Comet C/2011 L4 (PANSTARRS) will come within 1.1 AU of the Earth (1.1 times as distant as the Sun) on Tuesday 5 March 2013. The comet is visible with binoculars in the Southern Hemisphere, and should become visible in the Northern Hemisphere from 7 March, and possibly become bright enough to be seen with the naked eye. The comet is already closer to the Sun than the Earth, and indeed Venus, but not close to us and traveling at a very high angle to the plane of the Solar System. It will reach its perihelion (closest point to the Sun) on 10 March, when it will potentially be at its brightest (though comets are notoriously hard to predict), and should remain visible for the rest of the Month. It will be easiest to locate on 12-14 March, when it is closest to the Moon, though it might be hard to see at this time due to the Moon's brightness.
The passage of comet C/2011 L4 (PANSTARRS) in February-April 2013. Eagle Eye on the Sky.
Comet C/2011 L4 (PANSTARS) is thought to be a non-periodic comet on its first visit to the inner Solar System, having been disturbed from its previous orbit within the Oort Cloud some time within the last few million years. It is likely that it will revisit the inner Solar System every 110 000 years from now on. It was discovered in June 2011 by the Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) array of telescopes on Haleakala, Hawaii. It will move away from the (Northern Hemisphere) horizon during April, becoming fainter and disappearing towards the North Pole as it moves away from the Sun. It will not be visible from the Southern Hemisphere during this time.
See also 99942 Apophis to fly by the Earth, The Earth approaches its perihelion, Possible second meteor shower to coincide with the Geminids, Asteroid 4179 Toutatis/1989 AC to fly past the Earth and The Geminid Meteors.
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