IRAS SOURCES ASSOCIATED WITH SMALL NEBULAE IN STAR-FORMING REGIONS - OPTICAL AND NEAR-INFRARED IMAGES

Optical CCD and near-IR broad and narrow-band imaging have been obtain ed of a sample of 11 small optical nebula associated with IRAS sources in star forming regions in order to perform a morphological and photo metric study. More than 130 sources were detected in K. The J-H versus H-K diagram was used to establish their nature. The most massive regi ons, Gy 2-18, Gy 4-2, and Gy 3-7, have embedded clusters of early-type stars and their associated nebulae were found to be photoionized. The IRAS sources in L1455, L1473, L1165 and Gy 4-1 with near-IR reflectio n nebulae were found to be Class I young stellar objects with associat ed molecular outflows. The results for each region is discussed in det ail. (C) 1997 American Astronomical Society.