New constraints from the Hα line for the temperature of the transiting planet host star OGLE-TR-10

M. Ammler-von Eiff, N. C. Santos

Resumo
The spectroscopic analysis of systems with transiting planets gives strong constraints  on planetary masses and radii as well as the chemical composition of the systems.  The properties of the system OGLE-TR-10 are not well-constrained, partly due to the  discrepancy of previous measurements of the effective temperature of the host star. This work, which is fully independent from previous works in terms of data reduction  and analysis, uses the Hα profile in order to get an additional constraint on the  effective temperature. We take previously published UVES observations which have the  highest available signal-to-noise ratio for OGLE-TR-10. A proper normalization to the  relative continuum is done using intermediate data products of the reduction  pipeline of the UVES spectrograph. The effective temperature then is determined by  fitting synthetic Hα profiles to the observed spectrum. With a result of Teff = 6020 ±  140 K, the Hα profile clearly favours one of the previous measurements. The Hα line is further consistent with dwarf-like surface gravities as well as solar and super-solar  metallicities previously derived for OGLE-TR-10.The Hα line could not be used to its full potential, partly because of the varying shape of the UVES echelle orders after flat field correction. We suggest to improve this feature when constructing future  spectrographs.

Astronomische Nachrichten
Volume 329, Página 573
julho 2008

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