OPTICAL-IDENTIFICATION OF IRAS SOURCES IN THE OUTER GALAXY

The optical identifications at both V and I bands are given of 102 col or-selected IRAS PSC sources in the outer disk of our Galaxy. The posi tions were obtained from CCD images by using stars in the same frame a nd listed in the GSC catalogue (Guide Star Catalogue for Hubble Space Telescope) as references. The identification was judged from the consi stency with IRAS parameters in three aspects: the position, color, and light variation. About 50% of these sources are found to have optical counterpart. We identified 47 sources as variable stars, 2 as nonvari able stars. There are 1 star that has not been checked for light varia tion and 9 sources associated with nebulosity in the sample. We did no t find optical counterparts for 43 sources until 20 mag at V band and 19 mag at I band. The data suggest that whether or not an IRAS PSC sou rce can be optically identified results from not only the IRAS colors but also the C/O abundance in such a way that an oxygen-rich source ma y be more likely to be identified than a carbon-rich source. (C) 1996 American Astronomical Society.