27 observations of 6 section members reached us of comet 69P/Taylor. Adding 100 internatonal observations shows a clear distinction of the brightness evolution prior and after perihelion as indicated below:
t<+85d: m = 10.7m + 5×log D + 0.04×|t-T-85d| t>+85d: m = 11.2m + 5×log D + 0.01×|t-T-85d|
Whereas the apparent coma diameter showed its maximum of 2' at the end of February the absolute diameter increased continually during the appearance from 50.000 km to 120.000 km. At the start, the coma was only slightly condensed (DC 1-2), but at the end of February the degree of condensation had reached DC 5. This however was only of short duration and in April the coma's condensation had decreased to DC 2-3.
Comet Taylor was forced on an orbit very similar to its present one due to a very near Jupiter encounter (0.06 AU) in September 1807. Another encounter in June 1925 then decreased the perihelion distance to 1.6 AU. Further Jupiter encounters in June 2008 (0.16 AU) and April 2091 will increase the perihelion again towards 2.7 AU (AFZ 585).
Brightness evolution and coma diameter
Andreas Kammerer
