The Triangulum Galaxy (also known as Spiral Galaxy M33 , Messier Object 33 , Messier 33, M33 or NGC 598) is a spiral galaxy located in the constellation Triangulum . Is small compared with its neighbors over as the Milky Way and Andromeda Galaxy (with between 30 billion and 40 billion stars compared to between 200 billion and 400 billion in the first and the second billion), but its size is average similar to that of other spiral galaxies in the universe .
M33 is a member of Local Group galaxies of -third in brightness and size, and appears to be gravitationally bound to Andromeda, which is 720000 years light of it and it orbits in a highly elliptical orbit . LGS 3 , one of the smallest members of the Local Group, it may be a satellite galaxy of it.
This galaxy was probably discovered by Giovanni Battista Odierna before 1654 , who grouped together with the open cluster now known as NGC 752 . Charles Messier independently discovered 1764, calling it the M33 August 25. The Triangulum Galaxy was also cataloged by William Herschel the September 11 of 1784, assigning it the number H V.17. M33 is among the first "Nebulae spirals "identified by Lord Rosse .
most appointed Herschel H II region of this galaxy ( diffuse emission nebula containing ionized hydrogen) as H III.150 separating and naming it NGC 604 . View from the Earth , NGC 604 is located northeast of the galactic center, and is one of the largest H II regions known, with a diameter of 1500 light years and a spectrum similar to M42 .
Although it can be compared with NGC 604, Triangle HII regions are also so big and bright with its own NGC number, like with NGC 588, NGC 592 and NGC 595.The Triangulum Galaxy can be seen with the naked eye under exceptional conditions, and for many people, is the object visible to the naked eye more distant. However, it is very large and diffuse, and the best instrument to observe are some binoculars, and may even under very good conjecture with them spiral arms, or a telescope working at very low magnification. The most important and interesting that experts have highlighted the M33 is that it is a real hotbed of rising stars, where suns arise much faster than we are used to our Milky Way, NGC 604 in addition to containing some of the richest stellar associations and bright Local Group.