Comets observed in early times, which were later found to be observations of numbered periodic comets, are marked with [periodic comet number]/[comet name]. For instance, X/-239 K1 was an appearance of Halley's comet in 239 BC, and as such is written as 1P/-239 K1.
The Kracht-group comet C/2008 R7 is likely to be a return of one of the members of Sept. 2002. R. Kracht himself suggests identity with C/2002 S5. Identity with C/2002 S11 is a distinct possibility, although this comet was associated with C/2008 G6 on MPEC 2008-L29.
A sungrazing comet is a comet that passes extremely close to the Sun at perihelion – sometimes within a few thousand kilometres of the Sun's surface. Although small sungrazers can completely evaporate during such a close approach to the Sun, larger sungrazers can survive many perihelion passages.
List of unnumbered Jupiter-Family comets. While Jupiter-family comets are officially defined by (2< T Jupiter <3), they can also be loosely defined by any comet with a period of less than 20 years, a relatively low inclination, and an orbit coinciding loosely with that of Jupiter's.