108P/Ciffréo

Lore & Background

The comet was discovered by Jacqueline Ciffréo on 8 November 1985 using a 0.9 m Schmidt camera at Caussols, appearing as a diffuse object with an apparent magnitude of 10. The following day, H. Kosai from the Tokyo Observatory noted a faint tail about 1.5 arcminutes long. An elliptical orbit was published by Daniel W. E. Green on 18 November, with an estimated orbital period of 7.81 years and perihelion on 28 October 1985 at 1.72 AU; later observations refined perihelion to 30 October and the orbital period to 7.22 years. In December 1985, a detached coma or tail was detected 6 arcseconds from the nucleus, extending 20 arcseconds to the north-east, with a visual magnitude of 12.5.

The comet was recovered on 24 September 1992 by J. V. Scotti with the Spacewatch telescope, passing perihelion on 23 January 1993. Subsequent perihelia occurred in April 2000, with observations in November and December 1999 and November and December 2000. During the 2014 and 2021 apparitions, the comet again featured a detached coma similar to that observed in 1985. The peculiar morphology was initially attributed to a possible fragmentation event, but further observations indicate it is most probably an artifact of the turnaround of particles ejected sunward and repelled by sunlight.

The comet is at a 5:3 orbital resonance with Jupiter, allowing frequent planetary encounters. Between 1900 and 2183, its closest approach to Jupiter will occur on 18 December 2076 at a distance of 0.28 AU. Initial orbital calculations suggested it was a recently captured object, but follow-up studies in 1990 revealed its dynamical behavior corresponds to a relatively 'aged' object, having been on its current orbit for at least 1,500 revolutions since at least 12,000 BC.

Reader's Guide

108P/Ciffréo holds significance as the sole comet discovered by French astronomer Jacqueline Ciffréo, marking a notable individual contribution to cometary astronomy. Its peculiar double morphology—a nucleus accompanied by a comoving, detached, diffuse tail—has drawn observational attention since its discovery. The article describes this feature as probably a perspective artifact of particles ejected sunwards and then repelled by solar wind, rather than a fragmentation event, though the latter was initially considered. This interpretation underscores the complexity of cometary outgassing and solar wind interactions. The comet's orbital dynamics are also noteworthy: it resides in a 5:3 orbital resonance with Jupiter, leading to frequent close encounters, with a predicted approach to Jupiter on 18 December 2076 at 0.28 AU. Its dynamical history was revised from a recently captured object to an 'aged' one, having occupied its current orbit for at least 1,500 revolutions since at least 12,000 BC, providing insight into the long-term evolution of Jupiter-family comets. The comet's recovery in 1992 and subsequent apparitions in 2000, 2014, and 2021 have allowed continued study of its persistent detached coma, reinforcing the artifact hypothesis.

Did You Know?

• The comet has a peculiar double morphology, with a detached, comoving tail likely caused by sunward-ejected particles repelled by solar wind.
• It is in a 5:3 orbital resonance with Jupiter, with a closest approach of 0.28 AU on 18 December 2076.
• Initial orbital calculations suggested it was recently captured, but later studies showed it has been on its current orbit for at least 1,500 revolutions since 12,000 BC.