NGC 4102

NGC 4102 is a spiral galaxy in the constellation Ursa Major, classified as an intermediate barred type. Its core hosts a starburst region roughly 1,000 light-years across, containing about 3 billion solar masses.

A hydrogen outflow extends northwest from the nucleus up to 6.3 kiloparsecs. The galaxy’s nucleus is almost certainly an active galactic nucleus (AGN), specifically a Type-2 LINER, likely obscured by dust or powered by inefficient accretion onto a supermassive black hole. It emits X-rays with a spectrum similar to a Seyfert 2 galaxy.

Discovered by William Herschel on April 12, 1789, NGC 4102 has an apparent visual magnitude of 11.2 and is visible in a small telescope. J. L. E. Dreyer described it as bright, fairly small, round, with a brighter middle and bright nucleus.

It lies about 60 million light-years away, receding at 837 km/s, and belongs to the Ursa Major group of galaxies. Its morphological class is SABab or SAB(s)b?, indicating a small bar-like feature, no inner ring, and moderately tight spiral arms. The galactic plane is inclined relative to Earth’s line of sight.

One supernova has been observed in NGC 4102: SN 1975E, discovered on May 7, 1975, by Yvonne Dunlap and Justus R. Dunlap, with an unknown type and a magnitude of 16.7.