121P/Shoemaker-Holt 2

Japanese version
Home page
Updated on August 28, 2020


* Profile

The light curve is extremely strange; it becomes brightest about 145 days after the perihelion passage. It was discovered in 1989 when it has already passed a half year after the perihelion passage, that is because this peculiarity.

Kazuo Kinoshita's calculation revealed that it passed close by Jupiter in 1984 and the perihelion distance reduced from 3.25 A.U. down to 2.65 A.U. It became closest to the sun during several hundred years, and it was discovered.

The maximum brightness has been fading by 1 mag in every appearance during last three appearances in 1988, 1996 and 2004. But the strange light curve, the comet becomes brightest about 145 days after the perihelion passage, did not change.

Kazuo Kinoshita's calculation revealed that it will pass close by Jupiter again in 2008, and the perihelion distance increases drastically up to 3.75 A.U. So it will be extremely faint, fainter than 19 mag at best, after the next return in 2013.

In spite of its asymmetric light curve, no non-gravitational effect is found in Kazuo Kinoshita's calculation.

* Returns and Appearances

!Discovered *Appeared -Not observed #Appeared before discovery +Not observed before discovery .Returns in the future
* 121P
2023 June 28
* 121P
2013 Sept. 8
* 121P
2004 Sept. 1
* 121P/1995 Q3
1996 Aug. 20
! 121P/1989 E2
1988 Aug. 7


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/0121p.htm).


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