SCYON Abstract

Received on September 4 2012

High resolution elemental abundances analysis of the open cluster IC 4756

AuthorsTing, Yuan-Sen (1,2), De Silva, Gayandhi (3), Freeman, Ken (1), Parker, Stacey-Jo (4)
Affiliation(1) Research School of Astronomy & Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611, Australia
(2) Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02139, USA
(3) Australian Astronomical Observatory, PO Box 296, NSW 1710, Australia
(4) Institute of Astronomy, University of Cambridge, UK
Accepted byMonthly Notices of the Royal Astronomical Society
Contactgdesilva@aao.gov.au
URLhttp://arxiv.org/abs/1207.7076
Links IC 4756

Abstract

We present detailed elemental abundances of 12 subgiants in the open cluster IC 4756 including Na, Al, Mg, Si, Ca, Ti, Cr, Ni, Fe, Zn, Ba. We measure the cluster to have [Fe/H] = -0.01 +/- 0.10. Most of the measured star-to-star [X/H] abundance variation is below sigma < 0.03, as expected from a coeval stellar population preserving natal abundance patterns, supporting the use of elemental abundances as a probe to reconstruct dispersed clusters. We find discrepancies between Cr I and Cr II abundances as well as Ti I and Ti II abundances, where the ionized abundances are larger by about 0.2 dex. This follows other such studies which demonstrate the effects of overionization in cool stars. IC 4756 are super-solar in Mg, Si, Na, Al, but are solar in the other elements. The fact that IC 4756 is super-solar in some alpha-elements (Mg, Si) but solar in the others (Ca, Ti) suggests that the production of alpha-elements is not simply one dimensional and could be exploited for chemical tagging.