* Astronomy

Title: New Results for the Open Cluster Bica 6 and its Associated Planetary Nebula Abell 8
Authors: David G. Turner, Joanne M. Rosvick, David D. Balam, Arne A. Henden, Daniel J. Majaess, David J. Lane

The likely membership of the planetary nebula Abell 8 (PN G167.0--00.9) in the open cluster Bica 6 is confirmed by CCD spectra, UBV(RI)c photometry, and radial velocities for luminous cluster stars. The reddening, estimated distance, and radial velocity of the planetary nebula agree with parameters derived for Bica 6 of E(B-V)=0.42, d=1.60±0.11 kpc, and Vr=57±1 km/s, with a cluster age of 1 Gyr, a diagnostic blue hook, and a few blue stragglers, including a peculiar B1 Vnn star (HDE 277593) that may be a post-AGB star. The results identify Bica 6 as a potential calibrator of the planetary nebula distance scale. The central star of the planetary nebula has a reddening of E(B-V)=0.49±0.02, with a possible circumnebular excess, and an estimated luminosity of Mv=+7.44±0.16. It is also an optical double in 2MASS images, with a likely progenitor according to evolutionary considerations being a late B-type dwarf of ~2.3 Msun.

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