- SN 2011fe, initially designated PTF 11kly, is a star which perished in a supernova event that is currently visible from Earth.
- A nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner. A supernova is a stellar explosion that is more energetic than a nova.
- The star SN 2011fe has been discovered on 24 August 2011 by Palomar Transient Factory (PTF) survey. The star, formerly a white dwarf, is located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. On 13 September 2011, it reached its maximum brightness of apparent magnitude +9.9 which equals an absolute magnitude of about -19, equal to 2.5 billion Suns. At +10 apparent magnitude around 5 September, SN 2011fe was visible in small telescopes.