Comet Pereyra
Encyclopedia
Comet Pereyra was a bright comet
which appeared in 1963. It was a member of the Kreutz Sungrazers
, a group of comets which pass extremely close to the Sun
.
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, at apparent magnitude
2, and had a short tail about one 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
.
, 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 which fragmented several centuries previously.
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 which 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.
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
which appeared in 1963. It was a member of the Kreutz Sungrazers
Kreutz Sungrazers
The Kreutz Sungrazers are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first...
, a group of comets which pass extremely close to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
.
Discovery
The comet was first seen on 14 September 1963, by Z.M. Pereyra of CordobaCórdoba, Argentina
Córdoba is a city located near the geographical center of Argentina, in the foothills of the Sierras Chicas on the Suquía River, about northwest of Buenos Aires. It is the capital of Córdoba Province. Córdoba is the second-largest city in Argentina after the federal capital Buenos Aires, with...
observatory in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
observer George Alcock
George Alcock
George Eric Deacon Alcock was an English astronomer. He was one of the most successful visual discoverers of novae and comets....
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, at apparent magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
2, and had a short tail about one degree
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...
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
Naked eye
The naked eye is a figure of speech referring to human visual perception unaided by a magnifying or light-collecting optical device, such as a telescope or microscope. Vision corrected to normal acuity using corrective lenses is considered "naked"...
visibility it was widely observed throughout the southern hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
.
Orbital studies
As the comet receded from the Sun, orbital studies showed that Pereyra had been a sungrazing cometSungrazing comet
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. While small sungrazers can be completely evaporated during such a close approach to the Sun, larger sungrazers can survive many perihelion passages...
, passing just 60,000 kilometres from the Sun's surface. Further analysis demonstrated that it was a member of the Kreutz Sungrazers
Kreutz Sungrazers
The Kreutz Sungrazers are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first...
, a group of comets all descended from one very large sungrazing comet which fragmented several centuries previously.
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 which includes the Great Comet of 1843
Great Comet of 1843
The Great Comet of 1843 formally designated C/1843 D1 and 1843 I, was a long-period comet which became very bright in March 1843 . It was discovered on February 5, 1843 and rapidly brightened to become a great comet...
and the Great Comet of 1882
Great Comet of 1882
The Great Comet of 1882 formally designated C/1882 R1, 1882 II, and 1882b, was a comet which became very bright in September 1882...
, although the separation of Pereyra from the larger fragment probably occurred one orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
before the two Great Comets separated.