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arXiv · 1110.0830

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

Daniel J. Majaess·David G. Turner·Christian Moni Bidin·Francesco Mauro·Douglas Geisler·Wolfgang Gieren·Dante Minniti·André-Nicolas Chené·Philip Lucas·Jura Borissova·Radostn Kurtev·Istvan Dékány·Roberto K. Saito
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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: W_VI,0=(-3.37+-0.08)log(P_0)-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).

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Daniel J. Majaess, David G. Turner, Christian Moni Bidin, Francesco Mauro, Douglas Geisler, Wolfgang Gieren, Dante Minniti, André-Nicolas Chené, Philip Lucas, Jura Borissova, Radostn Kurtev, Istvan Dékány, Roberto K. Saito. 2011-10-04. New Evidence Supporting Membership for TW Nor in Lynga 6 and the Centaurus Spiral Arm. https://doi.org/10.1088/2041-8205%2F741%2F2%2Fl27

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