An asteroidal object discovered on May 4, 2011 near the border of the constellations Sextans/Crater by the LINEAR team showed cometary morphology in the course of detailled observations. Comet C/2011 J2 (LINEAR) showed a 7" coma of total magnitude 20 and a 10" tail in p.a. 73°. It will pass perihelion not until the end of December 2013, when it could reach 14 mag (IAUC 9208). It should be brighter than 16 mag during the years 2013/14, when it will be comfortably placed for mid-European observers, moving through the constellations Ursa Major, Draco, Ursa Minor, Cepheus, Cassiopeia, Andromeda into Pegasus. To derive the evolution of this comet I could only use 55 observations. This small data base, combined with the small variance in solar distance makes the results uncertain. The brightness can be best represented by the formula m = 5.3 mag + 5×log D + 10×log r, yielding a maximum brightness of 13.1 mag in mid-December 2013. The diameter of the moderately condensed (DC 4 to 4-5) coma reached a maximum of 1.0' (150.000 km).
Total Brightness and Coma Diameter
On Aug. 27, 2014 an italian science team discovered a component B, 7.5" from the primary and 1.5 mag fainter than this. No additional fragments could be detected brighter than 23 mag. Simulations by Z. Sekanina yields Jan. 10, 2014 (+/- 10 days) as the date of the very gentle separation of the fragment from the primary (CBET 3979/86).
--------------------
On May 27, 2012 R.H. McNaught discovered an 18.5 mag comet near the border of the constellations Tucana/Indus with the 0.5m-Uppsala-Telescope at Siding Spring. Comet C/2012 K6 (McNaught) showed a 10" coma, which was elongated towards NW. The comet will pass its perihelion in May 2013, expected to reach magnitude 15.5. However, it will then be positioned in the far-southern sky, invisible for mid-European observers (CBET 3131 / MPEC 2012-L04). According to the very small number of published observations the comet peaked at magnitude 14.5-15.0 in spring 2013. The extremely diffuse (DC 1) coma measured only 0.5'.
--------------------
On Sep. 27, 2012 the PANSTARRS project discovered a 19.5 mag comet in the constellation Draco. Comet C/2012 S3 (PANSTARRS) showed a faint 9" coma. It will pass perihelion at the end of August 2013, expected to reach magnitude 14.5 (CBET 3244 / MPEC 2012-V101). During the most interesting weeks (July and August 2013) it moves from the constellation Equuleus into Sagittarius, where it will disappear for mid-European observers above the southwestern evening horizon. No visual observation came to my knowledge. The maximum brightness published by CCD-observers ranged between 14.5 and 15.0 mag.
--------------------
On Nov. 5, 2012 the LINEAR team discovered a 19.0 mag asteroidal object in the constellation Cepheus. During the following days several observers remarked its cometary nature. Comet C/2012 V2 (LINEAR) showed a condensed 23" coma of magnitude 17.0 with a central condensation and a faint 20" tail in p.a. 90°. It will pass perihelion on its 2500 year orbit in August 2013, expected to reach magnitude 12 (CBET 3290 / MPEC 2012-V101). However, mid-European observers can follow it only until the end of April 2013, when it will only have reached magnitude 14. Prior to its disappearance in the mid-European twilight at the end of April 2013 the brightness of this comet evolved according to the parameters m0=9.0 mag / n=4, derived from the brightness at discovery. However, the comet surprised observers in the Southern hemisphere, when it reappeared in mid-August 2013. At that time it was an object of magnitude 9.0, instead of the predicted 12.5 mag. The evolution after the reappearance is documented by 70 international observations. The brightness evolved according to the parameters m0=5.0 mag / n=5, yielding a maximum brightness of 8.7 mag at the end of August / beginning of September. Thus the comet must have experienced a high state of activity near its conjunction with the Sun, which leveled-off during the following weeks. The coma diameter measured short of 3.5' (325.000 km) for several weeks. Starting in mid-September it began to shrink, measuring 1.3' (150.000 km) in mid-December. Until the start of November it was well-condensed (DC 5). Thereafter it started getting more and more diffuse with the degree of condensation in the order of DC 2-3 in mid-December. No visual tail sightings have been reported.
Total Brightness and Coma Diameter
--------------------
On Mar. 10, 2013 Masayuki Iwamoto discovered a diffuse, 13 mag comet with his digital camera plus a 100mm-tele in the constellation Aquila, near the border to Aquarius. Comet C/2013 E2 (Iwamoto) showed a 44" coma with a highly condensed central condensation. It passed perihelion during the first week of March, peaking in brightness right on discovery date (CBET 3439 / MPEC 2013-G31). The very small number of observations and images indicate a very diffuse comet with a coma diameter of about 1-1.5'. Very few observations have been published. They indicate that the comet was 2 mag brighter than predicted, implying that the discovery brightness had been understimated in a similar manner. The brightness peaked at about 11.0 mag, the diameter of the rather diffuse (DC 2) coma diameter at about 2'. The orbital period was derived to be about 3.500 years (MPEC 2013-L39).
