Analysis of past comet apparitions

103P/Hartley 2

1997/98


The Fachgruppe Kometen received 74 observations of 10 members of comet 103P/Hartley 2. For the analysis an additional 300 international observations were integrated. Similar to the apparition in 1990 comet Hartley 2 again showed a very asymmetric brigthness evolution, which can be well described by the formulae

pre-perihelion: m = 8.5m + 5×log D + 19.8×log r

post-perihelion: m = 8.5m + 5×log D + 8.0×log r

This gives the maximum brigthness as 8.2 mag.

Due to the fact, that the distance earth - comet changed only marginally during severat months, the evolution of the apparent and absolute coma diameter is nearly identical. At the start of this apparition a coma diameter of 1' (50.000 km) was reported. It reached a maximum of 7' (280.000 km) at the end of 1997, but since then dropped to 2' (125.000 km) in April. Within the same time interval, the degree of condensation increased from DC 1 to DC 5, but since then dropped to DC 3. A visually visible tail was only reported at the end of 1997 and the start of 1998, with a maximum length of about 0.1° (200.000 km).

Total Brightness and Coma Diameter

Andreas Kammerer

Observations


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