NGC 281 - Pacman Nebula

Object Name: NGC 281, IC 0011, Pacman Nebula, IC 1590

Object Type: Nebula, Star Cluster, Open Cluster, HII Region


NGC 281

Image Credit & Copyright: Wido Oerlemans - X-ray: Chandra, Infrared: Spitzer 2021 November 19

NGC 281 was discovered in 1883, located in the northern constellation of Cassiopeia, as part of the Milky Way Galaxy’s Perseus spiral arm, and accepts a resemblance to the iconic character from the 1980s video game, Pac-Man. Hence, astronomers have named it the "Pacman Nebula." At its core lies the open cluster of stars known as IC 1590, discernible even in modest telescopes accompanied by faint nebulosity, so a more extended observation period is required to study it.

There are vivid blue stars at its center, a dark lane reaching a "mouth," and numerous dark spots spread across its spectrum. Its natural hue is red, because of the ionization of hydrogen gas by the intense ultraviolet radiation emitted by the nascent, hot stars within.

Functioning as a hub of active star formation within our galaxy, the Pacman Nebula represents an area where the interstellar medium coalesces into denser clouds. These clouds experience ionization by the energetic radiation from newly formed stars, a phenomenon astronomers refer to as HII Regions. The youthful stars gathered in an Open Cluster labeled IC 1590, have emerged within the past few million years. The hydrogen gas, interacting with these young stars, emits the red glow observed in the nebula. The dark lanes indicate regions of concentrated dust and cool gas, predominantly molecular hydrogen, likely to foster future stellar births as their density increases.

Sprinkled across the nebula are "Bok globules," regions of the coldest and densest gas and dust. These serve as incubators for new stars, shielding them from the disruptive forces of neighboring hot, young stars. However, some globules may succumb to disruption by the intense radiation and winds emitted by these stellar neighbors before the star formation within their cores. This appears to be the future of the most identified globules nestled at the core of NGC 281.