observations of the LMC compact H II region N 11A^*

¹ DEMIRM, Observatoire de Paris, 61 avenue de l'Observatoire, 75014 Paris, France
² Cornell University, Astronomy Department, 106 Space Sciences Bldg., Ithaca, NY 14853, USA
³ Observatoire de Marseille, 2 place Le Verrier, 13248 Marseille Cedex 4, France
⁴ Space Telescope European Coordinating Facility, European Southern Observatory, Karl-Schwarzschild-Strasse-2, 85748 Garching bei München, Germany
⁵ Observatoire Midi-Pyrénées, 14 avenue E. Belin, 31400 Toulouse, France
⁶ Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany

Corresponding author: M. Heydari-Malayeri, heydari@obspm.fr

Received: 13 March 2001
Accepted: 28 March 2001

Abstract

We present a study of the LMC compact H ii region N 11A using Hubble Space Telescope imaging observations which resolve N 11A and reveal its unknown nebular and stellar features. The presence of a sharp ionization front extending over more than 4'' (1 pc) and fine structure filaments as well as larger loops indicate an environment typical of massive star formation regions, in agreement with high [O iii]/Hβ line ratios. N 11A is a young region, as deduced from its morphology, reddening, and especially high local concentration of dust, as indicated by the Balmer decrement map. Our observations also reveal a cluster of stars lying towards the central part of N 11A. Five of the stars are packed in an area less than 2'' (0.5 pc), with the most luminous one being a mid O type star. N 11A appears to be the most evolved compact H ii region in the Magellanic Clouds so far studied.