A small, dense cloud of gas and dust called CB 130-3 occupies the center of this image, taken by NASA/ESA’s Hubble Space Telescope. CB 130-3 is an object known as a dense core, a compact cluster of gas and dust. This particular dense core is located in the constellation Serpent and appears to pulsate in a field of background stars.

Dense cores such as CB 130-3 are the birthplace of stars and are of particular interest to astronomers. During the collapse of these cores, enough mass can accumulate in one place to reach the temperatures and densities necessary to ignite the hydrogen fusion, which means the birth of a new star. While not apparent in this image, the swaying compact object on the verge of becoming a star is buried deep within CB 130-3.

Astronomers used Hubble’s wide-angle camera 3 to better understand the environment surrounding this young star. As this picture shows, the density of CB 130-3 is not constant; While the outer edges of the cloud are made up of only thin clusters, the CB 130-3 completely suppresses background light in its core.

The gas and dust that make up CB 130-3 affect not only the brightness but also the apparent color of the background stars; stars in the center of the cloud appear redder than their counterparts at the edges of this image. The astronomers used Hubble to measure this reddening effect and plot the density of CB 130-3, providing information about the interior structure of this stellar nursery.