SIMBAD references

The gravity-brightening exponent (β) is studied using the UMA (Uppsala Model Atmosphere) code in non-illuminated convective grey (in the sense of ``continuum only'' opacity) and non-grey (line blanketed) atmospheres, for 3700K<T<sub>eff</sub><7000K. The value β=0.32 proposed by Lucy was confirmed only for T<sub>eff</sub>∼6500K. β depends upon T<sub>eff</sub> (an analytical expression is given), being rather insensitive to variations of the mixing length parameter, of the stellar mass and to the use of grey or non-grey atmospheres. A comparison with empirical determinations and a preliminary test of the use of the proposed β values in eclipsing binary light curve analysis are presented. A dependence of β on external illumination (``reflection effect'') for convective models is evidenced for the first time, the larger the amount of incident flux the larger the β exponent.