Analysis of past comet apparitions

4P/Faye

2006/07


During autumn 2006 comet 4P/Faye was observable even with small instruments, however starting to fade in December. The following analysis is based on 52 reports by 9 German Comet Section members and 215 international observations. These show different brightness evolutions prior and after perihelion, according to the formulae

pre-perihelion: m = 6.2m + 5×log D + 20.5×log r

post-perihelion: m = 8.5m + 5×log D + 10.5×log r

yielding a maximum brightness of 9.9 mag at the beginning of November 2006.

Total Brightness and Coma diameter

The apparent coma diameter increased continuously since the beginning of the apparition from 0.8' to less than 4' in the first week of November. Thereafter it decreased in a similar manner, however more slowly, reaching 0.7' at the end of March 2007. The absolute coma diameter measured 75.000 km at the beginning of the apparition, increasing to 120.000 km until the first week of November. During the following weeks it decreased, reaching 80.000 km at the end of March 2007. During the whole apparition the coma was significantly condensed, but not as much as the (until November) conspicious false nucleus seemed to indicate. The degree of condensation was DC 3-4 at the start and the end of the apparition, peaking at DC 5 during the second half of October.

The first visual tail reports date from the second half of August, the last sightings were reported in mid-January 2007. The maximum tail lengths reported were in the order of 6' (about 1 mio. km) during the second half of October.

Andreas Kammerer

FGK observations


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