NGC 5806 contains a star that was catalogued as asupernova (SN Hunt 248), but turned out to be asupernova 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☉.[5]
Supernova SN 2004dg in NGC 5806
NGC 5806 has also hosted several true supernovae.SN 2004dg (type II, mag. 17.1)[6] was around 100 times brighter than SN Hunt 248. The progenitor of SN 2004dg has not been detected and is expected to have been a relatively low mass, low luminosity,red supergiant.[7] The other supernovae areSN 2012P (type IIb, mag. 15)[8] andiPTF13bvn (typeIb, mag. 17.2), which was discovered on 16 June 2013.[9]