The Small Sagittarius Star Cloud has nurseries filled with goblins.
That sounds like an “Addams Family” plotline. But it’s the result of murky clouds of dust that block starlight from farther away. In a new image from the European Space Observatory (ESO), dense star-making regions produce haunting shadows in space in the constellation Sagittarius.
Astronomers call them dark, or absorption, nebulas. Two prominent ghoul-shaped regions in an ESO image published Sept. 12 don’t emit light, so we can’t see them directly with visible light observations. But these tightly-packed stardust clumps reveal themselves by leaving outlines against the brighter stellar population behind them. According to NASA, dark nebulas are sometimes called “holes in the sky.”
Just because these nebulas are dark doesn’t mean they’re dim: stars could be forming inside their dense clouds, but obscured from view.
The two clouds are called Barnard 92 (right) and Barnard 93 (left). They are “creating these hazy ghostlike features” against an area “so rich in stars that it is clearly visible to the naked eye during dark nights,” ESO officials wrote in the image description.
ESO’s VLT Survey Telescope (VST) at the Paranal Observatory in Chile took this image. It harnessed the 268 million pixel OmegaCAM camera to conduct the VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+), and this image comes from that work.
It’s a feast for the eyes, but also gives astronomers more information on how stars evolve in the Milky Way.