C / 1893 U1 (Brooks)

from Wikipedia, the free encyclopedia
C / 1893 U1 (Brooks) [i]
Comet Brooks on October 21, 1893
Comet Brooks on October 21, 1893
Properties of the orbit ( animation )
Period:  September 19, 1893 ( JD 2.412.726.2223)
Orbit type long-period
Numerical eccentricity 0.9965
Perihelion 0.812 AU
Aphelion 462 AU
Major semi-axis 231 AU
Sidereal period ~ 3520 a
Inclination of the orbit plane 129.8 °
Perihelion September 19, 1893
Orbital velocity in the perihelion 46.7 km / s
history
Explorer William R. Brooks
Date of discovery October 17, 1893
Older name 1893 IV, 1893c
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1893 U1 (Brooks) is a comet that could be observed in 1893.

Discovery and observation

William Robert Brooks discovered this comet with a telescope at the Smith's private observatory in Geneva, New York, on the morning of October 17, 1893. He estimated its brightness to be 7 mag and observed a tail 3 ° long. The comet had passed its closest point to the Sun a month earlier, but was moving even closer to Earth at the time of its discovery .

Just one day after its discovery, Edward Barnard was able to determine the exact position of the comet at the Lick Observatory , which initially showed no abnormalities. A day later he took his first photograph. He was then able to determine that the tail of the comet was split into a straight tail almost 4 ° in length and two smaller rays that departed from the head of the comet at an angle. On October 22nd, a deformation of the comet's tail was visually observed for the first time, and a new image “showed the comet's tail like no comet's tail has been seen before. The graceful symmetry was broken, the tail smashed. It was bent, twisted, and deflected, while its greater part was dissolved into knots and nebulous masses, and the whole appearance was like the idea of ​​a torch flickering and blowing irregularly in the wind. "

Barnard was able to continue his photographic documentation of the changes in the comet's tail into November. Meanwhile, the comet moved northwards with decreasing brightness in the sky and could be observed from the northern hemisphere as a circumpolar object throughout the night towards the end of the year . The last observation of the comet was on January 27, 1894.

The comet had an increased brightness on October 31st, which made it visible to the naked eye only on that day . Otherwise, however, it never achieved sufficient brightness to be seen in this way.

Scientific evaluation

Edward Barnard was able to take a total of 17 wide-angle photographs of the comet by November 19. The recordings showed the unusual shape of the tail and its rapid changes. It was also possible to observe individual tail clouds that came off. Together with the observations made the previous year on comet C / 1892 E1 (Swift) , this led to the realization that an interaction takes place between the head of the comet and the changes observed in the tail. The cause of the deformations of the comet's tail could not initially be explained and an unknown slowing medium was suspected in the space between the sun and the planets .

For comet C / 1893 U1, Boris Alexandrowitsch Voronzow-Veljaminow was able to deduce in 1930 that the movement of the tail and its shape can be explained if one assumes that it was continuously emitted in the form of gaseous particles from a solid core with a period of 91 hours rotates around an imaginary axis sun – comet.

The light from the comet was examined spectroscopically by William Wallace Campbell at the Lick Observatory. He could observe the comet-typical emission lines of carbon (C 2 ).

Orbit

For the comet, a limited precise elliptical orbit could be determined from 153 observation data over a period of 82 days , which is inclined by around 130 ° 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 September 19, 1893, it was located at about 121.5 million km from the sun in the area between the orbits of Venus and Earth . On July 14th it had already come close to the earth within 1.15 AU / 172.4 million km and on August 28th it had passed Venus at a distance of 92.1 million km. On September 30, the closest approach to Mars took place at 123.6 million km, and on December 6, the comet once again approached Earth to within 1.31 AU / 195.7 million km.

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 1893 still had an eccentricity of around 0.9956 and a semiaxial axis of around 186 AU, so that its orbit period was around 2530 years. The comet could therefore have appeared in antiquity around the year -630. Due to the gravitational pull of the planets, especially due to the relatively close passages of Jupiter on January 16, 1892 in about 3 ½ AU and on April 15, 1894 in about 3 ¾ AU, its orbital eccentricity was reduced to about 0.9963 and its semi-major axis to enlarged by about 220 AU, so that its orbital period increased to about 3250 years. When it reaches the point of its orbit furthest from the sun ( aphelion ) around the year 3515 , it will be about 65.5 billion km from the sun, almost 438 times as far as the earth and almost 15 times as far as Neptune . The comet's next perihelion passage may occur around the year 5140.

See also

Web links

Individual evidence

  1. ^ EE Barnard: Photographs of Brook's Comet (Oct. 17, 1893). In: Popular Astronomy. Vol. I, No. 4, 1893, pp. 145-147 ( bibcode : 1893PA ...... 1..145B ).
  2. ^ EE Barnard: Photographs of 1893 Brook's Comet. In: Monthly Notices of the Royal Astronomical Society. Vol. LIX, No. 6, 1899, pp. 358-360 ( bibcode : 1899MNRAS..59..358B ).
  3. ↑ GW Kronk: Cometography - A Catalog of Comets, Volume 2. 1800-1899 . Cambridge University Press, Cambridge 2003, ISBN 0-521-58505-8 , pp. 711-714.
  4. ^ A b S. Hughes: Catchers of the Light: The Forgotten Lives of the Men and Women Who First Photographed the Heavens. ArtDeCiel Publishing, 2012, ISBN 978-1-62050-961-6 , p. 668.
  5. ↑ A. Kopff: Comets and Meteors. In: G. Eberhard, A. Kohlschütter, H. Ludendorff (Ed.): Handbook of Astrophysics - Vol. IV The solar system. Springer, Heidelberg 1929, ISBN 978-3-662-38835-8 , p. 459 doi: 10.1007 / 978-3-662-39753-4 .
  6. ↑ RJM Olsen, JM Pasachoff: Fire in the Sky: Comets and Meteors, the Decisive Centuries, in British Art and Science. Cambridge University Press, Cambridge 1998, ISBN 0-521-63060-6 , pp. 256-257.
  7. ^ EE Barnard: On the Anomalous Tails of Comets. In: The Astrophysical Journal. Vol. 22, 1905, pp. 249-255 doi: 10.1086 / 141274 ( bibcode : 1905ApJ .... 22..249B ).
  8. ^ FL Whipple: The Rotation of Comet Nuclei. In: Laurel L. Wilkening, Mildred Shapley Matthews (Ed.): Comets. The University of Arizona Press, 1982, ISBN 0-8165-0769-4 , p. 229.
  9. ^ WW Campbell: Visible Spectrum of Comet c, 1893 (Brooks). In: Publications of the Astronomical Society of the Pacific. Vol. 5, No. 32, 1893, pp. 208-210 doi: 10.1086 / 120678 ( bibcode : 1893PASP .... 5..208C ).
  10. ↑ D. Peyra: . Intorno all'orbita della Cometa 1893 IV In: Astronomical messages. Vol. 137, No. 3281, 1895, pp. 273-290 ( bibcode : 1895AN .... 137..273P ).
  11. ↑ C / 1893 U1 (Brooks) in the Small-Body Database of the Jet Propulsion Laboratory (English).
  12. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .