SN 2011fe, initially designated PTF 11kly, is a star undergoing a type Ia supernova event, discovered by the Palomar Transient Factory (PTF) survey on the 24 August 2011 during an automated review of images of the Messier 101 from the nights of the 22nd and 23rd of August 2011. The star, formerly a white dwarf, is located in Messier 101, the Pinwheel Galaxy, 21 million light years from Earth. It was observed by the PTF survey very near the beginning of its supernova event, when it was approximately 1 million times too dim to be visible to the naked eye. It is the youngest type Ia ever discovered.[3]
The Palomar Transient Factory is an automated telescopic survey that scans the sky for transient and variable astronomical events. Information is fed to the National Energy Research Scientific Computing Center (NERSC) at Berkeley Lab, which computes the information to identify new star events. After the initial observation of the PTF 11kly event, telescopes were used in the Canary Islands (Spain) to identify the emission spectrum of light emitted at various stages of the event. Following this, the Hubble Space Telescope, the Lick Observatory in California, and the Keck Observatory in Hawaii were used to observe the event in greater detail. Although PTF 11kly was initially very faint, it is brightening rapidly. On the day of its discovery, on 22 August 2011, it was 1 million times too dim to be visible to the unaided eye. One day later, on 23 August 2011, it was 10 thousand times too dim. On 24 August 2011, it was 6 times brighter than that. It is expected to be visible with strong binoculars within several weeks of discovery. Importance of type Ia supernovae and SN 2011fe Type Ia supernova events occur when a white dwarf star accretes enough additional matter to exceed the Chandrasekhar limit and collapse, triggering runaway fusion and a supernova explosion. Because this collapse happens at a consistent mass, the resulting explosions have very uniform characteristics, and are used as "standard candles" to measure the distance to their host galaxies. The exact brightness and behavior of a Type Ia supernova depends on the metallicity of its parent star (the fraction of the star composed of elements heavier than hydrogen and helium before its evolution into a white dwarf). Because the PTF 11kly event was detected so early, astronomers can gain a more accurate measurement of its initial composition and of its evolution during the supernova explosion, and so refine their models of Type Ia supernova events (resulting in more precise distance estimates for other Type Ia supernova observations)1. Type Ia supernova standard candles were a key element of the discovery of dark energy and the accelerating expansion of the universe. A better model of type Ia supernova behavior in turn allows models of dark energy to be improved. References ^ a b c d e f Beatty, Kelly (25 August 2011), "Supernova Erupts in Pinwheel Galaxy", Sky & Telescope, retrieved 26 August 2011 External links
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