[meteorite-list] Newfound Comet Could Look Spectacular in 2013 (C/2012 S1 ISON)

[Ron Baalke]

http://www.space.com/17762-newfound-comet-dazzling-2013-display-c2012s1.html 

Newfound Comet Could Look Spectacular in 2013
by Joe Rao
space.com
25 September 2012 

A newly discovered comet has the potential to put on a dazzling celestial 
display late next year, when it will be so bright you may be able to see it 
briefly in the daytime sky.

The discovery of the object named Comet ISON was announced 
Monday (Sept. 24) by Russians Vitali Nevski and Artyom Novichonok, who 
detected it in photographs taken three days earlier using a 15.7-inch 
(0.4-meter) reflecting telescope of the International Scientific Optical 
Network (ISON), near Kislovodsk. The new comet is officially known as 
C/2012 S1.

When first sighted, Comet ISON was 625 million miles (1 billion 
kilometers) from Earth and 584 million miles (939 million km) from the 
sun, in the dim constellation of Cancer. It was shining at magnitude 18.8 
on the reverse scale used by astronomers to measure the brightness of 
sky objects (the lower the number, the brighter the object). That makes 
the comet currently about 100,000 times fainter than the dimmest star 
that can be seen with the unaided eye.

But at its perihelion (its closest point to the sun), due on Nov. 28, 2013, 
the comet will come within 800,000 miles (1.2 million km) of the sun's 
surface and could evolve into a dazzling object - possibly bright enough to 
be visible for a short time in broad daylight.  

The fact that the orbits are so similar seems to suggest Comet ISON and the 
Great Comet of 1680 could related or perhaps even the same object.

Comet ISON will be barely visible to the unaided eye when it is in the 
predawn night sky, positioned against the stars of Leo in October 2013.

On Oct. 16 it will be passing very near both Mars and the bright star 
Regulus - both can be used as benchmarks to sighting the comet. In November, 
it could be as bright as third-magnitude when it passes very close to the 
bright first-magnitude star Spica in 
Virgo. 

The few days surrounding the comet's closest approach to the sun on Nov. 28, 
2013, are likely to be most interesting. It will whirl rapidly around the sun 
in a hairpin-like curve and perhaps becomes a dazzlingly bright (negative-
magnitude) object.  

The comet will then whirl north after perihelion and become visible during 
December both in the evening sky after sunset and in the morning sky before 
sunrise. Just how bright it will be and how long the tail may get during this 
time frame is anybody's guess, but there is hope that it could evolve into a 
memorable celestial showpiece.

And in case you haven't checked your 2013 calendar, Nov. 28 is already a 
special day for those living in the United States: It is the Thanksgiving Day 
holiday.

Which leads to the question: Will Comet ISON be a dazzler, or a turkey?