Affiliation:
1. School of Physics, University of New South Wales, Sydney, NSW 2052, Australia
2. Centre of Excellence for Astrophysics in Three Dimensions (ASTRO-3D), Australia
Abstract
ABSTRACT
We report the discovery of the only very nitrogen-enhanced metal-poor star known in a Galactic globular cluster. This star, in the very metal-poor cluster ESO280−SC06 , has $[\textrm{N}/\textrm{Fe}]\, \gt +2.5$, while the other stars in the cluster show no obvious enhancement in nitrogen. Around 80 NEMP stars are known in the field, and their abundance patterns are believed to reflect mass transfer from a binary companion in the asymptotic giant branch phase. The dense environment of globular clusters is detrimental to the long term survival of binary systems, resulting in a low observed binary fraction among red giants and the near absence of NEMP stars. We also identify the first known horizontal branch members of ESO280−SC06 , which allow for a much better constraint on its distance. We calculate an updated orbit for the cluster based on our revised distance of 20.6 ± 0.5 kpc, and find no significant change to its orbital properties.
Funder
Anglo-Australian Telescope
Australian Research Council
Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions
Publisher
Oxford University Press (OUP)
Subject
Space and Planetary Science,Astronomy and Astrophysics
Cited by
10 articles.
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