Wikipedia

NGC 3938

NGC 3938 is an unbarred spiral galaxy in the Ursa Major constellation. It was discovered by German-British astronomer William Herschel on 6 February 1788.[3] It is one of the brightest spiral galaxies in the Ursa Major South galaxy group and is roughly 76,000 light years in diameter.[2][4] It is approximately 41.4 million light years away from Earth.[1] NGC 3938 is classified as type Sc under the Hubble sequence, a loosely wound spiral galaxy with a smaller and dimmer bulge.[5] The spiral arms of the galaxy contain many areas of ionized atomic hydrogen gas, more so towards the center.[6]

NGC 3938
NGC 3938 imaged by Mount Lemmon SkyCenter of the University of Arizona
Observation data (J2000 epoch)
ConstellationUrsa Major[1]
Right ascension11h 52m 49.4319s[2][1]
Declination+44° 07′ 14.840″[2]
Redshift0.002695[2]
Heliocentric radial velocity808±2 km/s[2]
Distance41.40 ± 9.00 Mly (12.694 ± 2.760 Mpc)[2]
Apparent magnitude (V)10.9[1]
Characteristics
TypeSA(s)c[2]
Size~76,400 ly (23.42 kpc) (estimated)[2]
Apparent size (V)5.4′ × 4.9′[1]
Other designations
IRAS 11502+4423, UGC 6856, MCG +07-25-001, PGC 37229, CGCG 214-034[2]

NGC 3938 is a member of the NGC 4111 Group,[7] which is part of the Ursa Major Cloud and is the second largest group in the cloud after the NGC 3992 Group.[8][9][10]

Supernovae and Luminous Red Nova

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NGC 3938 with SN 2005ay

Five supernovae have been identified within NGC 3938:

  • SN 1961U (Type II, mag. 13.7) was discovered by Paul Wild on 28 December 1961.[11][12][a]
  • SN 1964L (Type Ic, mag. 13.3) was discovered by Paul Wild on 11 December 1964.[13][14]
  • SN 2005ay (Type II, mag. 15.6) was discovered by Doug Rich on 27 March 2005.[15][16][17]
  • SN 2017ein (Type Ic, mag. 17.6) was discovered by Ron Arbour on 25 May 2017 and peaked at magnitude 14.9.[18][19] Images taken before the explosion point to a progenitor mass between ~47-48M☉, if it was in a single star system, and ~60-80M☉, if it was in a binary star system.[20]
  • SN 2022xlp (Type Ia, mag. 17) was discovered by Kōichi Itagaki on 13 October 2022.[21]

One luminous red nova has been observed in NGC 3938:

  • AT 2022ckk (type LRN, mag. 19.6766) was discovered by the Automatic Learning for the Rapid Classification of Events (ALeRCE) on 13 February 2022.[22]
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See also

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Notes

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  1. ↑ Some sources incorrectly list the discovery date as 2 January 1962.

