| Comet Pereyra | |
| Discoverer: | Zenon M. Pereyra |
| Discovery Date: | 14 September 1963 |
| Designations: | C/1963 R1, 1963 V, 1963e |
| Orbit Ref: | [1] |
| Epoch: | 1963-Oct-25.0 |
| Observation Arc: | 86 days |
| Obs: | 12 |
| Aphelion: | 182 AU |
| Perihelion: | 0.005 AU |
| Semimajor: | 91 AU |
| Eccentricity: | 0.999945 |
| Period: | 875 years (1800) 870 years (1963) 765 years (2200)[2] |
| Inclination: | 144.60° |
| Asc Node: | 8.05° |
| Arg Peri: | 86.23° |
| Earth Moid: | 0.56 AU |
| M2: | 14.3 |
| Last P: | 23 August 1963 |
Comet Pereyra (formal designations: C/1963 R1, 1963 V, and 1963e) was a bright comet that appeared in 1963. It was a member of the Kreutz Sungrazers, a group of comets that pass extremely close to the Sun.
The comet was first seen on 14 September 1963 by Z.M. Pereyra of the Cordoba Observatory in Argentina. British observer George Alcock later reported that he had observed a thin pencil-like beam of light low in the sky on 12 September, which may have been the comet's tail.
It was bright, with an apparent magnitude of 2, and had a short tail about 1 degree long. Over the next few days, the comet faded rapidly, having evidently already passed perihelion, although its tail grew to about 10° in length by late September. During its short period of naked eye visibility, it was widely observed throughout the southern hemisphere.
As the comet receded from the Sun, orbital studies showed that Pereyra had been a sungrazing comet, passing just 60,000 kilometres from the Sun's surface. Further analysis demonstrated that it was a member of the Kreutz Sungrazers, a group of comets all descended from one very large sungrazing comet that fragmented several centuries ago.
The Kreutz Sungrazers consist of two major subgroups, which are descended from further breakups of two different fragments of the original comet. Studies have shown that Pereyra is a member of the subgroup that includes the Great Comet of 1843 and the Great Comet of 1882, although the separation of Pereyra from the larger fragment probably occurred one orbit before the two Great Comets separated.