RCW 58

RCW58, an E type nebula, is a Wolf Rayert Bubble formed by the ejecta from WR 40, the central star in the image.  These three dimensional bubbles appear as a ring in two dimensions, as seen in this image and represent the stellar ejecta contained in a wind blown bubble.  The are several similar WR ring nebulae are known including: MI-67, RCW104, RCW78, NGC3199, NGC6888.
 

H alpha and OIII emissions from eight of the most well defined Wolf Rayet ring nebulae in the Galaxy reveal that in many cases the outermost edge of the OIII emission leads the H alpha emission. This suggests that these offsets, when present, are due to the shock from the Wolf Rayet bubble expanding into the circumstellar envelope.

To see the Ha version of this object, click here.