References

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  1. 1 2 3 4 5 George Normandin (5 May 2005). "Spiral Galaxy NGC 3839". kopernik.org. Retrieved 30 December 2011.
  2. 1 2 3 4 5 6 7 8 9 "Results for object NGC 3938". NASA/IPAC Extragalactic Database. NASA and Caltech. Retrieved 28 February 2021.
  3. ↑ Seligman, Courtney. "New General Catalogue Objects: NGC 3938". Celestial Atlas. Retrieved 7 June 2025.
  4. ↑ "The Ursa Major Groups". Atlas of the Universe. Retrieved 30 December 2011.
  5. ↑ van der Kruit, P.C.; Shostak, G.S. (1982). "Studies of Nearly Face-on Spiral Galaxies" (PDF). Astronomy and Astrophysics. 105: 351–358. Bibcode:1982A&A...105..351V. Retrieved 25 June 2014.
  6. ↑ Jiménez-Vicente, J.; E. Battaner; M. Rozas; H. Castañeda; et al. (1999). "Fabry-Perot observations of the ionized gas in NGC 3938" (PDF). Astronomy and Astrophysics. 342: 417–425. arXiv:astro-ph/9811391. Bibcode:1999A&A...342..417J.
  7. ↑ Makarov, Dmitry; Karachentsev, Igor (21 April 2011). "Galaxy groups and clouds in the local (z∼ 0.01) Universe: Galaxy groups in the local Universe". Monthly Notices of the Royal Astronomical Society. 412 (4): 2498–2520. arXiv:1011.6277. doi:10.1111/j.1365-2966.2010.18071.x.
  8. ↑ Karachentsev, I. D.; Nasonova, O. G.; Courtois, H. M. (1 March 2013). "Anatomy of Ursa Majoris". Monthly Notices of the Royal Astronomical Society. 429 (3): 2264–2273. arXiv:1211.5975. doi:10.1093/mnras/sts494. ISSN 1365-2966.
  9. ↑ Pak, Mina; Rey, Soo-Chang; Lisker, Thorsten; Lee, Youngdae; Kim, Suk; Sung, Eon-Chang; Jerjen, Helmut; Chung, Jiwon (29 September 2014). "The properties of early-type galaxies in the Ursa Major cluster". Monthly Notices of the Royal Astronomical Society. 445 (1): 630–647. arXiv:1409.3070. doi:10.1093/mnras/stu1722. ISSN 0035-8711.
  10. ↑ Ai, Mei; Zhu, Ming; Yu, Nai-ping; Xu, Jin-long; Liu, Xiao-lan; Jing, Yingjie; Jiao, Qian; Liu, Yao; Zhang, Chuan-peng; Wang, Jie; Jiang, Peng (1 April 2025). "Formation of the Dark Matter–Deficient S0 Galaxy NGC 4111 under the Tidal Interactions". The Astrophysical Journal Letters. 982 (2): L52. arXiv:2503.05171. Bibcode:2025ApJ...982L..52A. doi:10.3847/2041-8213/adbeee. ISSN 2041-8205.
  11. ↑ Schürer, Max; Wild, P. (4 January 1962). Thernöe, K. A. (ed.). "SUPERNOVA IN NGC 3938". Central Bureau for Astronomical Telegrams. 1787. Observatory Copenhagen, IAU: 3. Retrieved 27 November 2024.
  12. ↑ "SN 1961U". Transient Name Server. IAU. Retrieved 27 November 2024.
  13. ↑ Wild, P.; Bertola (29 December 1964). Thernöe, K. A. (ed.). "SUPERNOVA IN NGC 3938". Central Bureau for Astronomical Telegrams. 1882. Observatory Copenhagen, IAU: 1. Retrieved 27 November 2024.
  14. ↑ "SN 1964L". Transient Name Server. IAU. Retrieved 27 November 2024.
  15. ↑ Rich, D. (2005). "Supernova 2005ay in NGC 3938". Central Bureau Electronic Telegrams (128): 1. Bibcode:2005CBET..128....1R.
  16. ↑ Bishop, David. "Supernova 2005ay in NGC 3938". Rochester Astronomy. Retrieved 29 January 2013.
  17. ↑ "SN 2005ay". Transient Name Server. IAU. Retrieved 27 November 2024.
  18. ↑ "SN 2017ein". Transient Name Server. IAU. Retrieved 27 November 2024.
  19. ↑ Bishop, David. "Supernovae 2017ein in NGC 3938". www.rochesterastronomy.org. Retrieved 29 June 2017.
  20. ↑ Van Dyk, Schuyler; et al. (15 July 2018). "SN 2017ein and the Possible First Identification of a Type Ic Supernova Progenitor". The Astrophysical Journal. 860 (2): 90. arXiv:1803.01050. Bibcode:2018ApJ...860...90V. doi:10.3847/1538-4357/aac32c. hdl:10150/628570. S2CID 56265423.
  21. ↑ "SN 2022xlp". Transient Name Server. IAU. Retrieved 27 November 2024.
  22. ↑ "AT 2022ckk". Transient Name Server. IAU. Retrieved 7 June 2025.
  23. ↑ "Artist's impression of progenitor star to a type Ic supernova". www.spacetelescope.org. Retrieved 20 November 2018.
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