C / 1956 R1 (Arend-Roland)

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C / 1956 R1 (Arend-Roland) [i]
Comet Arend-Roland 1957.jpg
Properties of the orbit ( animation )
Epoch:  July 9, 1957 ( JD 2,436,028.5)
Orbit type hyperbolic
Numerical eccentricity 1,00025
Perihelion 0.316 AU
Inclination of the orbit plane 119.9 °
Perihelion April 8, 1957
Orbital velocity in the perihelion 74.9 km / s
history
Explorer Sylvain Arend , Georges Roland
Date of discovery November 8, 1956
Older name 1957 III, 1956h
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1956 R1 (Arend-Roland) was a comet that could be seen with the naked eye in 1957 . Due to its extraordinary brightness, it is counted among the " Great Comets ".

Discovery and observation

Sylvain Arend and Georges Roland from the Royal Observatory in Uccle discovered this comet on November 8, 1956, on two 50-minute recordings made by a 40 cm astrograph . They estimated the brightness to be 10 mag. It was not until November 20 that the discovery was confirmed by a control photograph. Shortly afterwards, Sigeru Kaho from the Tokyo Astronomical Observatory found an image of the comet on a photo plate that he had already exposed on November 7th.

Since the earth moved further away from the comet on its orbit, its brightness did not increase significantly until the end of the year and until mid-February 1957. By the end of February the brightness had reached about 7.5 mag. On March 20, the comet flew past the Sun at a distance of 14 ° from Earth and reached its southernmost declination on April 1, which means that it was only observable from the southern hemisphere for a while . A little later it was moving rapidly northwards and towards its closest approach to Earth.

On April 6th the brightness had reached 3 to 4 mag and a tail 3 to 5 degrees long had formed. On April 10th the comet was also seen with the naked eye, on April 13th it reached 1 mag brightness and on April 16th it passed the sun one more time, this time at a distance of 5 °. A little later he was observed again by several observatories in the northern hemisphere . The brightness slowly decreased again as the comet moved away from the sun and from April 20th also from the earth, but the tail length of the comet continued to take on larger values, which reached 30 ° in the second half of April. Most interesting, however, was the appearance of a tail pointing towards the sun. This counter-tail of "spear-like" shape reached lengths of 10 to 15 °.

In the last days of April the comet's brightness had dropped to around 3 to 4 mag. The tail was still about 17 ° long and the opposite tail almost disappeared. In mid-May the brightness had dropped to 5 to 6 mag and the tail was only 1 to 2 ° long. The comet could be followed telescopically until the following year. On February 15, 1958, it passed the Polarstern at a distance of only 0.1 ° . The last observation was made with a 102 cm reflector on April 11 at a brightness of about 21 mag.

The comet reached a brightness of 1 mag.

Scientific evaluation

Due to the early discovery and since the first orbit calculations showed good observation conditions from the spring of 1957, the comet already received a lot of attention from the public and astronomers in advance. This comet was probably also the first to be observed from Antarctica , as several expeditions were there on the occasion of the International Geophysical Year .

In Belgium at Easter 1957, H. de Thier used a Fairchild C-119 of the Air Force to observe the comet. Only above 3000 m could the cloud cover break through and the comet could be observed. On the same evening a second 90-minute flight was undertaken, in which, in addition to the Belgian King Baudouin , the co-discoverer Georges Roland also took part.

Numerous spectrograms could be obtained from the comet . They showed "an extreme variability of the spectrum and an abnormally elevated and variable intensity of double sodium - line ". From the strength of the continuum scattered by the tail, an average size of the dust particles of 0.5 to 4 µm and a mass of the visible tail of the order of 10 11  kg could be estimated. Investigations into the polarization and radio emissions of the comet were also undertaken.

Orbit

In 2014, a very precise hyperbolic orbit could be determined for the comet from around 56 observation data over a period of 15 months , which is inclined by around 120 ° 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 passed on April 8th, it was located at a distance of 47.3 million  km from the sun in the area within the orbit of Mercury . On January 3rd he had already passed Mars at a distance of 117.0 million km and on March 22nd, Venus at a distance of 69.2 million km. On April 20, it reached the  closest approach to earth with 0.57  AU = 85.1 million km . Two days later it passed Mercury at a distance of 37.8 million km .

The comet moves on a hyperbolic, i.e. H. a non-closed orbit through the solar system . In an investigation, Zdenek Sekanina came to the conclusion that it was probably a “dynamic new” comet from the Oort cloud . Before it approached the sun, the eccentricity of its orbit was already around 1.00004. Due to the attraction of the planets, the hyperbolic shape of its orbit was reinforced, so that the eccentricity after leaving the inner solar system is around 1,00021. The comet will therefore not return to the inner solar system.

Reception in the media

The comet has been reported in many newspapers and magazines around the world. The German weekly newspaper “Die Zeit” published a detailed article on April 4, 1957 about the comet Arend-Roland and about the state of comet research in general. TV programs such as the BBC's new series “ The Sky at Night ” also made a big contribution to the comet's popularity.

Max Frisch revised the original version of his novel Homo faber before publication in 1957 to include the appearance of the comet in the plot.

On May 28, 1966, a special stamp for 6  francs was issued in Belgium for the 10th anniversary of the comet's discovery.

See also

Web links

Individual evidence

  1. ^ A b Georges Roland: Les cinq comètes «belges». In: Ciel et Terre. Vol. 101, 1968, pp. 123-128 ( bibcode : 1985C & T ... 101..123R ).
  2. ^ A b Gary W. Kronk : Cometography - A Catalog of Comets. Volume 4: 1933-1959. Cambridge University Press, Cambridge 2009, ISBN 978-0-521-58507-1 , pp. 508-521.
  3. ↑ Michael J. Hendrie: The two bright comets of 1957. In: Journal of the British Astronomical Association. Vol. 106, No. 6, 1996, pp. 315-330 ( bibcode : 1996JBAA..106..315H ).
  4. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy. Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , p. 271.
  5. ^ MK Vainu Bappu, SD Sinvhal: Polarization Measures of Comet Arend-Roland (1956h) and Comet Mrkos (1957d). In: Monthly Notices of the Royal Astronomical Society. Vol. 120, no. 2, 1960, pp. 152-162 doi: 10.1093 / mnras / 120.2.152 .
  6. ↑ R. Coutrez, J. Hunaerts, A. Koeckelenbergh: Radio Emission from Comet 1956 h on 600 MC. In: Proceedings of the IRE. Vol. 46, no. 1, 1958, pp. 274-279 doi: 10.1109 / JRPROC.1958.286787 .
  7. ↑ C / 1956 R1 (Arend-Roland) in the Small-Body Database of the Jet Propulsion Laboratory (English).
  8. ^ Zdenek Sekanina: A Dynamic Investigation of Comet Arend-Roland 1957 III. In: Bulletin of the Astronomical Institute of Czechoslovakia. Vol. 19, No. 6, 1968, pp. 343-350 ( bibcode : 1968BAICz..19..343S ).
  9. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
  10. ↑ Leo Nitschmann: "Arend Roland" is approaching. In: The time . April 4, 1957, accessed October 13, 2014 .
  11. ^ Colnect. Retrieved October 16, 2014 .