M90 - NGC 4569

Messier 90 (NGC 4569) is a spiral galaxy located approximately 60 million light-years from Earth in the constellation Virgo, though some distance estimates place it slightly closer. It was discovered by Charles Messier in 1781 and is one of the larger spiral galaxies in the Virgo Cluster. M90 is classified as an SAB(rs)ab spiral galaxy and spans approximately 120,000 light-years in diameter. Like M86, M90 has a notable blueshift, approaching the Milky Way at about 235 kilometers per second, indicating it is moving rapidly through the Virgo Cluster in our direction. M90 is a fascinating case study in the process of galaxy evolution driven by environment. As it moves at high speed through the hot intergalactic medium of the Virgo Cluster, ram pressure stripping is actively removing gas from its disk. Radio and ultraviolet observations have revealed that M90 has already lost a substantial fraction of its hydrogen gas, and the remaining gas is concentrated in the inner regions of the disk. The outer spiral arms are largely stripped of star-forming material and appear smooth and red, while the inner arms still show blue star-forming regions. M90 is essentially transforming from a blue, gas-rich spiral into a red, anemic spiral galaxy in real time, providing astronomers with a snapshot of this important evolutionary pathway. The galaxy has a visual magnitude of about 9.5 and a low-luminosity active galactic nucleus. In amateur telescopes, M90 appears as a large, elongated, diffuse glow with a bright central region. Its size and brightness make it one of the more prominent Virgo Cluster spirals, though its low surface brightness arms are difficult to see visually.

M90 spans approximately 120,000 light-years in diameter and lies about 60 million light-years from Earth, approaching us at about 235 km/s.