http://arxiv.org/abs/1611.09976
In this study we investigate the calibration of surface brightness — color (SBC) relations based solely on eclipsing binary stars. We selected a sample of 35 detached eclipsing binaries having trigonometric parallaxes from Gaia DR1 or Hipparcos, their absolute dimensions known with an accuracy better than 3\% and lying within 0.3 kpc from the Sun. For the purpose of this study we used mostly homogeneous optical and near-infrared photometry based on Tycho-2 and 2MASS catalogues. We derived geometric angular diameters for all stars in our sample with precision better than 10\%, and for 11 of them with precision better than 2\%. At the present moment the precision of individual angular diameters of the eclipsing binary components is limited by the precision of the geometric distances ($\sim$5\% on average). However by using a sub-sample of systems with the best agreement between their geometric and photometric distances we derived the precise SBC relations based only on eclipsing binary stars. Those relations have precision comparable to the best available SBC relations based on interferometric angular diameters and they are fully consistent with them. With near-future very precise Gaia paralaxes angular diameters having precision better than 1\% will be abundant. At that point the main uncertainty in the total error budget of the SBC relations will come from transformations between different photometric systems, disentangling of components’ magnitudes and for hot OB stars from the interstellar extinction determination. We argue that all these issues can be overcome with modern high quality data and conclude that sub-percent precision is entirely feasible.
D. Graczyk, P. Konorski, G. Pietrzynski, et. al.
Thu, 1 Dec 16
14/75
Comments: submitted to the Astrophysical Journal. Comments welcome
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