C / 1957 P1 (Mrkos)

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C / 1957 P1 (Mrkos) [i]
Mrkos 1957A.jpg
Properties of the orbit ( animation )
Period:  July 21, 1957 ( JD 2,436,040.5)
Orbit type long-period
Numerical eccentricity 0.99937
Perihelion 0.355 AU
Aphelion 1118 AU
Major semi-axis 559 AU
Sidereal period ~ 13,000 a
Inclination of the orbit plane 93.9 °
Perihelion August 1, 1957
Orbital velocity in the perihelion 70.7 km / s
history
Explorer Antonin Mrkos
Date of discovery 2nd August 1957
Older name 1957 V, 1957d
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1957 P1 (Mrkos) is a comet that could be seen with the naked eye in 1957 . Some consider it one of the " great comets ".

Discovery and observation

Antonín Mrkos , an experienced asteroid and comet discoverer, found this comet with the naked eye in the early morning of August 2, 1957 from Lomnický štít in Slovakia . He estimated the brightness to be 3 mag and observed a tail 1 ° long. The discovery was confirmed by an observer in Denmark on the evening of the same day . Additional reports of independent discoveries were received after the discovery was officially announced. The first observation of the comet then took place on the evening of July 29th by S. Kuragano in Yokohama . His report was only forwarded after 2 weeks. On July 31, the comet was also seen by the pilot of an airliner over Colorado . His report also arrived at the official site with a delay of almost a week. In the days that followed, there were still numerous discoveries in England , the United States and Canada .

The comet had approached from the direction of the sun unnoticed by observers on earth and was only discovered when it had moved sufficiently far away from the sun in perspective. As a result, at this point in time it had an unusually high brightness and a well-developed tail for a newly discovered comet.

On August 8, the comet reached its greatest northern declination and its brightness had increased to 1–2 mag. At the time of its discovery, an object in the morning sky , from now on it could be observed in the evening sky , but when it was dark enough, it was always close to the horizon. The comet was described on August 11th with a very bright orange-yellow core and a 4 ° long tail. The tail showed an extraordinarily complex and dynamic structure with several straight rays and a broad curved portion. The linear ion tail showed a turbulent movement, which changed its appearance from hour to hour, while the shorter curved dust tail (eg. As in the comets only rarely before / 1743 X1 C ) observed phenomenon of parallel strips ( striae ) showed. From the middle of the month, the brightness and tail length only decreased slowly. At the end of August the brightness was around 3–4 mag and the tail length was 2 °.

From around the middle of September the comet could no longer be seen with the naked eye, but it was initially observed telescopically and photographically until the beginning of October. On December 1st, the comet passed the sun at a distance of about 3.5 ° from Earth. From the end of January 1958, photographic images of the comet could again be obtained. The last observation was made on July 9, 1958 by Elizabeth Roemer in Flagstaff .

The comet reached a maximum brightness of 1 mag.

Scientific evaluation

In the first half of August 1957, several spectrographic observations of the comet took place at the Palomar Observatory and the Observatoire de Haute-Provence . For the first time, high-resolution spectra were recorded from a comet. The spectrograms showed comet-typical emission lines , u. a. of NH 2 , C 2 and CN, but also the "forbidden" lines of neutral oxygen , as well as strongly pronounced sodium D-lines , which was the cause of the yellow coloration of the comet's head.

The light of the comet was also examined with regard to its polarization , both for the total light and only for certain wavelength ranges, as well as with regard to its color.

Orbit

Zdenek Sekanina was able to determine an elliptical orbit for the comet from 108 observation data over a period of 338 days , which is inclined by around 94 ° to the ecliptic . The comet's orbit is thus almost perpendicular to the planets' orbital plane. At the point of the orbit closest to the sun ( perihelion ), which the comet passed on August 1, 1957, it was located at a distance of 53.1 million km from the sun in the area of ​​the orbit of Mercury . On August 13th it reached the closest approach to Earth with about 1.06 AU / 159.3 million km , while on August 17th it reached Mercury at a distance of about 88.6 million km and on September 2nd approximately 81.3 million km distance passed Venus .

The comet moves in an extremely elongated elliptical orbit around the sun. According to the orbital elements , which are afflicted with a certain uncertainty, its orbit before its passage through the inner solar system in 1957 still had an eccentricity of about 0.9993 and a semi-major axis of about 500 AU, so that its orbit period was about 11,200 years. Due to the gravitational pull of the planets, especially due to two relatively close passages of Jupiter on June 13, 1957 in about 5 AU and on December 2, 1958 in just under 3 AU, and on Saturn on January 17, 1959 in about 5 AU, the orbital eccentricity was reduced to about 0.9989 and the semi-major axis to about 325 AU, so that its orbit period was shortened to about 5845 years. When it reaches the point of its orbit furthest from the sun ( aphelion ) around the year 4880 , it will be about 97 billion km from the sun, almost 650 times as far as the earth and almost 22 times as far as Neptune . Its orbital speed in aphelion is only about 0.04 km / s. The comet's next perihelion passage may occur around the year 7800.

See also

Web links

Individual evidence

  1. ^ John E. Bortle: International Comet Quarterly - The Bright-Comet Chronicles. Retrieved September 25, 2015 .
  2. ^ MJ 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 .
  3. ↑ Ch. Bertaud: Les comètes brillantes apparues depuis 1956. In: L'Astronomie. Vol. 89, 1975, pp. 75-83, bibcode : 1975LAstr..89 ... 75B .
  4. ^ Gary W. Kronk : Cometography - A Catalog of Comets. Volume 4: 1933-1959 . Cambridge University Press, Cambridge 2009, ISBN 978-0-521-58507-1 , pp. 536-541.
  5. ^ P. Moore, R. Rees: Patrick Moore's Data Book of Astronomy . Cambridge University Press, Cambridge 2011, ISBN 978-0-521-89935-2 , p. 271.
  6. ↑ JL Greenstein: High-Resolution Spectra of Comet Mrkos (1957d). In: Astrophysical Journal. Vol. 128, 1958, p. 106, doi: 10.1086 / 146521 , bibcode : 1958ApJ ... 128..106G .
  7. ^ Nguyen-Huu-Doan: Le specter de la Comète 1957 d. In: Journal des Observateurs. Vol. 43, 1960, pp. 61-68, bibcode : 1960JO ..... 43 ... 61N .
  8. ^ P. Swings: Cometary Spectra. In: Quarterly Journal of the Royal Astronomical Society. Vol. 6, 1965, pp. 28-69, bibcode : 1965QJRAS ... 6 ... 28S .
  9. ↑ JL Greenstein, C. Arpigny: The Visual Region of the Spectrum of Comet Mrkos (1957d) at high resolution. In: Astrophysical Journal. Vol. 135, 1962, pp. 892-905, doi: 10.1086 / 147333 , bibcode : 1962ApJ ... 135..892G .
  10. ↑ MK Vainu Bappu, SD Sindvhal: Polarization Measures of Comet Arend-Roland (1956h) and Comet Mrkos (1957d). In: Monthly Notices of the Royal Astronomical Society. Vol. 120, 1960, pp. 152-162, bibcode : 1960MNRAS.120..152V .
  11. ↑ NASA JPL Small-Body Database Browser: C / 1957 P1. Retrieved September 28, 2015 .
  12. ^ BG 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 .
  13. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .