M96 - NGC 3368

Messier 96 (NGC 3368) is a spiral galaxy located approximately 31 million light-years from Earth in the constellation Leo. It was discovered by Pierre Mechain in 1781 and is the brightest member and namesake of the Leo I Group (M96 Group) of galaxies. M96 is classified as an SAB(rs)ab galaxy, meaning it has a weak or intermediate bar and moderately tightly wound spiral arms. The galaxy has a visual magnitude of about 9.2 and spans approximately 100,000 light-years in diameter. One of M96's most notable characteristics is its markedly asymmetric appearance. The spiral arms are displaced relative to the nucleus, and the dust lanes and HII regions are unevenly distributed around the disk. This asymmetry is likely the result of gravitational interactions with other members of the Leo I Group. The galaxy is seen at a moderate inclination and displays a bright, extended nucleus surrounded by a complex pattern of dust lanes and star-forming regions. M96 has a mildly active LINER-type nucleus. The galaxy has been extensively studied as a distance indicator, with Hubble Space Telescope observations identifying Cepheid variable stars that have provided one of the most reliable extragalactic distance measurements, important for calibrating the Hubble constant. M96 also contains a population of planetary nebulae that have been used for independent distance estimates. In amateur telescopes, M96 appears as a bright, oval patch of light with a pronounced central brightening. It is the most visually impressive of the Leo I Group galaxies for visual observers. An 8-inch telescope can show the overall elongation and central concentration, while larger instruments may hint at the dust lane asymmetries.

M96 spans approximately 100,000 light-years in diameter and lies about 31 million light-years from Earth as the brightest galaxy in the Leo I Group.