SCYON Abstract

Received on October 9 2011

New Evidence Supporting Membership for TW Nor in Lynga 6 and the Centaurus Spiral Arm

AuthorsD. Majaess (1), D. Turner (1), C. Moni Bidin (2), F. Mauro (2), D. Geisler (2), W. Gieren (2), D. Minniti (3,4,5), A-N. Chene (2,7), P. Lucas (6), J. Borissova (7), R. Kurtev (7), I. Dekany (3), and R. Saito (3)
Affiliation(1) Saint Mary's University, Halifax, Nova Scotia, Canada
(2) Universidad de Concepcion, Concepcion, Chile
(3) Pontificia Universidad Catolica de Chile, Santiago, Chile
(4) Vatican Observatory, Vatican City, Italy
(5) Princeton University, Princeton, New Jersey, USA
(6) University of Hertfordshire, Hatfield, United Kingdom
(7) Universidad de Valparaiso, Valparaiso, Chile
To appear inApJ Letters
Contactdmajaess@ap.smu.ca
URLhttp://arxiv.org/abs/1110.0830
Links Lynga 6

Abstract

The putative association between the 10.8 d classical Cepheid TW Nor and the open cluster Lynga 6 has generated considerable debate in the literature. New JHKs photometry in tandem with existing radial velocities for Lynga 6 stars imply cluster membership for TW Nor, and establish the variable as a high-weight calibrator for classical Cepheid relations. Fundamental mean parameters determined for Lynga 6 are: d=1.91+-0.10 kpc, E(J-H)=0.38+-0.02, and log(t)=7.9+-0.1. The Benedict et al.(2007)/Turner (2010) Galactic VIc Wesenheit function was revised using TW Nor's new parameters: WVI,0=(-3.37+-0.08)log(P0)-2.48+-0.08. TW Nor/Lynga 6 lie beyond the Sagittarius-Carina spiral arm and occupy the Centaurus arm, along with innumerable young Cepheids and clusters (e.g., VW Cen & VVV CL070).