The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Andromeda Galaxy and the Milky Way. It is a spiral galaxy with a diameter of about 60,000 light-years, making it about half the size of our Milky Way. M33 is notable for its high rate of star formation and numerous bright star-forming regions. Under exceptionally dark skies, it is one of the most distant objects visible to the naked eye, showcasing its significance in both professional astronomy and amateur astrophotography.
Names and Catalog numbers
– Triangulum Galaxy
– Messier 33 (M33)
– NGC 598
– UGC 1117
Position and the cosmic neighborhood
The Triangulum Galaxy is situated in the northern sky, forming part of the constellation Triangulum. It is located near the celestial equator, making it visible from both hemispheres. M33 is part of the Local Group of galaxies, which includes our Milky Way and the Andromeda Galaxy. It is positioned about 750,000 light-years from the Andromeda Galaxy, potentially making it a satellite of the larger galaxy.
Nice to Know
1. M33 has one of the highest star formation rates in the Local Group, about ten times higher than the Andromeda Galaxy.
2. It is one of the most distant objects that can potentially be seen with the naked eye under ideal conditions.
3. The galaxy contains an exceptionally large and bright H II region called NGC 604, which is a major site of star formation.
4. M33 may be gravitationally bound to the Andromeda Galaxy and could be involved in the future collision between Andromeda and the Milky Way.
Brightness, distance and size
Messier 33 has an apparent magnitude of 5.72, making it potentially visible to the naked eye under very dark skies. Located approximately 2.73 million light-years away, it spans about 60,000 light-years in diameter. In the night sky, the galaxy appears to cover an area of about 70.8 × 41.7 arcminutes, which is more than twice the apparent diameter of the full Moon.
