Comet Section        

COMET HIGHLIGHTS FOR AUGUST 2014

2014-August-1

Section Updates

The observing highlight of August should be 6th magnitude comet C/2014 E2 (Jacques). It is one of a number of comets visible with small telescopes and binoculars in the morning sky this month. But the comet highlight of August will be provided by the spacecraft Rosetta as it rendezvous with comet 67P/Churyumov-Gerasimenko.

The Comet Section received 7 magnitude estimates in July of comets C/2014 E2 (Jacques), C/2013 UQ4 (Catalina), C/2013 A1 (Siding Spring), C/2012 X1 (LINEAR) and C/2012 K1 (PANSTARRS). A number of CCD images, including an excellent sequence of C/2013 UQ4 (Catalina) over many nights, was submitted by Gianluca Masi of Italy. Though C/2013 UQ4 only brightened up to 9th magnitude, it displayed a number of jets and tails as it flew within 0.32 AU of Earth in early July.

Gary Kronk has been hard at work digitizing the Comet Section archives. As a result, the Section’s Image Gallery now contains over 600 images and drawings of 110 different comets going back to Ikeya-Seki in 1965. John Sabia has also contributed a number of older images of his that were not in the archive. If you have old (or new) comet images that are not in the Gallery, please consider submitting them.

Evening Comets

C/2012 X1 (LINEAR) [Perihelion on 2014-Feb-21 at 1.60 AU from the Sun]

This comet has been followed by visual observers for ~10 months now. Long past its February perihelion, X1 is currently around 10th magnitude and poorly placed for northern observers as it drifts southward from a declination of -44° in Grus to -50° in Indus. It starts August at around magnitude 10.0-10.5 (2.60 AU from the Sun, 1.70 AU from Earth). By the end of the month it should be around magnitude 11.0 (2.90 AU from the Sun, 2.08 AU from Earth).

Finder charts for C/2012 X1 can be found on the Comet Chasing website. Its ALPO image gallery can be found here.

Morning Comets

C/2014 E2 (Jacques) [Perihelion on 2014-Jul-02 at 0.67 AU from the Sun]

2014’s brightest comet (so far) is C/2014 E2 (Jacques). Discovered by Brazilian astronomer Cristóvão Jacques with the Southern Observatory for Near Earth Asteroid Research (SONEAR) 0.45-m telescope on 2014 March 13, the comet was well followed by Section contributors during March, April and May. After spending June and the first half of July close to the Sun, Jacques once again is visible as a 6th-7th magnitude comet in the morning sky. During July, Jacques’ distance from the Sun increases from 0.90 to 1.35 AU. Fortunately its distance from Earth decreases from 1.05 to 0.56 AU on August 28/29. As a result, Jacques should remain between 6th and 7th magnitude all month long as it moves through Auriga, Perseus, Camelopardalis, Cassiopeia and Cepheus. The following plot contains visual magnitude estimates submitted to the Section by Salvador Aguirre and Carl Hergenrother.

Recent ALPO images and observations of C/2014 E2 (Jacques) can be found in the Comet Section Image Gallery and Magnitude Database. Finder charts can be found on the Comet Chasing website.

C/2013 A1 (Siding Spring) [Perihelion on 2014-Oct-25 at 1.40 AU from the Sun]

We are definitely on the wrong planet for this comet! Siding Spring will pass within ~132,000 km of Mars (just 1/3rd the Earth-Moon distance) on October 19. For Martians (including the armada of spacecraft at Mars), the comet will be a brilliant object of negative magnitude. If the nucleus is larger than a few 100 meters, it should be resolvable by the Mars Reconnaissance Orbiter’s HIRISE camera. Here on Earth, the comet starts August around magnitude 10.2 (1.85 AU from the Sun, 1.46 AU from Earth) and should brighten to magnitude 8.5 to 9.0 by Sep 1 (1.60 AU from the Sun, 0.90 AU from Earth). Unfortunately for northern observers (but good for southern observers), the comet starts the month far south (-39° declination) and only heads deeper south as it traverses the constellations of Eridanus, Horologium, Hydrus, and Tucana. Northern observers get a chance to observe it in mid-October as it nears its date with Mars.

Recent ALPO images and observations of C/2013 A1 (Siding Spring) can be found in the Comet Section Image Gallery and MagnitudeDatabase. Finder charts can be found on the Comet Chasing website.

C/2013 V5 (Oukaimeden) [Perihelion on 2014-Sep-28 at 0.63 AU from the Sun]

Michel Ory of Switzerland discovered this comet with an Oukaimeden Observatory telescope near Marrakesh, Morocco. Currently around magnitude 10.5 (1.31 AU from the Sun, 1.92 Au fromEarth), this comet may rapidly brighten as it gets closer to both the Sun and Earth. By the end of August, the comet may be a 7th magnitude object (0.85 AU from the Sun, 0.85 AU from Earth). It will be interesting to watch the development of this comet. Its orbit suggests it is a new comet on its first passage through the inner Solar System. Such new and relatively faint comets can be prone to disintegrating. We’ll have to watch and see. This month it is a morning object moving against the stars of Orion and Monoceros.

Recent ALPO images and observations of C/2013 V5 (Oukaimeden) can be found in the Comet Section Image Gallery and MagnitudeDatabase. Finder charts can be found on the Comet Chasing website.

Other Comets of Interest

C/2012 K1 (PANSTARRS) [Perihelion on 2014-Aug-27 at 1.05 AU from the Sun]

Comet PANSTARRS was well observed by Section contributors from early March to early July as it brightened from magnitude 11.5 to 7.9. Since early July it has been too close to the Sun to observe. This will remain the case till September when it will become visible in the morning sky as a 7th-8th magnitude object. Luckily the comet is now visible in the SOHO C3 field of view through mid-month (though at 7th magnitude or so it is a faint object for SOHO).

67P/Churyumov-Gerasimenko [Perihelion on 2015-Aug-13 at 1.24 AU from the Sun]

The big comet news of the month is the arrival of the European Rosetta spacecraft at short-period comet 67P/Churyumov-Gerasimenko. Rosetta will be the first spacecraft to orbit a comet’s nucleus. The previous missions were quick flybys. Already Rosetta has returned images of the nucleus showing a dual “contact binary” structure. The images and results from Rosetta will only get better as the spacecraft gets closer to the comet and the comet gets closer to the Sun.  The comet is currently ~20th magnitude in Sagittarius and will brighten to ~11th magnitude by the summer of 2015.

As always, the Comet Section is happy to receive all comet observations, whether images, drawings or magnitude estimates.

- Carl Hergenrother (ALPO Comet Section Coordinator)