CG 4 is a cometary globule located in the Gum Nebula. Its peculiar shape has earned it its unique names. It is called a "cometary globule" due to its tail resembling a comet, and specifically "Hand of God" because it looks like an outstretched arm in the cosmos.
Credit: CTIO/NOIRLab/DOE/NSF/AURA
In this new image taken by the DECam camera on the Blanco telescope in Chile, the dusty head and long tail of CG 4 resemble a mouth about to devour the galaxy ESO 257-19. This galaxy is actually more than 100 million light-years away. A
zoomable image shows the detailed head and tail of CG 4, as well as two young stars in formation.
The formation of cometary globules remains a mystery. Some astronomers believe they are shaped by the stellar winds of nearby massive stars. Others suggest they could be spherical nebulae distorted by the impact of a nearby supernova.
CG 4 might be the expanding remnants of a supernova that occurred about a million years ago. Cometary globules are not rare in the
Milky Way, but the Gum Nebula alone hosts at least 32, according to the NOIRLab of the National Science Foundation. The Gum Nebula is an emission nebula, a cloud of hot gas energized by a nearby star.
NOIRLab diagrams show the position of two young stars forming in the cometary globule.
Credit: CTIO/NOIRLab/DOE/NSF/AURA.
Image processing: T.A. Rector (University of Alaska Anchorage/NOIRLab of the NSF), D. de Martin & M. Zamani (NOIRLab of the NSF) Although the Gum Nebula is a large structure, it is very dim. Scientists used DECam's special Hydrogen-alpha filter to image CG 4. Hydrogen becomes ionized when struck by radiation from stars, allowing DECam to capture a faint red glow in the head of CG 4 and around its outer edge.
Managed by NOIRLab, DECam is a 570-megapixel camera with 74 sensors. It is installed on the Víctor M. Blanco telescope, a 13-foot (4-meter) telescope at the Cerro Tololo Inter-American Observatory on Cerro Pachon in Chile.