C / 1978 T3 (Bradfield)
| C / 1978 T3 (Bradfield) [i] | |
|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | parabolic |
| Numerical eccentricity | 1.0 |
| Perihelion | 0.432 AU |
| Inclination of the orbit plane | 138.3 ° |
| Perihelion | September 29, 1978 |
| Orbital velocity in the perihelion | 64.1 km / s |
| history | |
| Explorer | WA Bradfield |
| Date of discovery | October 10, 1978 |
| Older name | 1978 XVIII, 1978o |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 1978 T3 (Bradfield) is a comet that in 1978 could only be observed with optical aids.
Discovery and observation
On September 15, 1978, the comet had already passed the sun at a distance of just under 1 ½ ° , seen from Earth , without being observed. He was then in 1978 (local time) in the morning of October 11 by William A. Bradfield in Australia with a mm 150 - f / 5.5 - Refractor discovered. It was his eighth comet discovery, just eight months after his last. During this period he had searched for comets for a total of 75 hours. Bradfield estimated the comet's brightness to be 9 mag. The discovery was confirmed by two other observers in Australia the following day.
While the comet was already moving away from the sun, it came even closer to the earth and, for observers, moved up into the southern sky . Its brightness reached 8 mag by the end of October. The last observation was made on November 20, 1978 by Tsutomu Seki in Japan at only 16 mag brightness.
Orbit
For the comet, only relatively imprecise parabolic orbits could be determined from 8 observations over a period of 40 days by Marsden and from 13 observations over a period of 27 days by Nakano , which are inclined by around 138 ° 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 it passed on September 29, 1978, it was located at a distance of about 64.6 million km from the sun in the area of the orbit of Mercury . On August 15, the comet had already come close to Mars up to about 115.0 million km, and on September 22, the closest approach to Mercury was at 32.3 million km. On October 26th it passed Venus in about 39.8 million km and two days later on October 28th it came close to Earth to about 0.40 AU / 60.5 million km.
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 when it passed Jupiter on September 27th at a distance of almost 5 AU. 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 orbit became hyperbolic as a result or whether the comet could return to the inner solar system.
The comet's rapid decrease in brightness towards the end of its observation could indicate that it was dissolving.
See also
Individual evidence
- ^ Astronomical Society of South Australia: Comets Discovered from South Australia. Retrieved January 13, 2016 .
- ^ 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 ).
- ^ Gary W. Kronk , Maik Meyer : Cometography - A Catalog of Comets, Volume 5, 1960-1982. Cambridge University Press, Cambridge 2010, ISBN 978-0-521-87226-3 , pp. 623-624.
- ↑ NASA JPL Small-Body Database Browser: C / 1978 T3 (Bradfield). Retrieved January 13, 2016 .
- ↑ A. Vitagliano: SOLEX 11.0. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
- ^ 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 ).
- ↑ International Comet Quarterly: Split Comets. Retrieved January 13, 2016 .