Thackeray’s Globules in IC 2944

Floating serenely against the colourful, epic backdrop of IC 2944 (The Running Chicken Nebula) in Centaurus are Thackeray’s globules, named after the British astronomer who first described them in this object in 1950. Globules of this type are more generally known as Bok globules after Bart Bok and Edith Reilly who published a two author paper on them in 1947 [Bok, B.J. & Reilly, E.F. (1947). Small Dark Nebulae. Astrophysical journal, 105, 255-257]. On this basis, perhaps they should be more correctly termed Bok-Reilly globules. Their paper described these dark clouds as regions that were undergoing gravitational collapse to form new stars and star clusters.

Bok-Reilly globules are small isolated dark interstellar clouds of very cold gas and dust that are sufficiently thick to be nearly totally opaque to visible light, and although star formation within their interiors was hypothesised by Bok and Reilly, it has only been through relatively recent use of infrared, submillimeter, and millimeter imaging techniques that this has been verified.

This deep image of IC 2944 represents almost 25 hrs of total exposure using hydrogen alpha, OIII and SII filters and reveals lots of fine scale structure in the heart of the nebula behind the tiny globules. Also captured in this image is the very cute - but unrelated to IC 2944 - planetary nebula PK294-0.1 shown in the top left.

This is SII-H-a-O111 narrow-band image with RGB stars with 24.6 hrs total integration, shot in Nov/Dec 2023 and Jan 2024