C / 1978 C1 (Bradfield)

from Wikipedia, the free encyclopedia
C / 1978 C1 (Bradfield) [i]
Properties of the orbit ( animation )
Period:  March 17, 1978 ( JD 2,443,585.1906)
Orbit type parabolic
Numerical eccentricity 1.0
Perihelion 0.437 AU
Inclination of the orbit plane 51.1 °
Perihelion March 17, 1978
Orbital velocity in the perihelion 63.7 km / s
history
Explorer WA Bradfield
Date of discovery 4th February 1978
Older name 1978 VII, 1978c
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles .

C / 1978 C1 (Bradfield) is a comet that could be seen in 1978.

Discovery and observation

The comet was in 1978 (local time) on the morning of February 5 out of William A. Bradfield in Australia with a mm 150 - f / 5.5 - Refractor discovered. It was his seventh comet discovery, almost two years after his last. During this period he searched for comets for a total of 360 hours. Bradfield estimated the comet's brightness to be 8 mag. The comet was later identified on a photograph taken on January 24th.

During February the comet could only be observed from the southern hemisphere , during which its brightness increased to about 6 mag. It was only possible to observe it from the northern hemisphere at the beginning of March and in this month reached brightnesses of up to 5 mag and a tail length of just under 1 ° . The last observation was made on March 29, 1978, after which the comet could not be observed because of its proximity to the sun . In September and October there were several attempts to find the comet photographically, but they were unsuccessful.

Scientific evaluation

The light from the comet's head was examined spectroscopically on March 5th and 6th at the Uttar Pradesh State Observatory , the emission lines of C 2 and Na were detected.

On March 15th, strong emission lines of C 2 , NH 2 and H 2 O + were detected at the Lick Observatory , while those of Na and O were difficult to observe due to the low height of the comet above the horizon.

A radio telescopic search for emissions of gas molecules, which could already be detected at comet C / 1973 E1 (Kohoutek) , remained without result, a relatively low gas production of comet Bradfield was derived from it. A search for emissions of OH also only resulted in a very weak signal.

Orbit

For the comet, only a relatively imprecise parabolic orbit could be determined from 72 observation data over a period of 34 days by both Marsden and Nakano , which is inclined by around 51 ° to the ecliptic . At the point of the orbit closest to the sun ( perihelion ), which the comet passed on March 17, 1978, it was located 65.3 million km from the sun in the area of ​​the orbit of Mercury . On March 4th it had already come close to the earth to within 1.16  AU / 173.7 million km. On April 13, the comet passed Venus some 82.8 million km away .

Due to the few observations, no closed orbit could be calculated for the comet. Nevertheless, it was possible to estimate how the comet's orbit was influenced during its passage through the inner solar system , in particular by passing close to Jupiter on January 19, 1978 in about 5 ¾ AU and on October 27, 1978 in only about 2 ¾ AU Distance. It can therefore be assumed that the eccentricity of the path has tended to be increased even further. Due to the uncertain initial data, however, no definitive statement can be made as to whether the shape of the orbit is now hyperbolic or whether the comet could return to the inner solar system.

See also

Web links

Individual evidence

  1. ^ Astronomical Society of South Australia: Comets Discovered from South Australia. Retrieved January 12, 2016 .
  2. ^ A b B. G. Marsden, DWE Green: Comets in 1978. In: Quarterly Journal of the Royal Astronomical Society. Vol. 26, 1985, pp. 92-105 ( bibcode : 1985QJRAS..26 ... 92M ).
  3. ^ 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. 592-594.
  4. ^ US Chaubey: Emissions from the Head of Comet Bradfield (1978c). In: Astrophysics and Space Science. Vol. 64, 1979, pp. 53-56 doi: 10.1007 / BF00640032 ( bibcode : 1979Ap & SS..64 ... 53C ).
  5. ^ BG Marsden: IAUC 3199: 1978a; 1978c. Retrieved January 12, 2016 .
  6. ↑ FP Schloerb, WM Irvine, SE Robinson: A search for millimeter-wave emission from HCN, CO, and CH 3 CN in Comet Bradfield (1978c). In: Icarus. Vol. 38, 1979, pp. 392-397 doi: 10.1016 / 0019-1035 (79) 90194-5 .
  7. ↑ D. Despois, E. Gérard, J. Crovisier, I. Kazès: The OH Radical in Comets: Observation and Analysis of the Hyperfine Microwave Transitions at 1667 MHz and 1665 MHz. In: Astronomy and Astrophysics. Vol. 99, no. 2, 1981, pp. 320-340 ( bibcode : 1981A & A .... 99..320D ).
  8. ^ BG Marsden: IAUC 3233: 1977o; 1978c; 4U 1626-67. Retrieved January 12, 2016 .
  9. ↑ NASA JPL Small-Body Database Browser: C / 1978 C1 (Bradfield). Retrieved January 12, 2016 .
  10. ↑ A. Vitagliano: SOLEX 11.0. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
  11. ^ E. Everhart, BG Marsden: New original and future cometary orbits. In: The Astronomical Journal. Vol. 88, 1983, pp. 135-137 doi: 10.1086 / 113298 ( bibcode : 1983AJ ..... 88..135E ).