NGC 3021

NGC 3021 is a spiral galaxy located approximately 140 million light-years away in the constellation Leo Minor. It is classified as a Sc galaxy, indicating a spiral galaxy with loosely wound spiral arms and a relatively small central bulge.

NGC 3021 is of particular interest to astronomers because it was the host galaxy for supernova SN 1995al, a Type Ia supernova. Type Ia supernovae are crucial "standard candles" used to measure distances in the universe, as they have a consistent peak brightness. The study of SN 1995al in NGC 3021 helped refine our understanding of these important cosmological tools and further constrain the Hubble constant.

The galaxy exhibits active star formation within its spiral arms, which are dotted with HII regions – clouds of ionized hydrogen gas that glow brightly due to the presence of young, hot stars. These regions are indicators of ongoing stellar birth.

NGC 3021 is relatively isolated, not belonging to a large galaxy cluster. Its isolation allows for clearer observations of its internal structure and properties, undisturbed by the gravitational influence of nearby galaxies.