NGC 5502 (also cataloged as NGC 5503) is a spiral galaxy located in the constellation Ursa Major. It is listed in the New General Catalogue (NGC).
Observation data (J2000 epoch):
- Constellation: Ursa Major
- Right ascension: 14h 09m 33.9s
- Declination: +60° 24′ 34.3″
- Redshift: 0.02940
- Heliocentric radial velocity: 8,684 km/s
- Distance: Approximately 400 ± 28 million light-years (122.6 ± 8.6 Mpc)
- Apparent magnitude (V): 15.9
- Absolute magnitude (V): −19.5
- Type: Sa D (spiral galaxy)
- Apparent size: 0.63′ × 0.29′
- Other designations: MCG +10-20-077, PGC 50508
Observation history: NGC 5502 was discovered by Edward Swift on 9 May 1885. It was later independently observed and double-listed by his son, Lewis Swift, on 11 May 1885 as NGC 5503. The two entries were described with slightly different positional notes: Edward Swift noted the object as "between two stars, one a wide double," while Lewis Swift described it as "forms with two stars a right triangle." In the New General Catalogue, John Louis Emil Dreyer described the galaxy as "most extremely faint, very small, round, very difficult, 2 stars near." The apparent difference in recorded positions (about 2 arcminutes) is believed to have caused the duplicate listing under two NGC numbers.
Physical characteristics: Based on its recessional velocity, NGC 5502 is estimated to be approximately 400 million light-years from the Milky Way. It has a diameter of roughly 35,000 light-years. The galaxy is classified as a spiral galaxy of type Sa, indicating a relatively early-type spiral with tightly wound arms.
