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A hidden population of Wolf-Rayet stars in the massive galactic cluster Westerlund 1

J. Simon Clark·Ignacio Negueruela
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Abstract

We report the discovery of a hitherto undetected population of Wolf-Rayet stars in the young galactic open cluster Westerlund 1. Optical spectroscopy of the cluster identified 11 such objects; provisional classification suggests that 6 are nitrogen rich (WN) and 5 carbon rich (WC). Including the previously identified Blue, Yellow and Red Super- & Hypergiants, Westerlund 1 clearly has a very rich population of massive post-Main Sequence objects. To date, the post-MS population of Westerlund 1 is significantly larger than that of any other galactic young open cluster - with the possible exception of the Arches - implying that it is potentially amongst the most massive young clusters yet identified in the Local Group.

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J. Simon Clark, Ignacio Negueruela. 2002-11-12. A hidden population of Wolf-Rayet stars in the massive galactic cluster Westerlund 1. https://doi.org/10.1051/0004-6361%3A20021623

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