* Astronomy

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

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).

Read more  (125kb, PDF)


Position (J2000):     R.A. 16 04 55.22033  |  Dec. -51° 57' 12.7061''