NGC 3681 is an intermediate spiral galaxy in the constellation Leo. The galaxy lies about 90 million light years away from Earth, which means, given its apparent dimensions, that NGC 3681 is approximately 80,000 light years across.[1] It was discovered by William Herschel on April 17, 1784.[3]

NGC 3681 is characterised as an intermediate spiral galaxy, meaning it has a short bar. The bar makes the bulge appear elliptical. The disk of the galaxy is smooth and low surface brightness. A ring is formed at the inner part of the disk.[4] The galaxy has multiple flocculent spiral arms and fragments. There are higher surface brightness inner arms and faitner outer arms. HII regions have been spotted in both.[5] In ultraviolet the galaxy appears more extended than in optical. Also the inner ring is more pronounced.[6] The galaxy also has an excess of hydrogen. The galaxy is seen nearly face-on, at an inclination of about 15°.[6]

NGC 3681 is a member of the NGC 3686 Group. Other members of the group include NGC 3684, NGC 3686, and NGC 3691.[7] A. M. Garcia considers the galaxies NGC 3592, NGC 3626, NGC 3655, NGC 3659, and NGC 3608 as member of the group, named LGG 237.[8] The group is part of the Leo II Groups, a large cloud of galaxies in the Virgo Supercluster.[9]

References

  1. ^ a b c d e f g h i j "Results for object NGC 3681". NASA/IPAC Extragalactic Database. NASA and Caltech. Retrieved 15 February 2025.
  2. ^ "Revised NGC Data for NGC 3681". spider.seds.org. Retrieved 30 March 2024.
  3. ^ Seligman, Courtney. "NGC 3681 (= PGC 35193)". Celestial Atlas. Retrieved 19 November 2018.
  4. ^ Eskridge, Paul B.; Frogel, Jay A.; Pogge, Richard W.; Quillen, Alice C.; Berlind, Andreas A.; Davies, Roger L.; DePoy, D. L.; Gilbert, Karoline M.; Houdashelt, Mark L.; Kuchinski, Leslie E.; Ramirez, Solange V.; Sellgren, K.; Stutz, Amelia; Terndrup, Donald M.; Tiede, Glenn P. (November 2002). "Near-Infrared and Optical Morphology of Spiral Galaxies". The Astrophysical Journal Supplement Series. 143 (1): 73–111. arXiv:astro-ph/0206320. Bibcode:2002ApJS..143...73E. doi:10.1086/342340.
  5. ^ Sandage, A., Bedke, J. (1994), The Carnegie Atlas of Galaxies. Volume I, Carnegie Institution of Washington
  6. ^ a b Marino, A.; Plana, H.; Rampazzo, R.; Bianchi, L.; Rosado, M.; Bettoni, D.; Galletta, G.; Mazzei, P.; Buson, L.; Ambrocio-Cruz, P.; Gabbasov, R. F. (1 January 2013). "Galaxy evolution in nearby loose groups – II. Photometric and kinematic characterization of USGC U268 and USGC U376 group members in the Leo cloud★". Monthly Notices of the Royal Astronomical Society. 428 (1): 476–501. doi:10.1093/mnras/sts039.
  7. ^ Makarov, Dmitry; Karachentsev, Igor (21 April 2011). "Galaxy groups and clouds in the local (z~ 0.01) Universe". Monthly Notices of the Royal Astronomical Society. 412 (4): 2498–2520. arXiv:1011.6277. Bibcode:2011MNRAS.412.2498M. doi:10.1111/j.1365-2966.2010.18071.x. S2CID 119194025.
  8. ^ Garcia, A. M. (1 July 1993). "General study of group membership. II. Determination of nearby groups". Astronomy and Astrophysics Supplement Series. 100: 47–90. Bibcode:1993A&AS..100...47G. ISSN 0365-0138.
  9. ^ "The Leo II Groups". www.atlasoftheuniverse.com. Retrieved 12 February 2025.
Allikas: https://en.wikipedia.org/wiki/NGC_3681
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