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Triangulum Galaxy ❍｜Definition｜1st｜20251119205401-00-⌔
Triangulum Galaxy
The Triangulum Galaxy is a spiral galaxy 2.878 million light-years (ly) from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. With the D 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.1 It is believed to be a satellite of the Andromeda Galaxy or on its rebound into the latter due to their interactions, velocities,2 and proximity to one another in the night sky. It also has an H II nucleus.3
Printed 2026-06-28.
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Link to original Footnotes
Ryden, Barbara; Peterson, Bradley M. (2010). Foundations of astrophysics. San Francisco: Addison-Wesley. ISBN 978-0-321-59558-4. ↩
Brunthaler, Andreas; Reid, Mark J.; Falcke, Heino; Greenhill, Lincoln J.; et al. (2005). “The Geometric Distance and Proper Motion of the Triangulum Galaxy (M33)”. Science. 307 (5714): 1440–1443. arXiv:astro-ph/0503058. Bibcode:2005Sci…307.1440B. doi:10.1126/science.1108342. PMID 15746420. S2CID 28172780. ↩
Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W. (October 1997). “A Search for Dwarf Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies”. The Astrophysical Journal Supplement Series. 112 (2): 315–390. arXiv:astro-ph/9704107. Bibcode:1997ApJS..112..315H. doi:10.1086/313041. ISSN 0067-0049. S2CID 17086638. ↩
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