NGC 634

NGC 634 is a spiral galaxy located in the constellation Triangulum. It is estimated to be approximately 250 million light-years away from Earth.

NGC 634 is classified as a type Sa galaxy, indicating a spiral galaxy with tightly wound arms and a large, bright central bulge. It exhibits a relatively smooth disk with little star formation activity compared to other spiral galaxy types like Sc.

This galaxy is notable for being the host galaxy of the Type Ia supernova SN 2008a. Type Ia supernovae are particularly important in cosmology as they serve as "standard candles," allowing astronomers to measure cosmic distances. The supernova event in NGC 634 was used to refine distance measurements to the galaxy.

NGC 634 was discovered on October 28, 1865, by French astronomer Édouard Stephan. It is included in the New General Catalogue of Nebulae and Clusters of Stars (NGC), a widely used catalogue of deep-sky objects.

The galaxy is also catalogued as UGC 1149, MCG +06-04-048, IRAS 01354+3507, and PGC 6083. Its coordinates are right ascension 01h 38m 18.7s and declination +35° 21' 53".

Further research on NGC 634, including spectroscopic and photometric observations, continues to contribute to our understanding of galaxy evolution, supernovae, and the large-scale structure of the universe.