez, Iván
Meléndez, Jorge
Bean, Jacob L.
Asplund, Martin
Bedell, Megan
Monroe, TalaWanda Rose
Casagrande, Luca
Schirbel, Lucas Alexandre
Dreizler, Stefan
Teske, Johanna K.
Maia, Marcelo Tucci
Brito, Alan Alves
Baumann, P.
Abstract Context. We are carrying out a search for planets around a sample of solar twin stars using the HARPS spectrograph. The goal of this project is to exploit the advantage offered by solar twins to obtain chemical abundances of unmatched precision. This survey will enable new studies of the stellar composition – planet connection. Aims. We determine the fundamental parameters of the 88 solar twin stars that have been chosen as targets for our experiment. Methods. We used theMIKE spectrograph on the Magellan Clay Telescope to acquire high resolution, high signal-to-noise ratio spectra of our sample stars.We measured the equivalent widths of iron lines and used strict differential excitation/ionization balance analysis to determine atmospheric parameters of unprecedented internal precision: σ(Teff) = 7K, σ(log g) = 0.019, σ([Fe/H]) = 0.006 dex, σ(vt) = 0.016 km s−1. Reliable relative ages and highly precise masses were then estimated using theoretical isochrones Results. The spectroscopic parameters we derived are in good agreement with those measured using other independent techniques. There is even better agreement if the sample is restricted to those stars with the most internally precise determinations of stellar parameters in every technique involved. The root-mean-square scatter of the differences seen is fully compatible with the observational errors, demonstrating, as assumed thus far, that systematic uncertainties in the stellar parameters are negligible in the study of solar twins. We find a tight activity-age relation for our sample stars, which validates the internal precision of our dating method. Furthermore, we find that the solar cycle is perfectly consistent both with this trend and its star-to-star scatter. Conclusions. We present the largest sample of solar twins analyzed homogeneously using high quality spectra. The fundamental parameters derived from this work will be employed in subsequent work that aims to explore the connections between planet formation and stellar chemical composition.
Contido em Astronomy and astrophysics. Les Ulis. Vol. 572 (Dec. 2014), A48, 19 p.
Assunto Composicao estelar
Espectros estelares
Planetas extrasolares
[en] Planetary systems
[en] Stars: abundances
[en] Stars: fundamental parameters
Origem Estrangeiro
Tipo Artigo de periódico
URI http://hdl.handle.net/10183/140322
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