Abell 31(Sh2-290) – The Ghostly Face

Abell 31, also known as Sh2-290, is one of the largest and oldest planetary nebulae known, located about 2,000 light-years away in the constellation Cancer. Spanning roughly 10 light-years in diameter, it represents the final stages of a star's life where its outer layers have drifted into space, leaving behind a hot white dwarf at its core.

 The nebula is most famous for its striking "bow shock" appearance on its southern edge. This happens because Abell 31 is moving rapidly through the interstellar medium; as it plows through the surrounding gas, the leading-edge compresses and glows more intensely. This gives the nebula a distinct, slightly lopsided shape rather than a perfect sphere.

 In the core of this egg-shaped planetary nebula is a ghostly face on the right-hand side as if it’s looking out into the expanse of space.

 Because of its ancient age—estimated at over 130,000 years—the nebula has a very low surface brightness. It is notoriously difficult to observe visually through a telescope and is primarily a favorite for deep-sky astrophotographers. Long-exposure images reveal a beautiful contrast between the red hydrogen-alpha emissions and the blue-green glow of ionized oxygen.

Equipment: Planewave 17”CDK and Sbig 16803 camera, Imaged at SWO in New Mexico

Taken in LRGBHAO3S2

Image Processing and data collection: Mark Hanson

Enjoy, Mark