C / 1979 M1 (Bradfield)
| C / 1979 M1 (Bradfield) [i] | |
|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type |
hyperbolic (see article text) |
| Numerical eccentricity | 1.000059 |
| Perihelion | 0.413 AU |
| Inclination of the orbit plane | 136.2 ° |
| Perihelion | July 23, 1979 |
| Orbital velocity in the perihelion | 65.5 km / s |
| history | |
| Explorer | WA Bradfield |
| Date of discovery | June 24, 1979 |
| Older name | 1979 VII, 1979c |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 1979 M1 (Bradfield) is a comet that in 1979 could only be observed with optical aids.
Discovery and observation
The comet was on the evening of June 24, 1979 (local time) by William A. Bradfield in Australia with a 150 mm - f / 5.5 - Refractor discovered. It was his ninth comet discovery, just eight months after his last. During this period he had searched for comets for a total of 98 hours. Bradfield estimated the comet's brightness to be 10 mag.
The comet was initially only tracked from the southern hemisphere until July , after which it was initially no longer observable because of its proximity to the sun . After its closest approach to the sun, the comet moved rapidly north and east to observers on Earth and was then also visible from the northern hemisphere . When it was found again at the beginning of August, however, it was hardly brighter than a month earlier, with brightnesses of up to 8.6 mag. At the beginning of September there was a rapid decrease in brightness and in mid-September, when it came closest to earth, its brightness had already fallen to below 12 mag. The last observation was on September 24, 1979 when only 19 mag was left.
Orbit
For the comet, only a relatively imprecise hyperbolic orbit could be determined from 18 observation data over a period of 91 days by Marsden , which is inclined by around 136 ° to the ecliptic . It 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 July 23, 1979, it was located at a distance of 61.8 million km from the sun in the area of the orbit of Mercury . Just two days later, on July 25th, it passed about 68.6 million km past Venus and on September 15, it came close to Earth to about 0.43 AU / 64.5 million km.
One study showed that the comet's orbit was hyperbolic for only a short period of time. Long before it approached the inner solar system in 1979, the comet was still moving on an extremely elongated elliptical orbit with an orbital eccentricity very close to (but less than) 1 and a semi-major axis of about 30,000 AU. It thus had an orbital period in the order of magnitude of 5 million years. It may have been a “dynamic new” comet from the Oort cloud, or had only come close to the sun a few times before. Due to the gravitational pull of the planets, especially when Jupiter passed on July 12, 1979 at a distance of about 5 AU, the orbital eccentricity was reduced to about 0.99995 and the semi-major axis to about 7900 AU, so that its orbital period is now about 700,000 years lies.
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 14, 2016 .
- ^ BG Marsden: Comets in 1979 . In: Quarterly Journal of the Royal Astronomical Society , Vol. 26, 1985, pp. 106-114 ( bibcode : 1985QJRAS..26..106M ).
- ↑ NASA JPL Small-Body Database Browser: C / 1979 M1 (Bradfield). Retrieved January 14, 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 .