VERY-LOW MASS STARS - NONLINEARITY OF THE LIMB-DARKENING LAWS

Linear and non-linear limb-darkening coefficients for the photometric bands u v b y U B V R I J H K are computed for very low effective temp eratures stars. The atmosphere models used (PHOENIX-NextGen) do not in clude the effects of dust formation and dust opacities. These calculat ions are presented for the first time. The calculations extend the ran ge of effective temperatures (2000 K - 50000 It) covered by our previo us papers. These data are important in order to deal with stars in the lower part of Main-Sequence like M or brown dwarfs. The nonlinear beh avior of the limb-darkening lau's, particularly in this effective temp erature range, is emphasized and we urge users to take it into account .