New Evidence Supporting Membership for TW Nor in Lyngå 6 and the Centaurus Spiral Arm
Abstract
The putative association between the 10{.\!\!^{ d}}8 classical Cepheid TW Nor and the open cluster Lyngå 6 has generated considerable debate in the literature. New JHKs photometry in tandem with existing radial velocities for Lyngå 6 stars implies cluster membership for TW Nor and establishes the variable as a high-weight calibrator for classical Cepheid relations. Fundamental mean parameters determined for Lyngå 6 are: d = 1.91 ± 0.10 kpc, E(J - H) = 0.38 ± 0.02, and log τ = 7.9 ± 0.1. The Benedict et al./Turner 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/Lyngå 6 lie beyond the Sagittarius-Carina spiral arm and occupy the Centaurus arm, along with innumerable young Cepheids and clusters (e.g., VW Cen and VVV CL070).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 2011
- DOI:
- arXiv:
- arXiv:1110.0830
- Bibcode:
- 2011ApJ...741L..27M
- Keywords:
-
- dust;
- extinction;
- Hertzsprung-Russell and C-M diagrams;
- infrared: stars;
- open clusters and associations: individual: Lynga 6;
- stars: distances;
- stars: variables: Cepheids;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for Publication (ApJ Letters)