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
NGC 3938 imaged by Mount Lemmon SkyCenter of the University of Arizona
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 (type II, mag. 13.7) was discovered by Paul Wild on 28 December 1961.^[6][7] [Note: some sources incorrectly list the discovery date as 2 January 1962.]
• SN 1964L (type Ic, mag. 13.3) was discovered by Paul Wild on 11 December 1964.^[8][9]
• SN 2005ay (type II, mag. 15.6) was discovered by Doug Rich on 27 March 2005.^[10][11]
• SN 2017ein (type Ic, mag. 17.6) was discovered by Ron Arbour on 25 May 2017 and peaked at magnitude 14.9.^[12][13] 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.^[14]
• SN 2022xlp (type Ia, mag. 17) was discovered by Kōichi Itagaki on 13 October 2022.^[15]

Gallery

• 
  Artist's impression of progenitor star to a type Ic supernova in NGC 3938.^[16]
• 
  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