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Title: A modern search for Wolf-Rayet stars in the Magellanic Clouds: First results

Over the years, directed surveys and incidental spectroscopy have identified 12 Wolf-Rayet (WR) stars in the Small Magellanic Cloud (SMC) and 139 in the Large Magellanic Cloud (LMC), numbers which are often described as 'essentially complete'. Yet, new WRs are discovered in the LMC almost yearly. We have therefore initiated a new survey of both Magellanic Clouds using the same interference-filter imaging technique previously applied to M31 and M33. We report on our first observing season, in which we have successfully surveyed ∼15% of our intended area of the SMC and LMC. Spectroscopy has confirmed nine newly found WRs in the LMC (a 6% increase), including one of WO-type, only the third known in that galaxy and the second to be discovered recently. The other eight are WN3 stars that include an absorption component. In two, the absorption is likely from an O-type companion, but the other six are quite unusual. Five would be classified naively as 'WN3+O3 V', but such a pairing is unlikely given the rarity of O3 stars, the short duration of this phase (which is incommensurate with the evolution of a companion to a WN star), and because these stars are considerably fainter than O3 Vmore » stars. The sixth star may also fall into this category. CMFGEN modeling suggests these stars are hot, bolometrically luminous, and N-rich like other WN3 stars, but lack the strong winds that characterize WNs. Finally, we discuss two rare Of?p stars and four Of supergiants we found, and propose that the B[e] star HD 38489 may have a WN companion.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001 (United States)
  2. Las Campanas Observatory, Carnegie Observatories, Casilla 601 La Serena (Chile)
  3. Department of Physics and Astronomy and Pittsburgh Particle Physics, Astrophysics, and Cosmology Center (PITT PACC), University of Pittsburgh, Pittsburgh, PA 15260 (United States)
Publication Date:
OSTI Identifier:
22356644
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 788; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; BOLOMETERS; INTERFERENCE; MAGELLANIC CLOUDS; SEASONS; SIMULATION; SPECTROSCOPY; STAR EVOLUTION; WOLF-RAYET STARS