New objects with the B[e] phenomenon in the Large Magellanic Cloud⋆
Instituto de Ciencias Astronómicas, de la Tierra y del Espacio (ICATE), CONICET,
Casilla de Correo 49,
2 Department of Physics and Astronomy, University of North Carolina at Greensboro, Greensboro NC 27402–6170, USA
Received: 19 March 2014
Accepted: 3 June 2014
Aims. The study is aimed at discovering new objects with the B[e] phenomenon in the Large Magellanic Cloud.
Methods. We report medium-resolution optical spectroscopic observations of two newly found (ARDB 54 and NOMAD 0181−0125572) and two previously known (Hen S–59 and Hen S–137) supergiants with the B[e] phenomenon in the Large Magellanic Cloud. The observations were obtained with the GMOS spectrograph at the southern Gemini telescope.
Results. The optical spectra and the fundamental parameters of ARDB 54 and NOMAD 0181−0125572 are presented for the first time. We found that the Balmer line profiles of Hen S–59 and Hen S–137 were different from those observed in their spectra nearly 20 years ago. We suggest a higher effective temperature and luminosity for both objects. With the new fundamental parameters, the lowest luminosity for known supergiants with the B[e] phenomenon in the Magellanic Clouds is higher that previously thought (log L/L⊙ ~ 4.5 instead of 4.0). The object Hen S–59 may be a binary system based on its UV excess, variable B − V color-index and radial velocity of emission lines, and periodically variable I-band brightness.
Key words: stars: early-type / stars: emission-line, Be / supergiants / techniques: spectroscopic / Magellanic Clouds / circumstellar matter
Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovacão (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).
© ESO, 2014