SCYON Abstract

Received on February 1 2007

Rotation and Abundances in Ap Members of NGC 6475

AuthorsC.P. Folsom (1,2), G.A. Wade (1), S. Bagnulo (3), and J.D. Landstreet (4)
Affiliation
(1) Department of Physics, Royal Military College of Canada, P.O. Box 17000, Station "Forces", Kingston, Ontario, Canada, K7K 7B4
(2) Department of Physics, Engineering Physics & Astronomy, Queen's University, Kingston, Ontario, Canada, K7L 3N6
(3) European Southern Observatory, Casilla 19001, Santiago 19, Chile
(4) Physics & Astronomy Department, The University of Western Ontario, London, Ontario, Canada, N6A 3K7
Accepted byMonthly Notices of the Royal Astronomical Society
ContactColin.Folsom@rmc.ca
URLhttp://arxiv.org/abs/astro-ph/0612284
Links NGC 6475

Abstract

The connection between age, rotation and chemical abundance of magnetic Ap stars is poorly understood. Using open clusters, we are able to study samples of stars that are both co-eval and co-environmental. By determining rotation and chemical abundance for Ap star members of clusters with various ages, the variations of these properties as a function of age and environment can be derived. All four probable Ap star members of the open cluster NGC 6475, as well as one normal late B star, were studied using detailed spectrum synthesis of high resolution UVES-POP spectra. Probable cluster membership was confirmed for all five stars, however chemical abundance anomalies only appear to be present in spectra of three. Projected rotational velocity and chemical abundances for 21 elements ranging from C to Eu are presented for the 5 stars. In the three peculiar stars we find overabundances of Si, Cr, Mn, Fe and rare earths such as Nd, characteristic of Ap stars. The set of chemically peculiar stars show fairly homogeneous abundance tables, however notable differences exist for a few elements. There also exist appreciable differences in the v sin i, and main sequence evolutionary stage of the chemically peculiar stars. This may hint at the underlying processes giving rise to the observed abundance anomalies. With this first detailed study of chemical abundances of a complete sample of magnetic Ap/Bp stars in an open cluster, we have initiated an exploration of the environmental and evolutionary influence on chemical peculiarity.