On July 12, 2013 Krisztian Sarneczky recovered comet P/1998 U3 (Jäger) with the 0.60m Schmidt telescope at Konkoly Observatory. Positioned in the southern part of the constellation Perseus comet P/2013 N1 (Jäger) showed an 8" coma of total magnitude 17.5 mag and a 15" tail in p.a. 270° (CBET 3581). Thus it was 2 mag fainter than the brightness parameters derived in its apparition of 1998/99 would suggest. Maybe the comet was actually brighter than reported or it has not yet lived up to the activity level of 1998/99. The comet will pass perihelion on its 15.20 year orbit in mid-March 2014 and should reach a maximum brightness of 10.5 mag – nearly identical to its peak brightness in 1998/99. It will be situated in the southeastern part of Auriga, being observable during the whole night. In the meantime it was assigned the permanent designation 290P/Jäger (MPEC 2013-Q14).

Comet 290P/Jäger was a difficult object visually in its second apparition. 31 reports by 6 members of the German Comet Section and 45 international observations indicate a uniform brightness evolution which can be represented by the following formula:

This yields a maximum brightness of 12.4 mag during the second half of January 2014. The scatter in the estimates is significantly larger than in the apparition 1998/99, when it reached a maximum brightness of 10.5 mag. Comparing both apparitions the activity parameters are very similar, but in 1998/99 the absolute magnitude was 2 mag brighter. In 1998/99 it was the first time that this comet came this close to the Sun. Thus it is very likely that it released a large amount of volatile components during this apparition which could not be supplied by the nucleus in 2013/14.

Total Brightness and Coma Diameter

The apparent coma diameter increased from 0.4' in mid-October 2013 to a maximum of 1.3' in January/February 2014. Thereafter it decreased more slowly, measuring still 0.8' at the start of May. In absolute dimensions the coma increased from 40.000 km at the start of the apparition to 80.000 km in early January. This diameter remained constant until the end of the apparition (in 1998/99 the coma diameter reached 3.5' = 190.000 km). The coma was rather diffuse. At the start of the apparition the degree of condensation was estimated to be DC 2-3, increasing to DC 3-4 until mid-January. This value remained constant thereafter. The short tail (1-2') was visually very difficult and thus the domain of the photographers. In contrast in 1998/99 it reached 6' and could be well seen visually.

Andreas Kammerer

FGK observations