The Triangulum Galaxy (also referred to as Messier 33 or NGC 598) is a w:spiral galaxy roughly Three million light-years away within the w:constellation w:Triangulum. The galaxy can be typically informally known as the Pinwheel Galaxy by some newbie astronomy references[2]
and in some public outreach web sites.[3]
Nevertheless, the w:SIMBAD Astronomical Database, knowledgeable astronomy database that incorporates formal designations for astronomical objects, signifies that the title “Pinwheel Galaxy” is used to confer with w:Messier 101,[4]
and several other different newbie astronomy assets and different public outreach web sites additionally establish Messier 101 by that title.[5][6]
It’s the third largest galaxy within the w:Native Group, a w:group of galaxies that additionally incorporates the w:Milky Method Galaxy and the w:Andromeda Galaxy, and it might be a gravitationally certain companion of the Andromeda Galaxy. The w:Pisces Dwarf (LGS 3), one of many small Native Group member galaxies, is probably a w:satellite tv for pc of Triangulum.

Normal info

Triangulum (M33) and Andromeda (M31)

The Triangulum Galaxy might be seen with the bare eye beneath exceptionally good situations. Whereas the fainter and extra distant galaxy w:Messier 81 has additionally been seen with the bare eye by very skilled observers. Nevertheless, some newbie astronomers could confuse the item with the close by w:NGC 752, an w:open cluster that’s brighter than the Triangulum Galaxy.[citation needed] No recognized pre-telescopic observer notes it, which isn’t shocking: given its indistinctness, it isn’t prone to be observed as an object except one already is aware of of its existence.

The Triangulum Galaxy was most likely found by w:Giovanni Batista Hodierna earlier than 1654, who could have grouped it along with w:open cluster NGC 752. It was independently found by w:Charles Messier in 1764, who catalogued it as M33 on August 25. M33 was additionally catalogued independently by w:William Herschel on September 11, 1784 quantity H V.17. It was among the many first “w:spiral nebulae” recognized as such by Lord Rosse.

Herschel additionally cataloged The Triangulum Galaxy’s brightest and largest w:H II area (diffuse w:emission nebula containing w:ionized w:hydrogen) as H III.150 individually from the galaxy itself, which ultimately obtained NGC quantity 604. As seen from Earth NGC 604 is positioned northeast of the galaxy’s central core, and is without doubt one of the largest H II areas recognized with a diameter of almost 1500 w:light-years and a spectrum much like the w:Orion Nebula. Herschel additionally famous Three different smaller H II areas (NGC 588, 592 and 595).

In 2005, utilizing observations of two water masers on reverse sides of Triangulum through the w:VLBA, researchers have been, for the primary time, in a position to estimate the angular rotation and correct movement of Triangulum. A velocity of 190 ± 60 km/s relative to the Milky Method is computed which implies Triangulum is transferring in direction of Andromeda.[7]

In 2007, a black gap about 15.7 instances the mass of the Solar was detected within the galaxy utilizing information from the w:Chandra X-ray Observatory. The black gap, named M33 X-7, orbits a companion star which it eclipses each 3.5 days.[8]

The galaxy has an H II nucleus.[9]


At the least three methods have been used to measure distances to M 33. Utilizing the w:Cepheid variable methodology, an estimate of two.77 ± 0.13 Mly (850 ± 40 kpc) was achieved in 2004.[10][11]

Additionally 2004, the w:Tip of the Pink Large Department (TRGB) methodology was used to derive a distance estimate of two.59 ± 0.08 Mly (794 ± 23 kpc).[12]

In 2006, a gaggle of astronomers introduced the invention of an eclipsing binary star within the Triangulum Galaxy. By finding out the eclipses of the celebrities, the astronomers have been in a position to measure their sizes. Understanding the sizes and temperatures of the celebrities they have been in a position to measure the w:absolute magnitude of the celebrities. When the visible and absolute magnitudes are recognized, the gap to the star might be measured. The celebs lie on the distance of three.1 ± 0.2 Mly (940 ± 70 kpc).[13][14]

Averaged collectively, all these distance measurements give a mixed distance estimate of two.81 ± 0.09 Mly (861 ± 28 kpc).[14]

References in fiction

Fundamental web page: Galaxies in fiction

Within the episode “w:The place No One Has Gone Earlier than” of the primary season of w:Star Trek: The Subsequent Technology, the Enterprise is hurled into the far aspect of M33 by an alien customer recognized solely as “The Traveler”.

