Abell 12

Abell 12, also known as PK 198+04 1, is a planetary nebula located in the constellation Orion. It is notable for its faintness and its location in front of a bright star, HD 35619, which is unrelated to the nebula. The star, a magnitude 10.6 yellow giant, appears to sit at the center of the nebula in images, creating a striking visual effect.

The nebula itself is relatively old and evolved, resulting in a diffuse and low-surface brightness. Its true distance is uncertain, making estimations of its physical size and luminosity challenging. However, spectral analysis and other observations indicate it's a typical planetary nebula in its later stages of development.

The unrelated foreground star complicates the study of Abell 12. Its brightness overwhelms the fainter light emitted by the nebula itself, making it difficult to analyze the nebula's composition and structure in detail. Specialized techniques are required to subtract the star's light and reveal the faint nebulosity.

Abell 12 is of interest to astronomers studying the evolution of planetary nebulae and the late stages of stellar evolution. The unusual configuration of the nebula with the foreground star also makes it a popular target for astrophotography.