NGC 281

Lore & Background

Edward Emerson Barnard discovered the nebula in August 1883, describing it as 'a large faint nebula, very diffuse'. The multiple star B 1 (β 1) was later discovered by S. W. Burnham; its bright component is the highly luminous O6 spectral class star HD 5005 (HIP 4121). This quintuple system consists of an 8th-magnitude primary with four companions at separations between 1.4 and 15.7 arcseconds, and no appreciable change has been observed since the first measures in 1875.

The nebula region is visible in amateur telescopes from dark sky locations. In his book Deep Sky Wonders, Walter Scott Houston described its appearance in small telescopes: 'There was a faint glow in the immediate vicinity of the multiple star, with an occasional impression of a much larger nebulosity...Its surface brightness was much less than that of M33 in Triangulum or NGC 205, the distant companion of the Andromeda galaxy.'

Reader's Guide

NGC 281 holds significance as a bright emission nebula within the Perseus Spiral Arm of the Milky Way, notable for its association with the open cluster IC 1590, Bok globules, and the multiple star B 1. Its colloquial name, the Pacman Nebula, derives from its resemblance to the video game character, adding to its recognition among amateur astronomers. The nebula's distance, estimated at 9200 light-years from 2014 radio parallax measurements of water masers, provides a modern anchor for studies of this H II region. Discovered by Edward Emerson Barnard in 1883, the nebula was described as faint and diffuse, while the multiple star system B 1, discovered by S. W. Burnham, has shown no change since 1875, offering a stable reference point. Walter Scott Houston's observations in Deep Sky Wonders note its low surface brightness compared to M33 and NGC 205, guiding observers on what to expect in small telescopes. The nebula's visibility from dark sky locations makes it accessible to amateur astronomers, and its inclusion in astronomical catalogs (NGC, IC, Sh2) underscores its enduring interest.

Did You Know?

• NGC 281 is colloquially called the Pacman Nebula for its resemblance to the video game character.
• The nebula was discovered by Edward Emerson Barnard in August 1883, who described it as 'a large faint nebula, very diffuse'.
• A 2014 distance estimate using radio parallaxes of water masers at 22 GHz places NGC 281 at 9200 light-years.