C / 1930 L1 (Forbes)
| C / 1930 L1 (Forbes) [i] | |
|---|---|
| Properties of the orbit ( animation ) | |
| Orbit type | parabolic |
| Numerical eccentricity | 1.0 |
| Perihelion | 1.15 AU |
| Inclination of the orbit plane | 97.1 ° |
| Perihelion | May 10, 1930 |
| Orbital velocity in the perihelion | 39.2 km / s |
| history | |
| Explorer | AFI Forbes |
| Date of discovery | May 31, 1930 |
| Older name | 1930 v, 1930e |
| Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . Please also note the note on comet articles . | |
C / 1930 L1 (Forbes) is a comet that was observed in 1930.
Discovery and observation
The comet was on the morning of May 31 1930 by Alexander Forbes from his private observatory in Cape Town in South Africa with an 8-inch - Reflector discovered. It was his third comet discovery. He immediately informed the Union Observatory in Johannesburg , where an exact position could be determined just two days later. The comet had a magnitude of 9 mag at that time .
The comet was initially only visible from the southern hemisphere . It had already passed its closest point to the sun three weeks before its discovery, but was getting closer to the earth , so that it remained clearly visible until the end of June. From the beginning to the middle of June the comet was regularly observed by the Johannesburg observatory, then it became visible to observers in the northern hemisphere and in the last week of June it was also followed from the Athens National Observatory .
From June 21 to July 17, the comet was then observed at the Yerkes Observatory . The brightness of the comet was at the beginning of the observations at 11 mag, but it continued to decrease and at the end only reached 15 mag. A short, broad tail could be seen in the last week of June . The last position of the comet was determined on July 21, 1930.
Orbit
For the comet, only a parabolic orbit with limited accuracy could be determined from 54 observation data over a period of 49 days , which is inclined by around 97 ° to the ecliptic . Its orbit is thus almost perpendicular to the orbits of the planets . At the point of the orbit closest to the sun ( perihelion ), which the comet last traversed on May 10, 1930, it was located at a distance of 172.5 million km from the sun in the area slightly outside the orbit of the earth . On June 21, it came close to Earth to within 0.37 AU / 54.8 million km.
Due to the gravitational pull of the planets, in particular due to the close passage of Jupiter on August 23, 1929 at a distance of about 3 ⅓ AU, the eccentricity of the comet's orbit was slightly reduced by about 0.00028 relative to its value before it approached the inner solar system . Due to the uncertain initial data, however, no definitive statement can be made as to whether the orbit became elliptical or whether and when the comet could return to the inner solar system.
See also
Individual evidence
- ^ TP Cooper: A history of comet discovery from South Africa. In: Monthly Notes of the Astronomical Society of Southern Africa. Vol. 62, 2003, pp. 170-179. ( bibcode : 2003MNSSA..62..170C )
- ↑ Photographic Observations of Comet 1930 e (Forbes). In: Circular of the Union Observatory Johannesburg. Vol 84, 1930, p. 172 ( bibcode : 1931CiUO ... 84..172. )
- ↑ S. Plakidis: Observations of Comet Forbes (1930E). In: Monthly Notices of the Royal Astronomical Society. Vol. 91, 1930, p. 210 doi: 10.1093 / mnras / 91.1.210 ( bibcode : 1930MNRAS..91..210P ).
- ^ G. van Biesbroeck: Observations of comets at the Yerkes Observatory. In: The Astronomical Journal. Vol. 41, 1930, pp. 1-4 doi: 10.1086 / 105006 ( bibcode : 1930AJ ..... 41 .... 1V ).
- ^ G. van Biesbroeck: Comet Notes. In: Popular Astronomy. Vol. 38, 1930, p. 439 ( bibcode : 1930PA ..... 38..439V ).
- ↑ C / 1930 L1 (Forbes) in the Small-Body Database of the Jet Propulsion Laboratory (English).
- ↑ A. Vitagliano: SOLEX 11.0. Archived from the original on September 18, 2015 ; accessed on May 2, 2014 .
- ^ E. Everhart, N. Raghavan: Changes in Total Energy for 392 Long-Period Comets, 1800-1970. In: The Astronomical Journal. Vol. 75, 1970, pp. 258-272 doi: 10.1086 / 110974 ( bibcode : 1970AJ ..... 75..258E ).