• DOI:10.1093/mnras/stu2502
• Corpus ID: 1808077

Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs

@article{Boyajian2015StellarDA,
  title={Stellar diameters and temperatures - VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs},
  author={Tabetha S. Boyajian and Kaspar von Braun and Gregory A. Feiden and Daniel Huber and Sarbani Basu and Pierre. Demarque and Debra A. Fischer and Gail H. Schaefer and Andrew W. Mann and Timothy R. White and Vicente Maestro and John M. Brewer and C. Brooke Lamell and Federico Spada and Mercedes L'opez-Morales and Michael J. Ireland and Christopher D. Farrington and Gerard T. van Belle and Stephen R. Kane and Jeremy Jones and Theo A. ten Brummelaar and David R. Ciardi and Harold A. Mcalister and Stephen T. Ridgway and P. J. Goldfinger and Nils H. Turner and Laszlo Sturmann},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2015},
  volume={447},
  pages={846-857}
}

• T. Boyajian, K. Braun, +24 authors L. Sturmann
• Published 20 November 2014
• Physics, Geology
• Monthly Notices of the Royal Astronomical Society

We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limbdarkened angular diameters to be θLD = 0.3848 ± 0.0055 and 0.2254 ± 0.0072 mas for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion’s orbital motion from high-resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (Teff = 4875 ± 43, 6092 ± 103K), stellar linearradii(R∗ =0.805 ±0.016,1.203 ±0.061R� ),meanstellardensities(ρ∗ =1.62 ±0.11, 0.58 ± 0.14 ρ� ), planetary radii (Rp = 1.216 ± 0.024, 1.451 ± 0.074 RJup), and mean planetary densities (ρp = 0.605 ± 0.029, 0.196 ± 0.033 ρJup) for HD 189733b and HD 209458b, respectively. The stellar parameters for HD 209458, an F9 dwarf, are consistent with indirect estimates derived from spectroscopic and evolutionary modelling. However, we find that models are unable to reproduce the observational results for the K2 dwarf, HD 189733. We show that, for stellar evolutionary models to match the observed stellar properties of HD 189733, adjustments lowering the solar-calibrated mixing-length parameter to αMLT =1.34 need to be