Triangulum Galaxy

Triangulum Galaxy
M33 - Triangulum Galaxy.jpg
Triangulum Galaxy – Messier 33
Observation data (J2000 epoch)
Right ascension01h 33m 50.02s[1]
Declination+30° 39′ 36.7″[1]
Redshift-0.000607 ± 0.000010[1]
Helio radial velocity-179 ± 3 km/s[2]
Galactocentric velocity-44 ± 6 km/s[2]
Distance2.38 to 3.07 Mly (730 to 940 kpc)[3][4]
Apparent magnitude (V)5.72[1]
Mass5 × 1010[5] M
Number of stars40 billion (4×1010)[6]
Size~60,000 ly (diameter)[6]
Apparent size (V)70.8 × 41.7 moa[1]
Other designations
NGC 0598, MCG+05-04-069, UGC 1117, PGC 5818[2]
See also: Galaxy, List of galaxies

The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Milky Way and the Andromeda Galaxy. It is one of the most distant permanent objects that can be viewed with the naked eye.

The galaxy is the smallest spiral galaxy in the Local Group and it is believed to be a satellite of the Andromeda Galaxy due to their interactions, velocities[7], and proximity to one another in the night sky. It also has an H-II nucleus.[8]


The galaxy gets its name from the constellation Triangulum, which is where it can be spotted.

The Triangulum Galaxy is sometimes informally referred to as the "Pinwheel Galaxy" by some amateur astronomy references[9] and in some public outreach websites.[10] However, the SIMBAD Astronomical Database, a professional astronomy database that contains formal designations for astronomical objects, indicates that the name Pinwheel Galaxy is used to refer to Messier 101,[11] and several other amateur astronomy resources and other public outreach websites also identify Messier 101 by that name.[12][13]

Other Languages
العربية: مسييه 33
azərbaycanca: NGC 598
Bân-lâm-gú: Messier 33
беларуская: M33 (аб’ект Месье)
беларуская (тарашкевіца)‎: Галяктыка Трыкутніка
български: M33
corsu: M33
Deutsch: Dreiecksnebel
Esperanto: M33
hrvatski: Messier 33
Bahasa Indonesia: Galaksi Triangulum
Lëtzebuergesch: Messier 33
Malagasy: Messier 33
മലയാളം: മെസ്സിയർ 33
مازِرونی: مسیه ۳۳
Bahasa Melayu: Galaksi Triangulum
Nederlands: Driehoeknevel
norsk nynorsk: Triangelgalaksen
occitan: Messier 33
Simple English: Triangulum galaxy
slovenščina: Galaksija v Trikotniku
српски / srpski: Месје 33
srpskohrvatski / српскохрватски: Messier 33
Tiếng Việt: Thiên hà Tam Giác