Deep Optical Images of the Ejecta Nebula Around the Wolf-Rayet Star WR 8 (HD 62910)

Abstract

We report the results of deep H$\alpha$ and [O III] images of the bright WN6/WC4 Wolf-Rayet star WR~8 (HD~62910). These data show considerably more surrounding nebulosity than seen in prior imaging. The brighter portions of the nebula span $\simeq6'$ in diameter and exhibit considerable fine-scale structure including numerous emission clumps and bright head-tail like features presumably due to the effects of the WR star's stellar winds. Due to the overlap of a relatively bright band of unrelated foreground diffuse interstellar H$\alpha$ emission, WR~8's nebula is best viewed via its [O III] emission. A faint $9' \times 13'$ diffuse outer nebulosity is detected surrounding the nebula's main ring of emission. Comparison of the nebula's optical structure with that seen in WISE 22 $\mu$m data shows a similarly clumpy structure but in a better defined emission shell of thermal continuum from dust. The infrared shell is coincident with the nebula's southern [O III] emissions but is mainly seen in the fainter outer portions of the northern [O III] emission clumps. It is this greater radial distance of dust emission in the nebula's northern areas that leads to a striking off-center position of the WR star in the IR shell.