Friday, January 30, 2009

NGC 5457: By Haileyesus Workneh

Messier 101 (M101, NGC 5457) was discovered by Pierre Méchain on March 27, 1781. The distance of M101 has been determined by the measurement of Cepheid variables with the Hubble Space Telescope in 1994/95 to be about 24 +/- 2 million light years, by the HST H0 Key Project Team. Three supernovae have been discovered in M101: The first one, SN 1909A, appeared on January 26, 1909. The second supernova 1951H was of type II, occurred in September 1951 amd the third, SN 1970G, also type II, was discovered on July 30, 1970.<READ MORE>

No comments:

Post a Comment