NGC 2139 is a barred spiral galaxy in the constellation of Lepus. It was discovered on November 17, 1784, by the German-English astronomer William Herschel. The galaxy is located at a distance of from the Sun and is receding with a radial velocity of 1,836 km/s.
The overall form of this galaxy is irregular with spiral arms and the appearance of tidal features, suggesting a potential recent merger event. There is no central bulge of significance. The morphological classification is SAB(rs)cd, which indicates a barred spiral galaxy (SAB) with a transitional inner ring structure (rs) and loosely wound spiral arms (cd). It is a star forming galaxy with a formation rate of ÷yr<sup>âÂÂ1</sup>. There is a plume extending to the south of the galaxy.
A luminous filament runs through the center of the galaxy, which includes a small nuclear cluster. This cluster is only old with a mass of . It is offset at a distance of 320 pc from the center of the galaxy and may come to rest there on a time scale of around 100 million years. The cluster is a source of X-ray emission.
Three supernovae have been observed in NGC 2139: