A nebula that extends its hand into space

The Gum Nebula is an emission nebula nearly 1400 light-years away. It is house to an object generally known as “God’s Hand” among the many devoted. The remainder of us name it CG 4.

Many objects in space tackle fascinating, ethereal shapes straight out of somebody’s psychedelic fantasy. CG4 is unquestionably ethereal and extraordinary, but it surely’s additionally a bit of extra prosaic. It seems like a hand extending into space.

The Darkish Vitality Digital camera (DECam) on the NSF’s Víctor M. Blanco 4-meter Telescope captured the picture. DECam’s major job is to survey tons of of hundreds of thousands of galaxies in its examine of darkish vitality. However it’s additionally a general-purpose instrument used for different scientific endeavors.

CG 4 is known as a cometary globule due to its look. However it’s truly a star-forming area. It has a head that is about 1.5 light-years in diameter and a tail that is about 8 light-years lengthy. The top is dense and opaque and is lit up by a close-by star. The globule is surrounded by a diffuse pink glow, emissions from ionized hydrogen.

There are many cometary globules within the Milky Way. They seem to be a sub-class of objects referred to as Bok globules, after astronomer Bart Bok, who found them. Each kinds of globules are darkish nebulae, molecular clouds so dense they block optical mild. Astronomers aren’t completely sure how cometary globules get their form.

However they do know what’s occurring to them.

The pink glow surrounding CG 4 is ionized hydrogen lit up by radiation from close by sizzling, massive stars. That very same radiation is eroding CG 4 away. Because the globule is denser than its environment, it is resisting diffusion. It nonetheless comprises sufficient gasoline and dust to type a number of new stars about as huge because the sun.

Though there are various of those globules within the Milky Way, the vast majority of them are within the Gum Nebula. Scientists know of 31 different globules within the nebula. This one’s referred to as CG 4 (Cometary Globule 4) as a result of they’re all numbered.

The Gum Nebula is probably going the remnant of an enormous supernova explosion, and that might be the explanation the globules have their distinctive form. They might have initially been spherical nebula just like the Ring Nebula. However a robust supernova explosion about 1 million years in the past stretched them into their lengthy, comet-like types.

Astronomers additionally counsel one more reason for his or her form. Close by sizzling, huge stars exert radiation strain on the globules, and their stellar wind additionally slams into them. Within the Gum Nebula, their tails level away from the Vela Supernova Remnant and the pulsar that sits in its heart. Because the Vela Pulsar is a spinning neutron star, it is potential that its winds and radiation pressure are shaping CG 4.