S0 galaxy

S0 galaxies are an intermediate type between elliptical and spiral galaxies. They possess a bright nucleus surrounded by a smooth bulge and a faint outer envelope, lacking the distinct spiral arms seen in spiral galaxies. Some S0 galaxies may exhibit faint arm-like structures or dust lanes. These galaxies are generally thin, with statistical studies indicating intrinsic ratios of minor to major axes between 0.1 and 0.3. While they share some characteristics with ellipticals, their structure more closely resembles that of spiral galaxies. S0 galaxies represent about 1-2% of all galaxies and can sometimes be difficult to classify due to peculiar features.1