Triangulum Galaxy
| Triangulum Galaxy | |
|---|---|
Galaxy Messier 33 in Triangulum (the Triangulum Galaxy) | |
| Observation data (J2000 epoch) | |
| Pronunciation | /traɪˈæŋɡjʊləm/ |
| Constellation | Triangulum |
| Right ascension | 01h 33m 50.02s |
| Declination | +30° 39′ 36.7″ |
| Redshift | -0.000607 ± 0.000010 |
| Heliocentric radial velocity | -179 ± 3 km/s |
| Galactocentric velocity | -44 ± 6 km/s |
| Distance | 970 kpc (3.2 Mly) |
| Apparent magnitude (V) | 5.72 |
| Characteristics | |
| Type | SA(s)cd |
| Mass | 5×1010 M☉ |
| Number of stars | 40 billion (4×1010) |
| Size | 18.74 kpc (61,120 ly) (diameter; 25.0 mag/arcsec2 B-band isophote) |
| Apparent size (V) | 70.8 × 41.7 arcminutes |
| Other designations | |
| IRAS 01310+3024, NGC 598, UGC 1117, MCG +05-04-069, PGC 5818, CGCG 502-110 | |
The Triangulum Galaxy is a spiral galaxy 2.73 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. With the D25 isophotal diameter of 18.74 kiloparsecs (61,100 light-years), the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way.
The galaxy is the second-smallest spiral galaxy in the Local Group after the Large Magellanic Cloud, which is a Magellanic-type spiral galaxy. It is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities, and proximity to one another in the night sky. It also has an H II nucleus.