It had been lost for about 200 years since its discovery in 1819 until
recovered in 2003.
The absolute magnitude in 1819 is estimated as 8.5 mag. Probably it
was visible as bright as 5-8 mag. However, this brightness was
exceptional in unusual great outburst. Usually, little cometary
activity is observed and it looks almost asteroidal with an absolute
magnitude of 20.5 mag.
Kenji Muraoka's calculation revealed that the orbit is wavering as
the perihelion distance between 0.88 A.U. and 1.04 A.U., and the
period between 5.1 years and 5.5 years.
It is usually extremely faint, fainter than 22 mag. But if it passes
the perihelion between late November and late December, it passes
near by the earth and becomes bright. However, due to a little
difference of the perihelion distance, the apparent brightness changes
When the perihelion distance is smaller than 1.0 A.U., the comet
becomes invisible at the approach to the earth because it enters
between the sun and the earth. Therefore, it brightens up to only 18
When the perihelion distance is larger than 1.0 A.U., it becomes very
bright if it passes the perihelion on a special day in early
December. However, only if the perihelion passage shifts by a several
days, the maximum brightness fades by several magnitudes.
During about 300 years from 1819 to 2109, the comet becomes brighter
than 18 mag only four times.
|Perihelion Passage||Maximum Brightness||Nearest Distance|
|2003||Dec. 11||14.4 mag||0.025 A.U.|
|2035||Nov. 20||17.4 mag||0.088 A.U.|
|2019||Dec. 20||17.6 mag||0.089 A.U.|
|2067||Nov. 26||17.7 mag||0.102 A.U.|
It was recovered in 2003 because every condition became
extraordinarily excellent during recent 300 years. But it will never
be brighter than 17 mag again during next about 100 years until 2109.
For about 200 years since its discovery, the condition had been bad in
all returns. It had never been brighter than 18 mag. So it had been
missed until 2003.
If the great outburst like in 1819 happens again, it can be a naked
eye object in good condition, or at least 10 mag even in bad