This oddly shaped cloud of dusty gas is shaped by the winds and radiation from nearby stars.

Stars are born not brilliant but obscured, cocooned in piles of dust and gas called Bok globules. Astronomers have worked for the past century to understand how infant stars emerge from these cocoons. This image, from the Dark Energy Camera (DECam) on the Víctor M. Blanco 4-meter Telescope at Cerro Tololo Inter-American Observatory in Chile, helps shed light on that process.

DECam captures one of these globules, named Cometary Globule 4 ("cometary" comes from its tail-like appearance), which appears in the image as a giant, outstretched hand. CG 4 is 1,300 light-years away in the southern constellation Puppis.

Cometary Globule
The cloudy, ominous structure shown here is cometary globule (CG) 4. CG 4 is one of many cometary globules present within the Milky Way. (The edge-on spiral galaxy ESO 257-19 only appears to be next to the globule — it's in fact some 100 million years behind it from our perspective.)
CTIO / NOIRLab / DOE / NSF / AURA; Image processing: T.A. Rector / D. de Martin / M. Zamani

The sensitivity of DECam combined with its hydrogen-alpha filter reveals a faint reddish glow in the core and rim of CG4, which comes from ionized hydrogen. Intense radiation from nearby massive stars — which clear their dusty cocoons more quickly than low-mass stars — has stripped the electrons from these atoms. This ionized gas looks like it's evaporating off CG 4 like mists off a lake in the summer dawn. (See especially the addition of hydrogen-alpha data just after 0:45 in the video below.)

Even as nearby stars (two of which are shown in the inset below) rip away gas and dust from CG 4, the globule still has plenty of dusty gas to form additional new stars, which will emerge in due time.

Cometary Globule close-ups
This excerpt shows a close-up of CG 4 seemingly about to devour the edge-on spiral galaxy ESO 257-19 (PGC 21338). But in reality, this galaxy is more than a hundred million light-years beyond CG 4 and only appears to be close because of a chance alignment. Near the head of the cometary globule are two young stellar objects (YSOs). YSOs are stars in their early stage of evolution, before they become main-sequence stars, that often exhibit characteristics such as jets, bipolar outflows, protoplanetary discs, and other indicators of a new star being born.
CTIO / NOIRLab / DOE / NSF / AURA; Image processing: T.A. Rector / D. de Martin / M. Zamani

The cometary globule is one of dozens in the larger Gum Nebula, all of which have "tails" that point away from the center of the nebula. There, the stellar corpse known as the Vela pulsar sits at the center of the Vela supernova remnant. The massive star that preceded the pulsar may have sent out strong winds of particles and ultraviolet photons that have shaped the surrounding region.

Read more from NSF's NOIRLab's press release.

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Comments


Image of John Schnupp

John Schnupp

May 18, 2024 at 11:35 am

Every time I see an image of this object I can't help but wonder if it was the inspiration for the Doomsday Machine in Star Trek. Fascinating. Can't post pictures but here is a link https://www.albinokraken.com/tag/doomsday-machine/

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Image of Andrew James

Andrew James

May 18, 2024 at 6:57 pm

I think it looks like a sandworm in Frank Herbert's book Dune. I also feel sorry for the galaxy, because it looks like it's about to be eaten. I don't usually get emotion when looking at images like this one, but I did here.
DECam is just amazing, especially with the new discovery of so many new planetary nebulae. Reader can access images using the 'Legacy Survey Sky Browser' https://decaps.legacysurvey.org/viewer . [Example of planetary nebula is obscure Hen 2-120 in Circinus. Just Remarkable!]

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Image of AB

AB

May 21, 2024 at 11:01 pm

Space whale! Chomp!

"Click to accept marketing cookies and enable this content"...?
That's new...
And disappointing.

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Image of Andrew James

Andrew James

May 22, 2024 at 5:51 pm

Agreed.

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