Comet (C/2011 L4) Panstarrs

Comet (C/2011 L4) Panstarrs

Comet C/2011 L4 (PANSTARRS), is a non-periodic comet discovered in June 2011, that is expected to be visible to the naked eye when it is near perihelion in March 2013. The comet was discovered using the Pan-STARRS telescope located near the summit of Haleakala, on the island of Maui in Hawaii.

Comet C/2011 L4 had an apparent magnitude of 19 when it was discovered in June 2011. By early May 2012, the comet had brightened to magnitude 13.5, and could be seen visually when using a large amateur telescope from a dark site. As of October 2012, the coma (expanding tenuous dust atmosphere) was estimated to be about 120 000 km in diameter. The comet was spotted without optical aid on 7 February 2013 at a magnitude of ~6.

 Comet PANSTARRS will pass closest to Earth on 5 March 2013 at a distance of 1.09 au. It will come to perihelion (closest approach to the Sun) on 10 March 2013. Original estimates predicted the comet would brighten to roughly apparent magnitude 0 (roughly the brightness of Alpha Centauri A or Vega). An estimate in October 2012 predicted the comet might brighten to magnitude -4 (roughly equivalent to Venus). In January 2013 there was a noticeable brightening slowdown that suggests the comet may only brighten to magnitude +1. During February the brightness curve show a further slowdown of Magnitude at perihelion around +2.5/+ 3.0.

Comet C/2011 L4 probably took millions of years to come from the Oort cloud. After leaving the planetary region of the Solar System, the post-perihelion orbital period is estimated to be about 110 000 years.

Date	Altitude at 7:00 pm IST	Azimuth at 7:00 pm IST	expected Magnitude (estimated) taken from MPC*	Comments
March 9	5	260	0.5
March 10	6	262	0.5
March 11	7	264	0.5
March 12	8	267	0.6
March 13	8.5	269	0.7	Thin crescent moon will act as a guide to look for the Comet.It will be about 5 deg below the moon towards 7 o’clock position
March 14	9	272	0.9
March 15	10	274	1.1
March 16	10	277	1.3
March 17	10	279	1.5

* expected magnitude may vary drastically as the Comets are known to behave erratically as far as brightness is concerned.

Magnitude predictions and observation till Feb 20th

Best place to observe:
You should have clear western horizon with no light pollution.  If your skyline in that direction is cluttered with trees, buildings, hills, whatever, chances are they’ll block your view of the comet.