An infrared study of Herbig Ae/Be stars

The IRAS and 2MASS associations for 206 HAEBE stars are identified in this paper. From the color-color diagrams and spectral index, it is found that the IR excesses for most samples are due to thermal emission from the circumstellar material. It is also found that the IR excesses at IRAS region for few HAEBE stars and the near-IR excesses for some HAEBE stars are likely attributed to free-free emission or free-bound emission from the circumstellar ionized gas. Moreover, the evolution scenario (from embedded HAEBE stars to β Pictoris-like main-sequence stars) from Malfait et al. (1998) has been checked, our result does not support this evolution scenario.This publication makes use of data products from the Two Micron All Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, founded by the National Aeronautics and Space Administration and the National Science Foundation of the United States.