Comet ISON passed just 1.2 million kilometres from the Sun’s visible surface on Thanksgiving Day. A small chunk of ISON’s nucleus, along
Images: ESA/SOHO
with a lot of dust was seen after the comet’s encounter with the Sun, but within days had faded completely.
reflect sunlight making it visible
in telescopes. As the comet gets
closer to the Sun more of it’s
constituent parts heat up creating
more ejaculate from the coma
resulting in longer tails and also
brighter surfaces. The theory was
that as the comet approached the
Sun it would brighten dramatically,
making it so bright that it would
be visible during daylight. ISON
confounded
the
experts
by
remaining dimmer than anticipated
and not becoming the ‘Comet of
the Century’ as predicted. Then all
of a sudden there was a dramatic
brightening and it was speculated
that ISON could live up to its name.
The dramatic moments came on
November 28th when the comet
Comet ISON viewed from Earth as it streaked through space on Nov. 13, 2013.
Photo: Peter Carson http://www.astromania.co.uk
approached perihelion. Perihelion
is when the comet slingshots
around the sun and starts on its
way back out again. As the comet
approached the Sun some of the
instruments observing it saw what
looked like an explosion as ISON
was diving towards the closest
approach. This left experts thinking
that the comet had broken up and
vaporised as it was affected by the
extreme heat of the approach. This
seemed to be confirmed when the
comet did not appear on the SDO
instrument and even ESO scientists
were confirming that ISON had
gone.
Shortly after the ESO announcement the comet remains could be
seen on the LASCO C2 instrument
looking comet shaped, but much
fainter than expected. However at
12:30 UT on the 29th the LASCO C3
imagery is showing what looks like a
comet, certainly more than debris
heading on the expected trajectory
of ISON. Whilst not as large or bright
as originally expected it was quite
faint compared to the comet preperihelion, but definitely there. This
however faded to nothing a few
days later, proving that comets
are fickle, unpredictable celestial
bodies.
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