Within the TV sequence Andromeda, Triangulum Galaxy is without doubt one of the three galaxies forming the Programs Commonwealth, together with The Milky Method and Andromeda.

Within the 2007 laptop sport w:Crysis, the alien antagonists of the sport are stated to have originated from the galaxy M33.

Within the comic-book sequence w:Yoko Tsuno, the Vineans originated from M33, with the primary point out of it being within the sixth album w:Les Trois soleils de Vinéa (The Three Suns of Vinea).


  1. abcdefgh “NASA/IPAC Extragalactic Database”. Outcomes for NGC 598. Retrieved 2006-12-01. 
  2. S. J. O’Meara (1998). The Messier Objects. Cambridge: Cambridge College. ISBN 0-521-55332-6. 
  3. “NASA Spitzer Telescope Reveals Pinwheel Galaxy’s Hidden Wonders”. Retrieved 2007-04-07. 
  4. “SIMBAD Astronomical Database”. Outcomes for Messier 101.. Retrieved 2007-04-07. 
  5. “Messier Object 101”. Retrieved 2007-04-07. 
  6. “Better of AOP: M101: Pinwheel Galaxy”. Retrieved 2007-04-07. 
  7. Brunthaler, Andreas; Reid, Mark J.; Falcke, Heino; Greenhill, Lincoln J.; Henkel, Christian (2005). “The Geometric Distance and Correct Movement of the Triangulum Galaxy (M33)”. Science 307 (5714): 1440–1443. doi:10.1126/science.1108342. PMID 15746420.…307.1440B. 
  8. Morcone, Jennifer, Heaviest Stellar Black Gap Found in Close by Galaxy, w:Chandra X-ray Observatory press launch, Template:Date
  9. Ho, Luis C.; Filippenko, Alexei V.; Sargent, Wallace L. W. (October 1997), “A Seek for “Dwarf” Seyfert Nuclei. III. Spectroscopic Parameters and Properties of the Host Galaxies”, The Astrophysical Journal Complement Collection 112: 315–390, doi:10.1086/313041, 
  10. I. D. Karachentsev, V. E. Karachentseva, W. Okay. Hutchmeier, D. I. Makarov (2004). “A Catalog of Neighboring Galaxies”. Astronomical Journal 127: 2031–2068. doi:10.1086/382905.….127.2031Okay. 
  11. Karachentsev, I. D.; Kashibadze, O. G. (2006). “Plenty of the native group and of the M81 group estimated from distortions within the native velocity subject”. Astrophysics 49 (1): 3–18. doi:10.1007/s10511-006-0002-6.…..49….3K. 
  12. McConnachie, A. W.; Irwin, M. J.; Ferguson, A. M. N.; Ibata, R. A.; Lewis, G. F.; Tanvir, N. (Could 2004), “Figuring out the placement of the tip of the crimson large department in outdated stellar populations: M33, Andromeda I and II”, Month-to-month Notices of the Royal Astronomical Society 350 (1): 250, doi:10.1111/j.1365-2966.2004.07637.x, 
  13. Bonanos, A. Z.; Stanek, Okay. Z.; Kudritzki, R. P.; Macri, L.; Sasselov, D. D.; Kaluzny, J.; Bersier, D.; Bresolin, F.; Matheson, T.; Mochejska, B. J.; Przybilla, N.; Szentgyorgyi, A. H.; Tonry, J.; Torres, G. (2006). “The First DIRECT Distance to a Indifferent Eclipsing Binary in M33”. Astrophysics and House Science On-line First: 207. doi:10.1007/s10509-006-9112-1. 
  14. ab common(850 ± 40, 794 ± 23, 940 ± 70) = ((850 + 794 + 940) / 3) ± ((40² + 23² + 70²)0.5 / 3) = 861 ± 28

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