C / 1970 K1 (White-Ortiz-Bolelli)

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C / 1970 K1 (White-Ortiz-Bolelli) [i]
Properties of the orbit ( animation )
Period:  May 14, 1970 ( JD 2.440.720.9859)
Orbit type parabolic
s. Article text
Numerical eccentricity 1.0
Perihelion 0.0089 AU
Inclination of the orbit plane 139.1 °
Perihelion May 14, 1970
Orbital velocity in the perihelion 447 km / s
history
Explorer Graeme L. White , Emilio Ortiz, Carlos Bolelli, et al. a.
Date of discovery May 18, 1970
Older name 1970 VI, 1970f
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1970 K1 (White-Ortiz-Bolelli) is a comet that in 1970 could only be seen with the naked eye from the southern hemisphere . It belongs to the Kreutz group of sun-grazing comets and is considered by some to be one of the " great comets ".

Discovery and observation

This comet was at noon of May 14, 1970 by the Earth seen in a narrow arch in only 0.36 ° spacing at the sun passed and then moved away quickly to the east of it. Graeme Lindsay White , then still a student, first spotted the comet with binoculars near Shellharbour City ( New South Wales ) at dusk on May 18, 1970 (local time). He estimated its brightness to be 1–2 mag and recognized a tail 1 ° long. A day later he wanted to check his discovery at the observatory in Sydney , but could not see the comet for sure because of the city lights. Another day later he was able to find the comet both with binoculars and with the naked eye, the tail was now 10 ° long.

A few hours after White's report was received by the official agency, another sighting report was received from Madagascar , where Emilio Ortiz, the co-pilot of a Boeing 707 airliner on the flight from St. Denis on Réunion to Antananarivo, hit the comet on the evening of May 21 had also discovered (Ortiz had also been one of the first observers of comet C / 1961 O1 (Wilson-Hubbard) ). Ortiz estimated the brightness to be 0.5–1 mag and the tail length to be 5–8 °. Several astronomers then searched for the comet on May 22, but could not see it. Only two days later there was a belated report of sightings of the comet on the evening of May 21 and 22 by Carlos Bolelli at the Cerro Tololo Inter-American Observatory in Chile . He could observe a brightness of 1 mag and a tail length of 10 °.

Reports were later received of numerous independent discoveries that took place between May 19 and 24 in Australia , South Africa , Chile, Argentina , New Zealand , and Uruguay . In all cases, the comet had only been visible just after sunset at dusk.

The brightness of the comet decreased rapidly to about 5 mag by the end of the month, while the tail initially increased in length, reaching its greatest length of about 15 ° around May 25, and around 5 ° by the end of the month Possessed length. In June the comet could only be observed telescopically and photographically.

The last observations were made on June 7, 1970 at a brightness of about 9 mag in New Zealand and Australia. On July 8th, the comet passed south of the Sun one more time as viewed from Earth, and although attempts to find the comet in the morning sky were unsuccessful until the beginning of October .

The comet reached a maximum brightness of 0.5 mag.

Scientific evaluation

Immediately after the first observation reports, Brian Marsden suspected that the comet could be a member of the Kreutz group's sun streakers . This assumption was confirmed soon after orbital elements of a preliminary parabolic orbit could be determined.

As early as the 19th century, several large comets had appeared, which passed close to the sun like the comet White-Ortiz-Bolelli. 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 , all of which move in very similar orbits, as possible members of the group and even in the 20th century other group members appeared in shape of comets C / 1945 X1 , C / 1963 R1 and C / 1965 S1 .

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 stripes, in particular by Zdenek Sekanina and others.

After Marsden was only able to calculate a relatively imprecise parabolic orbit from six observations of the comet over a period of 14 days (these values ​​are given in the info box) in 1970, Sekanina and Chodas determined improved orbital elements for the comet using modern mathematical methods in a new study in 2002 Methods and taking into account the gravitational influence of all planets and the relativistic effects when the comet flies close to the sun. They calculated a general solution according to which the comet is definitely moving in an elliptical orbit with an orbital period that lies within a range of about 300 to 1130 years. In addition, they calculated an optimized set of orbital elements ("Forced solution") for a forced orbital period of 951 years, which numerically only differs slightly from those of the general solution and can serve as a reference for analyzes of the origin of the comet.

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 White-Ortiz-Bolelli was possibly formed around 1749 during such a decay process.

Orbit

The following information is based on the orbital calculation of Sekanina and Chodas. Then the comet moves in an extremely elongated elliptical orbit, which is inclined by around 139 ° 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 May 14, 1970, it was about 1.33 million km from the sun, just a solar radius above its surface. Already on March 13th he had passed Mars at a distance of about 152.0 million km and on April 30th at a distance of about 72.8 million km from Venus . Almost 2 ½ hours after its perihelion it reached its closest proximity to earth with a distance of 1.00 AU / 149.7 million km. On May 23rd there was a further approach to Venus with a distance of about 63.2 million km and on June 24th to Mars with a distance of about 131.2 million km.

According to recent research, the comet is likely a fragment of an unobserved comet that appeared in the early 12th century. According to the orbital elements determined by Sekanina under the assumption of such an origin ("Forced solution"), its orbit possibly had an eccentricity of about 0.99988 and a semi-major axis of about 90 AU some time before the passage through the inner solar system in 1970 , so that its orbital period was about 860 years. The orbital eccentricity was not significantly changed by the gravitational pull of the planets, but the semi-major axis was enlarged to about 96 AU, so that its orbital period increased to about 935 years. Under these assumptions, the comet's next perihelion passage could possibly take place around the year 2900. 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. ^ John E. Bortle: International Comet Quarterly - The Bright-Comet Chronicles. Retrieved September 25, 2015 .
  2. ^ DAJ Seargent: The Greatest Comets in History: Broom Stars and Celestial Scimitars . Springer, New York 2009, ISBN 978-0-387-09512-7 , p. 207.
  3. ^ BG Marsden: Reports on Progress in Astronomy - Comets in 1970 . In: Quarterly Journal of the Royal Astronomical Society , Vol. 12, 1971, pp. 244-273 ( bibcode : 1971QJRAS..12..244M ).
  4. ^ 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. 269-272.
  5. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy . Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , pp. 271-272.
  6. ↑ BG Marsden: The Sungrazing Comet Group. In: The Astronomical Journal. Vol. 72, No. 9, 1967, pp. 1170-1183 ( bibcode : 1967AJ ..... 72.1170M ).
  7. ^ 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 ).
  8. ^ BG Marsden: IAUC 2261: Comet White-Ortiz-Bolelli (1970f). Retrieved October 16, 2015 .
  9. ↑ NASA JPL Small-Body Database Browser: C / 1970 K1. Retrieved September 29, 2015 .
  10. ↑ Z. Sekanina, PW Chodas: Fragmentation Origin of Major Sungrazing Comets C / 1970 K1, C / 1880 C1, and C / 1843 D1. In: The Astrophysical Journal. Vol. 581, 2002, pp. 1389-1398 doi: 10.1086 / 344261 ( PDF; 146 kB ).
  11. ↑ a b 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 ).
  12. ↑ 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 ).
  13. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .