C / 1963 R1 (Pereyra)

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C / 1963 R1 (Pereyra) [i]
Properties of the orbit ( animation )
Epoch:  September 8, 1963 ( JD 2,438,280.5)
Orbit type long-period
Numerical eccentricity 0.999946
Perihelion 0.0051 AU
Aphelion 187.6 AU
Major semi-axis 93.8 AU
Sidereal period 903 a
Inclination of the orbit plane 144.6 °
Perihelion 23rd August 1963
Orbital velocity in the perihelion 592 km / s
history
Explorer Zenon M. Pereyra
Date of discovery September 14, 1963
Older name 1963 V, 1963e
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1963 R1 (Pereyra) is a comet that could be seen with the naked eye in 1963 . He belongs to the Kreutz group of sun-grazing comets.

Discovery and observation

On August 23, 1963, the comet was still unobserved from about 22:20 UT for about 45 minutes from the Earth seen from in front of the sun passed. The comet was only discovered on the morning of September 14th by Zenón M. Pereyra at the observatory in Córdoba (Argentina) . He observed a brightness of 2 mag and a tail longer than 1 ° . The comet was photographed there for the first time the following day .

On September 16, the comet by an observer in was California with a pair of binoculars in the bright dawn seen. The brightness was estimated to be 6 mag and the tail length to be over 10 °. The tail is said to have had “a ghostly appearance” in binoculars and looked “like a weak searchlight”. There were other independent discoveries on September 17th, including a. by John Caister Bennett in South Africa .

In the further course of September the brightness of the comet decreased further to about 8 mag, while the length of the tail decreased to about 1 °. In the months that followed, the comet quickly faded, with Elizabeth Roemer's last observation in Flagstaff on December 18.

The comet reached a maximum brightness of 2 mag.

Scientific evaluation

The first useful orbital elements for the comet in the form of parabolic orbits were calculated by Michael Philip Candy and Leland E. Cunningham in October 1963. Cunningham was the first to recognize the orbit's similarity to that of other sun-grazing comets. In the following years, especially by Zdenek Sekanina and Brian Marsden, elliptical orbits were calculated for the comet. Marsden, Sekanina, and Everhart also determined original and future orbits.

As early as the 19th century , several large comets had appeared, which passed close to the sun like the comet Pereyra. From 1888 to 1901, the sun streakers were examined very intensively by Heinrich Kreutz , who suspected that all members of the comet group that was later named after him descended from an original body that broke when it passed in the sun. He identified the comets C / 1843 D1 , C / 1880 C1 , C / 1882 R1 and C / 1887 B1 , which all move in very similar orbits, as possible members of the group and also appeared in the 20th century in addition to the comet Pereyra further group members in the form of comets C / 1945 X1 , C / 1965 S1 and C / 1970 K1 .

Marsden had already investigated the orbits of the previously known comets of the Kreutz group in 1967 and showed that their members can be divided into two subgroups. He was able to deduce as well as proven that the comets of the Kreutz group must have been fragments of a common comet of origin, which had probably passed the sun in the first half of the 12th century . Whether this was the well-known comet X / 1106 C1 could not be proven at first. As a result, there were many attempts to theoretically capture the possible processes of decay and the resulting trajectories of the sun streaks, in particular by Sekanina and others.

In further very extensive investigations, Sekanina and Chodas developed new theories about the origin and development of the Kreutz comet group, which currently reflect the current state of knowledge. According to the model of the two super fragments, it can be assumed that all the sun streakers of the Kreutz group descend from a very large predecessor comet with a diameter of almost 100 km, which may have been in the late 4th century or early 5th century a few decades before it passed the sun has broken in two roughly equal parts. The two super fragments made one more orbit around the sun and super fragment I reappeared in 1106 as the famous sun streaker X / 1106 C1. Superfragment II appeared only a few years earlier or later, but apparently escaped observation due to unfavorable viewing conditions as there are no reports about it. Both super fragments broke into further fragments again shortly after their extremely close passage to the sun, internally damaged by the enormous tidal forces ( cascading fragmentation ): Superfragment II disintegrated into five further parts, the two largest of which reappeared later as comet C / 1882 R1 and C / 1965 S1, while the other three parts disintegrated into further fragments at different times. The comet Pereyra was possibly formed around 1847 during such a decay process.

Orbit

For the comet, Marsden was able to determine orbit elements from 33 observation data over a period of 94 days, taking into account the orbital disturbances caused by all planets , which are also given in the info box. Then the comet moves in an extremely elongated elliptical orbit, which is inclined by around 145 ° to the ecliptic . The comet thus runs in the opposite direction (retrograde) like the planets through its orbit. At the point of the orbit closest to the sun ( perihelion ), which the comet traversed on August 23, 1963, it was located at a distance of about 758,000 km from the sun, only 1/10 of the solar radius above its surface. On August 6th it had already passed Venus in about 83.8 million km and 1 ½ hours before its perihelion it had reached its closest proximity to the earth at 1.00 AU / 150.1 million km. On August 29, there was another approach to Venus up to a distance of about 84.5 million km.

According to recent research, the comet is likely a fragment of an unobserved comet that appeared in the early 12th century. Under this boundary condition, Sekanina determined on a theoretical basis orbital elements (“Computed Elements”) that differ only minimally from the orbital elements that Marsden had determined on the basis of observations of the comet. According to this, some time before its passage through the inner solar system in 1963 , its orbit still had an eccentricity of about 0.99993 and a semi-major axis of about 90 AU, so that its orbital period was about 856 years. Due to the gravitational pull of the planets, especially by passing Uranus on May 27, 1957 at a distance of about 14 AU and at Jupiter on August 17, 1963 at about 5 AU, the orbital eccentricity was reduced to about 0.99991 and the semi-major axis to about 82 .5 AU reduced so that its orbital period was shortened to about 750 years. If the comet continues to exist unchanged, it will reach the point furthest from the sun ( aphelion ) of its orbit around the year 2336 , it will then be about 24.7 billion km from the sun, 171 times as far as the earth and almost 6- times as far as Neptune . The comet's next perihelion passage would then possibly take place around the year 2713. Based on the prehistory, however, it can be assumed that another spontaneous decay process can take place for the comet at any time.

See also

Web links

Individual evidence

  1. ^ GW Kronk, M. Meyer: Cometography - A Catalog of Comets. Volume 5: 1960-1982 . Cambridge University Press, Cambridge 2010, ISBN 978-0-521-87226-3 , pp. 99-104.
  2. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy . Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , p. 272.
  3. ↑ a b B. G. Marsden, Z. Sekanina, E. Everhart: New Osculating Orbits for 110 Comets and Analysis of Original Orbits for 200 Comets. In: The Astronomical Journal. Vol. 83, No. 1, 1978, pp. 64-71 doi: 10.1086 / 112177 ( bibcode : 1978AJ ..... 83 ... 64M ).
  4. ↑ BG Marsden: The Sungrazing Comet Group. In: The Astronomical Journal. Vol. 72, No. 9, 1967, pp. 1170-1183 ( bibcode : 1967AJ ..... 72.1170M ).
  5. ^ Z. Sekanina: Problems of origin and evolution of the Kreutz family of Sun-grazing comets. In: Acta Universitatis Carolinae. Mathematica et Physica. Vol. 8, No. 2, 1967, pp. 33-84 ( PDF; 4.73 MB ).
  6. ↑ a b c Z. Sekanina, PW Chodas: Fragmentation Hierarchy of Bright Sungrazing Comets and the Birth and Orbital Evolution of the Kreutz System. I. Two-Superfragment Model. In: The Astrophysical Journal. Vol. 607, 2004, pp. 620-639 doi: 10.1086 / 383466 ( PDF; 331 kB ).
  7. ↑ a b Z. Sekanina, PW Chodas: Fragmentation Hierarchy of Bright Sungrazing Comets and the Birth and Orbital Evolution of the Kreutz System. II. The Case for Cascading Fragmentation. In: The Astrophysical Journal. Vol. 663, 2007, pp. 657-676 doi: 10.1086 / 517490 ( PDF; 551 kB ).
  8. ↑ NASA JPL Small-Body Database Browser: C / 1963 R1. Retrieved October 21, 2015 .
  9. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .