Comet hunters have not had it great over the last few years with just a couple of moderate performers mixed in with many faint examples but no real showstoppers since 2007. That was the year when the daytime comet C/2006 P1 McNaught briefly burst onto the scene, reaching an astonishing magnitude of -5. Later that year periodic comet 17P/Holmes brightened substantially and was easily visible to the naked eye as a 3rd magnitude fuzzy star in Perseus, but since then there has been little on offer.
Now two comets have caused a stir for different reasons. Although neither is a showstopper, one showed much potential but faded while the other is almost certain to put on a nice but moderate show.
Elenin Boom and Bust
A lot of early excitement was provided by comet C/2010 X1 Elenin. It was discovered on the 10th December 2010 by Russian amateur astronomer Leonid Elenin and early press speculated than Elenin may put on a good naked eye show around October 2011. At this time it should approach to within 35 million kilometers of Earth but unfortunately the latest observations suggest that the comet will be a complete washout. Elenin faded dramatically after a solar flare on the 20th August and now appears to be disintegrating and unlikely to survive for much longer.
However, all is not lost as there is another comet in the night sky that has until now attracted much less attention than Elenin but will almost certainly produce a fine performance for many months to come. The comet in question is C/2009 P1 Garradd. Gordon Garradd discovered the comet on the 13th August 2009. Like many comet discoveries these days, Garradd was searching for near-Earth objects using the Siding Spring Observatory near Coonabarabran in Australia when he captured the magnitude 17.5 comet. Since then Comet Garradd has brightened steadily and from July 2011 has been a nice target, shining at magnitude 7 and visible in telescopes of all sizes.
As comets go Garradd is unusually large and quite active. Unfortunately, it never gets very close to either the Sun or the Earth. At perihelion on the 23rd December 2011, it is 1.55 AU (230 million kilometers or 144 million miles) from the Sun. Closest approach to Earth is not much better. When this happens on the 5th March, Garradd will still be about 1.27 AU (188 million kilometers or 118 million miles) away.
At these sorts of distances, Comet Garradd is about as far away as Mars, which is hardly close for a comet. It’s a real shame it does not approach much nearer as it would be a spectacular sight, easily visible to the naked eye and probably rank as one of the great comets of recent times. Nevertheless the comet will be a steady performer between September 2011 and March 2012 peaking at around magnitude 5.8 in February 2012. The finder chart and data table below show the path of Garradd from the end of September 2011 to the beginning of February 2012. During this time the comet moves its way through Hercules.
It is best observable from mid-northern latitudes appearing in the evening sky until year’s end. In the New Year the comet climbs high in the early morning sky, passing on the eastern side of the famous Hercules "Keystone" asterism before making a close approach, on the 3rd February, to within only 0.5 degrees of globular cluster M92. A time to mark your diary and get your camera out!!
Garradd then continues on sailing past the head of Draco before reaching its highest point in the sky in Ursa Minor in March. Between now and then we will of course be following and reporting on the progress of Garradd as it continues on its path through the Solar System. Watch this space!