SPATIALLY INTEGRATED SPECTROSCOPY OF THE GALACTIC H-II REGION M8

We present preliminary results of new long slit (7.6 arcmin) optical ( 3700-10 100 A) spatially integrated spectroscopic observations of a ce ntral portion of the galactic H II region M8, including the exciting s tar HD 164794 (O4V). With the slit of the telescope aligned N-S we ''s canned'' an area of almost-equal-to 7.6 arcmin2. We extracted the spec tra along the spatial direction, first including along with the nebula r spectrum, the spectra of the exciting stars (case 1), and then exclu ding these stellar spectra (case 2). The line fluxes for the Balmer se ries are systematically bigger (approximately 2 to 8 %) in the case wh ere the exciting stars have been excluded (case 2). The fluxes in the prominent [O III] and [S III] lines are practically the same in both c ases, while those of the [O I], [O II] and [N II] lines are smaller (a pproximately 2 to 6 %) in case 2 than in case 1. These small differenc es, if real, cause the model-assigned Effective Temperature for the ne bula be approximately 1 to 2 % cooler in case 2 with respect to case 1 and may have some consequences on analysis of giant extragalactic H 1 1 regions where the exciting stars are not resolved.