COMET HIGHLIGHTS for DECEMBER 2013
2013-Dec-1
Comet Spotlight
November saw no less than 5 comets visible in small aperture equipment. December looks to be a quieter month as 2P/Encke is too close to the Sun for observation and C/2012 S1 (ISON) has, like Icarus, succumbed to its close pass of the Sun. Barring any surprises, the best comet of December should be border-line naked eye object C/2013 R1 (Lovejoy).
Outbound Comets
C/2012 S1 (ISON) [T = 2013 Nov 28, q = 0.012 AU]
I won’t spend too much time on ISON as the past few days have seen lots of ISON updates. In short, the comet appears to be nothing more than an ever expanding cloud of dust. Over the next few mornings, observers will be able to pick the comet up in a dark sky. Its current brightness is uncertain but it is unlikely to be brighter than 6th magnitude. It will be interesting to see how long the remains of ISON will be followed.
Inbound Comets
C/2013 R1 (Lovejoy) [T = 2013 Dec 22, q = 0.81 AU]
Discovered back in September by Australian amateur Terry Lovejoy, C/2013 R1 (Lovejoy) has developed into a wonderful comet. While ISON got all of the press, Lovejoy has turned out to be just as photogenic and visually pleasing. Currently around magnitude 4.5 to 5.0, the comet is also the owner of a long 2+ degree tail. Perihelion occurs on December 22 at 0.81 AU from the Sun. After passing within 0.40 AU of Earth in mid-November, the comet starts the month 0.49 AU and ends the month 1.06 AU from Earth. The increasing geocentric distance will counter the decreasing heliocentric distance and result in a comet that should stay fairly stable in brightness. Lovejoy is a morning object and will spend December moving through the constellations of Bootes and Hercules.
In outburst?
C/2012 X1 (LINEAR) [T = 2014 Feb 21, q = 1.60 AU] and C/2013 V3 (Nevski) [T = 2014 Oct 29, q = 1.39 AU]
Both comets LINEAR and Nevski experienced 5+ magnitude outbursts. Long-period LINEAR still has ~3 months to go before reaching perihelion while Nevski is just over a month past perihelion. Nevski is also a Halley-type comet with an orbital period of ~43 years.
Both comets are morning objects and have faded to fainter than 10th magnitude at this time. Whether either comet experiences another major outburst is unknown but they are definitely two comets to keep an eye on. LINEAR moves from Bootes into Serpens Caput while Nevski moves from Leo into Leo Minor.
The Section is always collecting observations (both visual and CCD) and magnitude estimates for all comets. An image gallery has been set up and now contains images of 40 different comets. Over the next few weeks, I will be rolling out dedicated pages to some of the brighter comets. These pages will be updated as needed with new observations and lightcurves.
All ephemerides/positions for the above comets and all other comets can be generated at the Minor Planet Center and JPL/Horizons websites.
- Carl Hergenrother (Comet Section Acting Co-Coordinator)
