New Views of the Magellanic Clouds fA U Symposium, Vol. 190, 1999 Y.-H. Chu, N.B. Suntzef], J.E. Hesser, and D.A. Bohlender, eds. The Compact HII Regions NIIA and N88A in the LMC and SMC G. Testor Observatoire de Meudon, 92195 Meudon Cedex, France C. S. Rola Institute of Astronomy, University of Cambridge, United Kingdom A. B. Whiting Physics Department, U.S. Naval Academy, Annapolis, MD 21402, USA Abstract. Several spectra have been obtained in the 3600-10000 A range, for the HII regions NIIA and N88A in the LMC and SMC, respec- tively. The spectral type of their exciting star was determined and from the emission-line intensities we have derived the gas electron density and temperature, and computed the chemical abundances of He, 0, N, Ne, S, and Ar. These abundances are then compared with the ones found for other HII regions in the Magellanic Clouds. 1. Introduction and Observations The compact HII regions N88A and NIIA, with FWHMH,B rv Z'4 and 5" respec- tively (Heydari & Testor 1985; Kurt et al. 1995), are extremely bright and their emission line strengths enable accurate derivation of their physical conditions. A series of long- and short-exposure long-slit visible and near infrared spectra with a resolution of 1.3 - 6.4 A were obtained during several runs at the ESO 1.5-m telescope. We determined the spectral types of the stars by comparing our spectra with those of the standards in Walborn & Fitzpatrick's atlas (1990). The nebular and stellar profiles of the HelA4471 line can be distinguished in our highest-resolution spectra. Physical parameters of the nebulae were determined with a five-level atom code, using the latest atomic data. The emission-line in- tensities were corrected for reddening using the Seaton law (Seaton, 1979). Three electron temperatures T e , associated with different ionization regions in the neb- ulae, were computed from the line ratios [0111] AA4363/4959+5007 (T?3), [NIl] ;\;\5755/6548+6584 and [all] ;\A3727/7319+ 7330 (T?2). The electron density n, was computed from the [SII]AA6717/6731 intensity ratio. Due to a low SIN in the [NII];\5755 line, only T?3 and T?2 were used to calculate the corresponding emissivities. 132 use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1017/S0074180900117632 Downloaded from https://www.cambridge.org/core. IP address: 54.161.69.107, on 05 Jun 2020 at 00:28:31, subject to the Cambridge Core terms of