C / 1948 V1 (eclipse comet)

from Wikipedia, the free encyclopedia
C / 1948 V1 (eclipse comet) [i]
Properties of the orbit ( animation )
Epoch:  October 16, 1948 ( JD 2,432,840.5)
Orbit type long-period
Numerical eccentricity 0.999935
Perihelion 0.135 AU
Aphelion 4167 AE
Major semi-axis 2083 AU
Sidereal period ~ 95,000 a
Inclination of the orbit plane 23.1 °
Perihelion October 27, 1948
Orbital velocity in the perihelion 114.5 km / s
history
Explorer
Date of discovery November 1, 1948
Older name 1948 XI, 1948l
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1948 V1 (eclipse comet ) is a comet that could be seen with the naked eye in 1948 . Some consider it one of the " great comets ".

Discovery and observation

This comet approached from behind the sun when viewed from the earth and could therefore not be seen in the phase of its approach. Already on October 16, 1948, it had passed the sun unobserved from the earth at a distance of less than 1 ° and on October 27 it had passed through the point of its orbit closest to the sun, before being seen a second time on October 31 had passed the sun less than 1 ° away.

On November 1, 1948, a total occurred eclipse that at sunrise in Central Africa began and the darkness path first by the Belgian Congo , Uganda and Kenya went, the further course then only over the Indian Ocean , to the darkness shortly before reaching New Zealand there ended at sunset . During the eclipse of the sun near Nairobi, which lasted a maximum of about 45 seconds, the comet suddenly appeared to the many observers gathered there as a bright object less than 2 ° to the right above the sun with a strongly curved tail of at least 4 ° in length, that towered past the darkened sun to the horizon. Numerous photographs of the event were taken there and also by observers at Mombasa and on board a Royal Air Force aircraft over Kenya. During the subsequent partial eclipse phase, the comet could still be observed for a short time, but was soon lost again when the sky was brightened.

It was not until November 4th that the comet was discovered again by the pilot of a commercial aircraft near Kingston (Jamaica) . In the days that followed, there were still independent discoveries in Australia and South Africa . The brightness of the comet was given by various observers at this time as 1–2 mag with a tail length of 15–20 °. From the middle of the month the brightness of the comet began to decrease and the length of the tail also decreased. At the beginning of December, brightnesses of around 5 mag and tail lengths of 6 ° were described. On December 6th the comet reached its southernmost declination and by December 20th the brightness had dropped below the threshold of visibility with the naked eye.

The comet was still intensely observed telescopically and photographically with further decreasing brightness and the last observation was made on April 3, 1949 at about 17 mag.

It wasn't until about forty years later that a short article appeared in the magazine of an Australian astronomical society in which the writer reports that one afternoon in late October 1948 he was watching the setting sun and discovered a bright comet with a tail near the sun. Since he thought that such a bright object would certainly be known to astronomers, he made no report about it at the time. The exact circumstances of this observation can no longer be inferred, but the report about it appears to be genuine and it probably took place on the evening of October 31st.

The comet reached a maximum brightness of -2 mag.

Orbit

For the comet, a limited precise elliptical orbit could be determined from 147 observation data over a period of 146 days , which is inclined by around 23 ° to the ecliptic . At the point of the orbit closest to the sun ( perihelion ), which the comet traversed on October 27, 1948, it was about 20.3 million km away from the sun, well within the orbit of Mercury . On October 31, it passed Mercury at a distance of about 42.5 million km and on November 7, it passed Venus at about 98.0 million km . On November 24th, the closest approach to earth was reached with about 0.56 AU / 83.1 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 had an eccentricity of around 0.99982 and a semiaxial axis of around 775 AU some time before its passage through the inner solar system in 1948 , so that its orbit period was around 21,500 years. Due to the gravitational pull of the planets, especially due to the relatively close passages of Saturn on June 28, 1947 and Jupiter on October 22, 1948 at a distance of about 5 AU each, the orbital eccentricity was increased to about 0.99993 and the semi-major axis to about 1930 AU so that its orbital period increased to about 85,000 years.

See also

Web links

Individual evidence

  1. ^ John E. Bortle: International Comet Quarterly - The Bright-Comet Chronicles. Retrieved October 3, 2015 .
  2. ↑ NASA Eclipse Web Site - Total Solar Eclipse of 1948 Nov 01. Retrieved October 5, 2015 (English).
  3. ^ Gary W. Kronk : Cometography - A Catalog of Comets. Volume 4: 1933-1959 . Cambridge University Press, Cambridge 2009, ISBN 978-0-521-58507-1 , pp. 311-317.
  4. ^ DAJ Seargent: The Greatest Comets in History: Broom Stars and Celestial Scimitars . Springer, New York 2009, ISBN 978-0-387-09512-7 , p. 237.
  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. ↑ C / 1948 V1 (Finsterniskomet) in the Small-Body Database of the Jet Propulsion Laboratory (English).
  7. ↑ SOLEX 11.0 A. Vitagliano. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
  8. ^ 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 .