--------------------
On images taken in the course of the CATALINA Sky Survey on Apr. 13, 2013 in northern Bootes an asteroidal object was discovered which showed cometary morphology at closer inspection. Comet C/2013 G5 (Catalina) showed a 12" coma of total magnitude 18.5 and a 30" tail in p.a. 250°. It will pass perihelion in the first days of September and could then reach magnitude 11.5 (CBET 3474). Mid-European observers can follow the comet in the evening sky until perihelion, moving through the constellations Bootes, Virgo and Libra. Visual observers could not succeed in detecting the comet, because the comet began to disintegrate in late June, when it had only reached magnitude 17.
--------------------
On May 8, 2013 R.H. McNaught discovered a 17.5 mag comet with the 0.5m-Uppsala-telescope on Siding Spring in the constellation Capricornus. Comet P/2013 J2 (McNaught) showed a 20" tail in p.a. 240°; the coma was slightly larger than the adjacent stars. It orbits the sun with a period of 15.5 years and will pass perihelion at the end of August 2013, when it is expected to be of magnitude 16.0 (CBET 3510 / MPEC 2013-L39). Actually the comet became three magnitudes brighter than expected in summer 2013. Published observations report magnitude 13.0 and a diameter of the moderately condensed (DC 3) coma of about 0.7'.
--------------------
On July 8, 2013 Gennady Borisov discovered a comet with the 0.2m-astrograph on Sternberg Observatory in the constellation Auriga. He estimated the coma diameter of comet C/2013 N4 (Borisov) to be only 20", having a total magnitude of 16 mag. However, other observers reported a coma diameter of about 1.5' with a total magnitude of 13.5 mag. The comet passed perihelion on its orbit with a period of about 335 years at the end of August when it was situated on the far side of the sun. Thus it was not expected to brighten further by more then a half magnitude (CBET 3584 / MPEC 2013-R59). The few published observations are discordant, but seem to indicate a brightness of about 11.0 mag and a coma diameter of about 3' in mid-August 2013. Surprisingly observations in October still reported magnitudes of about 11 mag, instead of the predicted 12.5 mag. In mid-November 2013 it was of magnitude 14.0, in early January 2014 of magnitude 15.5, showing a coma diameter of 1'.
--------------------
The periodic comet 63P/Wild (P=13.19a) will pass perihelion at the beginning of April 2013, expected to reach 14.0 mag. In spring it will be situated in the western part of Leo, moving southward. It should therefore be an evening target for owners of larger instruments. Mid-European observers can follow it until the start of June, when it will disappear above the western horizon. For the analysis of the current apparition 4 observations by 2 members of the German Comet Section and 22 international observations could be used. These show a large range in the brightness estimates which can be described reasonably well with the parameters m0=12.0 mag / n=0, yielding a maximum brightness of 12.0 mag in March 2013. However, this can be assumed up to 0.5 mag brighter without problems. The apparent coma diameter was quite constant at 1.3', which corresponds to an increase in the absolute diameter from 60.000 to 100.000 km. The coma was only marginally condensed (DC 3), becoming even more diffuse near the end (DC 2).
Total Brightness and Coma Diameter
--------------------
Images taken with the PANSTARRS-1-telescope on July 4, 2013 showed a 20 mag comet in the constellation Sagittarius. Shortly thereafter G.V. Williams noted that this comet was identical with the asteroidal object 2003 WY25, which was discovered in 2003 by the Catalina project. Images taken by H. Sato with a 0.5m telescope showed a strongly condensed, 30" coma of total magnitude 17.5 and a stellar central condensation of magnitude 19.5. In 2003 Micheli had already made the suggestion that 2003 WY25 could be identical with the long lost comet P/1819 IV (Blanpain), which was confirmed by the recent observations. The comet, now permanently designated 289P/Blanpain, will reach perihelion of its orbit with a period of 5.32 years in late August 2014 (CBET 3574). At that time it will be an object in the morning sky, attaining only altitudes below 20° for mid-European observers. In the case of a standard evolution (n=4) it may peak at 11 mag. However, since this comet seems to be mostly inactive it may brighten much slower, peaking at only 15 mag in the case of n=2. This comet was last observed on July 17, 2013 – only 13 days after the recovery. Thus it has to be assumed that the recovery was possible due to a short-lived outburst and that it is again inactive since the second half of July 2013.
Andreas Kammerer
