C / 1976 E1 (Bradfield)
| C / 1976 E1 (Bradfield) [i] | |
|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | parabolic |
| Numerical eccentricity | 1.0 |
| Perihelion | 0.678 AU |
| Inclination of the orbit plane | 147.8 ° |
| Perihelion | February 25, 1976 |
| Orbital velocity in the perihelion | 51.1 km / s |
| history | |
| Explorer | WA Bradfield |
| Date of discovery | March 3, 1976 |
| Older name | 1976 V, 1976d |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 1976 E1 (Bradfield) is a comet which in 1976 could only be observed with optical aids.
Discovery and observation
The comet was on the morning of March 4, 1976 (local time) by William A. Bradfield in Australia with a 150 mm - f / 5.5 - Refractor discovered. It was his sixth comet discovery, just two weeks after his last. During this period he had searched for comets for 9 hours. Bradfield estimated the comet's brightness to be 9 mag.
The comet could also be followed by other observers on the following days, but it did not get any brighter than when it was discovered, as it was already moving away from the sun and earth . The last observation was on March 28, 1976.
Orbit
For the comet, only a relatively imprecise parabolic orbit could be determined from 11 observation data over a period of 22 days by Marsden , which is inclined by around 148 ° 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 traversed on February 25, 1976, it was located 101.5 million km from the sun in the area just inside the orbit of Venus . He had already passed this planet on February 10th at an unusually small distance of only 10.0 million km, and on February 18th he had approached Mercury within 40.8 million km. On March 12th it came close to the earth to about 0.53 AU / 79.0 million km and on April 10th it passed Mars at a distance of 136.5 million km.
Because of the few observations, no precise orbit shape could be calculated for the comet. Nevertheless, an estimate could be made of how the comet's orbit was influenced during its passage through the inner solar system , in particular by passing close to Jupiter on February 12, 1975 in about 3 AU and on March 24, 1977 in only about ⅓ AU. It can therefore be assumed that the semi-major axis of an assumed elliptical orbit has been significantly reduced compared to the original value. The comet could thus return to the inner solar system.
See also
Individual evidence
- ^ Astronomical Society of South Australia: Comets Discovered from South Australia. Accessed December 23, 2015 .
- ^ BG Marsden, DWE Green, E. Roemer: Comets in 1976. In: Quarterly Journal of the Royal Astronomical Society. Vol. 26, 1985, pp. 68-80 ( bibcode : 1985QJRAS..26 ... 68M ).
- ^ 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. 505-506.
- ↑ NASA JPL Small-Body Database Browser: C / 1976 E1 (Bradfield). Accessed December 23, 2015 .
- ↑ 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 ).