New absolute magnitude calibrations for detached binaries

Lutz-Kelker bias corrected absolute magnitude calibrations for the detached binary systems with main-sequence components are presented. The absolute magnitudes of the calibrator stars were derived at intrinsic colours of Johnson-Cousins and 2MASS (Two Micron All Sky Survey) photometric systems. As for the calibrator stars, 44 detached binaries were selected from the Hipparcos catalogue, which have relative observed parallax errors smaller than 15% (sigma(pi)/pi <= 0.15). The calibration equations which provide the corrected absolute magnitude for optical and near-infrared pass bands are valid for wide ranges of colours and absolute magnitudes: -0.18 < (B - V)(0) < 0.91, -1.6 < M-V < 5.5 and -0.15 < (J - H)(0) < 0.50, -0-02 < (H - K-s)(0) < 0. 13, 0 < M-J < 4, respectively. The distances computed using the luminosity-colours (LCs) relation with optical (B V) and near-infrared (J H K-s) observations were compared to the distances found from various other methods. The results show that new absolute magnitude calibrations of this study can be used as a convenient statistical tool to estimate the true distances of detached binaries out of Hipparcos' distance limit. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim