March 22, 2023

Stunning Observation of a Dark Nebula

Credit: NASA, ESA, and R. Sahai (Jet Propulsion Laboratory); Processing: Gladys Kober (NASA/Catholic University of America).
This sensational image catches a small region on the edge of the inky Coalsack Nebula, or Caldwell 99. Caldwell 99 is a dark nebula– a dense cloud of interstellar dust that completely shuts out visible wavelengths of light from things behind it. The object at the center of the image is a (much smaller) protoplanetary nebula. The protoplanetary nebula stage is a late phase in the life of a star in which it has actually ejected a shell of hydrogen gas and is rapidly warming up. This phase only lasts for a couple of thousand years prior to the protoplanetary nebulas central star reaches roughly 30,000 Kelvin. At this point, the main star is producing enough energy to make its surrounding shell of gas radiance, becoming whats referred to as a planetary nebula.
Caldwell 99 is a very popular object in the southern night sky. On a clear night, it can be spotted quickly with the naked eye as a dark patch, space of stars, next to the Southern Cross in the constellation Crux.
Caldwell 99 is situated 600 light-years from Earth and is about 100 light-years throughout.

December 27, 2021