A survey of nebulae around Galactic Wolf-Rayet stars in the southern sky, 1

Abstract

We present the second half of a charge coupled device (CCD) narrow-band imaging survey of galactic Wolf-Rayet stars located in the southern hemisphere as listed by van der Hucht et al. (1981). Images of 50 Wolf-Rayet stars were taken using a wide-field CCD and narrowband interference filters centered on H alpha and (O III) 5007 A wavelengths. The first half of the survey (Marston, Chu, & Garcia-Segura 1993, hereafter Paper I) revealed six new ring nebulae residing around Wolf-Rayet stars. Here we reveal a possible 11 new rings and the existence of multiple rings associated with two previously known nebula, RCW 118 and G2.4+1.4 and around the stars WR 16 and WR 43. Combining our results with those of Miller & Chu (1993) and Paper I, 92% of the van der Hucht catalog of Wolf-Rayet stars have now been surveyed. Of the 38 possible ring nebulae found in our surveys to date, 22 reside around WN subtype Wolf-Rayet stars, 13 around WC stars, one around a triplet of Wolf-Rayet stars and one around a WO star (WR 102). One ring exists around a WN/WC star (WR 98). A bias toward rings being observed around W-R + OB binaries is noted. Such pairings are generally bright, and the detection of a ring around them may merely be a function of their combined luminosity. Several Wolf-Rayet stars are shown to be surrounded by multiple rings (two or three) which suggests that a number of ejections of stellar material have taken place during their evolution.