A New Spectroscopic and Photometric Analysis of the Transiting Planet Systems TrES-3 and TrES-4

Sozzetti, Alessandro; Torres, Guillermo; Charbonneau, David; Winn, Joshua N.; Korzennik, Sylvain G.; Holman, Matthew J.; Latham, David W.; Laird, John B.; Fernandez, José; O'Donovan, Francis T. et al.
Bibliographical reference

The Astrophysical Journal, Volume 691, Issue 2, pp. 1145-1158 (2009).

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We report new spectroscopic and photometric observations of the parent stars of the recently discovered transiting planets TrES-3 and TrES-4. A detailed abundance analysis based on high-resolution spectra yields [Fe/H] = -0.19 ± 0.08, T eff = 5650 ± 75 K, and log g = 4.4 ± 0.1 for TrES-3, and [Fe/H] = +0.14 ± 0.09, T eff = 6200 ± 75 K, and log g = 4.0 ± 0.1 for TrES-4. The accuracy of the effective temperatures is supported by a number of independent consistency checks. The spectroscopic orbital solution for TrES-3 is improved with our new radial velocity measurements of that system, as are the light-curve parameters for both systems based on newly acquired photometry for TrES-3 and a reanalysis of existing photometry for TrES-4. We have redetermined the stellar parameters taking advantage of the strong constraint provided by the light curves in the form of the normalized separation a/R sstarf (related to the stellar density) in conjunction with our new temperatures and metallicities. The masses and radii we derive are M sstarf = 0.928+0.028 -0.048 M sun, R sstarf = 0.829+0.015 -0.022 R sun, and M sstarf = 1.404+0.066 -0.134 M sun, R sstarf = 1.846+0.096 -0.087 R sun for TrES-3 and TrES-4, respectively. With these revised stellar parameters, we obtain improved values for the planetary masses and radii. We find Mp = 1.910+0.075 -0.080 M Jup, Rp = 1.336+0.031 -0.036 R Jup for TrES-3, and Mp = 0.925 ± 0.082 M Jup, Rp = 1.783+0.093 -0.086 R Jup for TrES-4. We confirm TrES-4 as the planet with the largest radius among the currently known transiting hot Jupiters.
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The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary