Supernovae
Five supernovae have been identified in the M100 galaxy. In March 1901 the first supernova of M100 was found, SN 1901B, a type I supernova found when magnitude 15.6 at a distance from its nucleus. SN 1914A was then discovered in February to March 1914; its type was undeterminable but was found when magnitude 15.7 at some distance from the center. Observations of M100 from February 21, 1960 to June 17, 1960 led to the discovery of SN 1959E, another type I supernova, with the faintest magnitude, 17.5, among the five found, at 58"E and 21"S from its nucleus. On April 15, 1979, the first type II supernova found in the M100 galaxy was discovered; however the star SN 1979C faded quickly; later observations from x-ray to radio wavelengths revealed its remnant. The latest supernova was discovered February 7, 2006; the star SN 2006X had a magnitude of 15.3 when discovered two weeks before fading to magnitude +17.
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