Anomalous dust in the environment of Herbig Ae/Be stars

Abstract

Photometric data in the UBVRI bands of Herbig Ae/Be stars have been analyzed to study the wavelength dependence of extinction to these objects. The color excess ratios E(U-B)/E(B-V), E(V-R)/E(B-V), E(V-I)/E(B-V) and E(V-I)/E(V-R) for these stars have been computed and compared with those for the mean interstellar extinction. The color excess ratios for Herbig Ae/Be stars are found to be anomalous. For a majority of the Herbig Ae/Be stars the values of the color excess ratios imply that the dust causing extinction to these stars is dominated by grains that are larger in size than the average dust grain in the interstellar medium.