NGC 5806

NGC 5806 is an intermediate spiral galaxy in the constellation Virgo. It was discovered by German-British astronomer William Herschel on 24 February 1786.^[5] It is located about 70 million light-years (21 Megaparsecs) away from the Milky Way.^[3] It is a member of the NGC 5846 Group.^[2]

NGC 5806
NGC 5806 imaged by the Hubble Space Telescope
Observation data (J2000 epoch)
Constellation	Virgo
Right ascension	15h 00m 00.4123s[1]
Declination	+01° 53′ 28.756″[1]
Redshift	0.004493[1]
Heliocentric radial velocity	1346 ± 21 km/s[2]
Distance	68 Mly (21 Mpc)[3]
Group or cluster	NGC 5806 Group (LGG 392)[4]
Apparent magnitude (V)	11.70[3]
Apparent magnitude (B)	12.40[3]
Characteristics
Type	SAB(s)b[1][3]
Size	~73,900 ly (22.65 kpc) (estimated)[1]
Apparent size (V)	3.1′ × 1.6′[3]
Other designations
IRAS 14574+0205, UGC 9645, MCG +00-38-014, PGC 53578, CGCG 020-041[2][1]

Supernovae and Imposter

Supernova SN 2004dg in NGC 5806

Three supernovae and one supernova imposter have been observed in NGC 5806:

• SN 2004dg (Type II, mag. 17.1) was discovered by Associazione Ternana Astrofili on 19 July 2004.^[6][7] The progenitor of SN 2004dg has not been detected and is expected to have been a relatively low mass, low luminosity, red supergiant.^[8]
• SN 2012P (Type IIb, mag. 15.0) was discovered by Fabio Briganti on 22 January 2012.^[9][10] Originally classified as a Type Ib/c, it was later determined to be Type IIb.^[11] Later analysis concluded that the progenitor had an initial mass of 15.2 M_☉.^[12]
• iPTF13bvn (Type Ib, mag. 17.2) was discovered by the Palomar Transient Factory on 16 June 2013.^[13][14]
• SN Hunt 248 (also known as AT 2014ib) was discovered by the Catalina Real-time Transient Survey and Stan Howerton on 21 May 2014. It was initially catalogued as a supernova, but was later classified as a supernova imposter. The progenitor was detected as a cool hypergiant with an absolute visual magnitude of −9 and 400,000 times more luminous than the sun. The eruption saw it increase in luminosity to around 80,000,000 L_☉.^[15] Later analysis concluded that this object is a luminous red nova.^[16][17]