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Updated on July 5, 2017


* Profile

Bright short periodic comet, however, it has been lost since apparitions twice in 1975 and 1986.

The light curve is almost along the 40 log r formula. It brightens rapidly just before the perihelion passage, and fades out rapidly soon after the perihelion passage.

Because the perihelion distance is 1.1 A.U., it passes near by the earth and becomes very bright if it passes the perihelion from autumn to winter. On the other hand, it is extremely hard to observe due to the bad condition if it passes the perihelion from spring to summer. The condition was good in 1975 and 1986, but it was missed in 1997 due to the bad condition. It will return in good condition again in 2008.

In 1986, it became brighter than at the discovery in 1975 by 2 mag. In 2008, it has not been recovered yet in August. This implies the comet can become much fainter than before, by 2 mag than at the discovery, or by 4 mag than 1986.

Kazuo Kinoshita's calculation revealed that the orbit does not change so much from early 20th century to mid 21st century.

* Returns and Appearances

!Discovered *Appeared -Not observed #Appeared before discovery +Not observed before discovery .Returns in the future
2020 July 29
2008 Dec. 16
1997 Apr. 17
* 85D/1985 T2
1986 Jan. 16
! 85D/1975 A1
1975 Jan. 5


The perihelion dates in the past appearances are printed on Catalog of Cometary Orbits 1996.
Information on the discovery and historical highlights are available at General Comet Info (Gary W. Kronk).
The past and future orbital elements calculated by Kazuo Kinoshita (http://www9.ocn.ne.jp/~comet/pcmtn/0085p.htm).


Copyright(C) Seiichi Yoshida (comet@aerith.net). All rights reserved.