C/2012 S1 ISON

Closest to Earth on 21 November 2013 at 0.85AU
Closest to Sun on 28 November 2013 at 0.012AU
Maximum magnitude -2 prior to perihelion

 


C/2012 S1 ISON
Left: 2013 Nov 03.78UT
Middle: 2013 Nov 13.75UT
Canon 60Da and 300mm EF zoom lens cropped. 4x1min exposures.
Right: 2013 Nov 18.75UT. 4x30s

Comet ISON failed to survive Perihelion on the morning of November 29, Australian time, when only 2 million kms from the Sun.
At discovery in September 2012, ISON's brightness at the time suggested it would become the Great Northern Comet of December 2013.
By February 2013, ISON had other ideas, when activity virtually came to a standstill.
This activity well out from the Sun was driven by highly volatile gas such as CO2, which eventually depleted, indicating that the nucleus was quite small.
This type of behaviour is typical of dynamically new comets that have never been exposed to Sunlight before.
ISON's brightness since then was more representative of a reflecting body.
This behaviour made ISON a high risk for disintegration and it eventually became the fizzle of the century!