Thor’s Helmet: An Unguided Narrowband-enhanced LRGB Image from Urban Halifax

Hal Heaton
Location of photo
Burke-Gaffney Observatory, St. Mary's University, Halifax, NS
Date/Time of photo
Several nights from 7 Dec 2016 to 3 Apr 2018
Planewave Model CDK24 (Corrected Dall-Kirkham) reflector, aperture 0.61 meters (24 inch), at f/6.5. Apogee Aspen CG16M CCD camera binned 2 x 2 (2048 x 2048 pixels). Astrodon Gen II Series-E filters
Thor's Helmet is a wind-blown bubble around the Wolf-Rayet star WR7 that is unique in its morphology. The central bubble with its fine filaments principally contains interstellar material that has been swept up by the fast wind streaming away from the central star. Interactions with a nearby molecular cloud mask the outer regions of the bubble to the southeast (north is up, east is to the left), and additional interactions with the surroundings are apparent in the reddish-colored ionization fronts on the outer edges of the spiral-like features emanating from near the surface of the bubble. At an adopted distance of 11,960 lys, this cropped image is 78.7 x 80.1 lys in extent; the central bubble spans roughly 16 lys. Recent research based on the high 26Al/27Al and low 60Fe/56Fe ratios found at the time of solar system formation suggests that the Sun may have arisen from triggered star formation in the swept-up shell of an ancient Wolf Rayet bubble.

One thought on “Thor’s Helmet: An Unguided Narrowband-enhanced LRGB Image from Urban Halifax

  1. Hal HeatonHal Heaton Post author

    A correction: Since I rotated the image by 90 degrees relative to its acquired orientation, north is to the left and east is down.

All comments must follow the Sky & Telescope Terms of Use and will be moderated prior to posting. Please be civil in your comments. Sky & Telescope reserves the right to use the comments we receive, in whole or in part, and to use the commenter’s username, in any medium. See also the Terms of Use and Privacy Policy.


This site uses Akismet to reduce spam. Learn how your comment data is processed.