NGC 3938

NGC 3938 is an unbarred spiral galaxy in the Ursa Major constellation. It was discovered on 6 February 1788 by William Herschel. It is one of the brightest spiral galaxies in the Ursa Major South galaxy group and is roughly 67,000 light years in diameter.^[3] It is approximately 43 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.^[4] The spiral arms of the galaxy contain many areas of ionized atomic hydrogen gas, more so towards the center.^[5]

NGC 3938
Observation data (J2000 epoch)
Constellation	Ursa Major[1]
Right ascension	11h 52m 42.9s[1]
Declination	+44° 07′ 17″[1]
Distance	43 Mly
Apparent magnitude (V)	10.9[1]
Characteristics
Type	SA(s)c[2]
Apparent size (V)	5.4′ × 4.9′[1]
Other designations
UGC 6856, MCG +07-25-001, PGC 37229[2]

Supernovae

Five supernovae have been identified within NGC 3938. SN 1961U (mag. 13.7) was discovered on 2 January 1962.^[6] SN 1964L (mag. 13.3) was discovered on 11 December 1964.^[7] SN 2005ay is a type II supernova that was discovered on 27 March 2005 and had a magnitude of 15.6.^[8] SN 2017ein is a type Ic supernova that was discovered on 25 May 2017 and peaked at magnitude 14.9.^[9] 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.^[10] SN 2022xlp is a type Ia supernova that was discovered on 13 October 2022 by Kōichi Itagaki.

Gallery

• 
  Artist's impression of progenitor star to a type Ic supernova in NGC 3938.^[11]
• 
  Spiral galaxy NGC 3938, by HST. Location of SN 2005ay remnant is marked.
• 
  NGC 3938 with supernova SN 2005ay
• 
  The location of SN 2017ein, by HST.
• 
  NGC 3938 by the Sloan Digital Sky Survey

References

1. George Normandin (5 May 2005). "Spiral Galaxy NGC 3839". kopernik.org. Retrieved 30 December 2011.
2. "Results for object NGC 3938 (NGC 3938)". NASA/IPAC Extragalactic Database. California Institute of Technology. Retrieved 28 February 2021.
3. "The Ursa Major Groups". Atlas of the Universe. Retrieved 30 December 2011.
4. 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.
5. 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.
6. Transient Name Server entry for SN 1961U. Retrieved 25 March 2023.
7. Transient Name Server entry for SN 1964L. Retrieved 25 March 2023.
8. "Supernova 2005ay in NGC 3938". Rochester Astronomy. Retrieved 29 January 2013.
9. "Supernovae 2017ein in NGC 3938". www.rochesterastronomy.org. Retrieved 29 June 2017.
10. 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.
11. "Artist's impression of progenitor star to a type Ic supernova". www.spacetelescope.org. Retrieved 20 November 2018.

External links

• Media related to NGC 3938 at Wikimedia Commons