IC 438

IC 438 is a spiral galaxy in the constellation of Lepus. Its velocity with respect to the cosmic microwave background is 3,199±6 km/s, which corresponds to a Hubble distance of 153.9 ± 10.8 Mly (47.18 ± 3.30 Mpc).^[1] However, 17 non-redshift measurements give a much closer distance of 136.45 ± 4.29 Mly (41.835 ± 1.314 Mpc).^[2] It was discovered by American astronomer Lewis Swift on 7 January 1891.^[3][4]

IC 438
IC 438 imaged by the Hubble Space Telescope in 2021
Observation data (J2000 epoch)
Constellation	Lepus
Right ascension	05h 53m 00.0676s[1]
Declination	−17° 52′ 33.684″[1]
Redshift	0.004256±0.000006[1]
Heliocentric radial velocity	3,123±4 km/s[1]
Distance	136.45 ± 4.29 Mly (41.835 ± 1.314 Mpc)[1]
Group or cluster	IC 438 Group (LGG 134)
Apparent magnitude (V)	12.74[1]
Characteristics
Type	SA(rs)c[1]
Size	~155,100 ly (47.55 kpc) (estimated)[1]
Apparent size (V)	2.8′ × 2.1′[1]
Other designations
ESO 555- G 009, IRAS 05508-1753, UGCA 115, MCG -03-15-025, PGC 18047[1]

IC 438 is a Seyfert I Galaxy, i.e. it has a quasar-like nucleus with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, the host galaxy is clearly detectable.^[5]

IC 438 Group

According to A.M. Garcia, IC 438 is one of five members of the IC 438 galaxy group (also known as LGG 134), which includes IC 2143, UGCA 113, MCG -03-15-021, and ESO 555- G 005.^[6]

Supernovae

Three supernovae have been observed in IC 438:

• SN 1997B (Type Ic, mag. 16.5) was discovered by Alessandro Gabrijelcic on 13 January 1997.^[7][8]
• SN 2016blx (Type II, mag. 16.5) was discovered by the Backyard Observatory Supernova Search (BOSS) on 9 April 2016.^[9]
• SN 2017gbb (Type Iax[02cx-like], mag. 16.39) was discovered by the Gaia Photometric Science Alerts programme on 9 August 2017.^[10]

See also

• List of IC objects