NGC 2403

NGC 2403, or Caldwell 7, is an intermediate spiral galaxy in the constellation of Camelopardalis. NGC 2403 is a member of the M81 Group. It was discovered by astronomer William Herschel in 1 November 1788.^[1] It is located at about 9.7 million light-years away from Earth.^[2]

The size is estimated at 90,300 light-years across.^[3] It is known for its resemblance to the Triangulum Galaxy (M33). It has many star-forming regions (H II regions). In 2004, a supernova was discovered in this galaxy, SN 2004dj. It is one of the brightest and closest supernovae observed in the 21st century.^[4]

References

↑ "New General Catalog Objects: NGC 2400 - 2449". cseligman.com. Retrieved 2026-07-05.
↑ Carlin, Jeffrey L.; et al. (2019-11-26). "Tidal Destruction in a Low-mass Galaxy Environment: The Discovery of Tidal Tails around DDO 44*". The Astrophysical Journal. 886 (2): 109. arXiv:1906.08260. Bibcode:2019ApJ...886..109C. doi:10.3847/1538-4357/ab4c32.
↑ "NGC 2403 | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2026-07-05.
↑ "A Bright Supernova in the Nearby Galaxy NGC 2403". NASA Science. 2 September 2004. Retrieved 2026-07-05.

[1] "New General Catalog Objects: NGC 2400 - 2449". cseligman.com. Retrieved 2026-07-05.

[2] Carlin, Jeffrey L.; et al. (2019-11-26). "Tidal Destruction in a Low-mass Galaxy Environment: The Discovery of Tidal Tails around DDO 44*". The Astrophysical Journal. 886 (2): 109. arXiv:1906.08260. Bibcode:2019ApJ...886..109C. doi:10.3847/1538-4357/ab4c32.

[3] "NGC 2403 | NASA/IPAC Extragalactic Database". ned.ipac.caltech.edu. Retrieved 2026-07-05.

[4] "A Bright Supernova in the Nearby Galaxy NGC 2403". NASA Science. 2 September 2004. Retrieved 2026-07-05.

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