C/1930 L1 (Forbes)
| Discovery[1] | |
|---|---|
| Discovered by | Alexander F. I. Forbes |
| Discovery site | Cape Town, South Africa |
| Discovery date | 31 May 1930 |
| Designations | |
| 1930e[2] 1930 V | |
| Orbital characteristics[3][4] | |
| Epoch | 6 June 1930 (JD 2426133.5) |
| Observation arc | 49 days |
| Number of observations | 54 |
| Perihelion | 1.1528 AU |
| Eccentricity | ~1.000 |
| Orbital period | <270,000 years (inbound) |
| Inclination | 97.0912° |
| 279.265° | |
| Argument of periapsis | 320.966° |
| Last perihelion | 10 May 1930 |
| Physical characteristics | |
| 9.0 (1930 apparition) | |
Comet Forbes, formally designated as C/1930 L1, is a parabolic comet that was only observed through optical telescopes in the year 1930.
Observational history
[edit]The comet was discovered by Alexander F. I. Forbes as a 9th-magnitude object on the early morning skies of 31 May 1930. It was the fifth new comet of the year and the second of three comets he discovered overall.[5] He immediately informed the Union Observatory in Johannesburg after an exact position was determined about two days later.[1][6]
The comet was already on its outbound flight since it reached perihelion on 10 May 1930, about three weeks before discovery, but was still approaching Earth at the time, allowing it to be regularly observed from Johannesburg until the end of June.[7] It was only visible in the southern hemisphere until June 23, when first northern observations were recorded by the National Observatory in Athens, Greece.[8]
George van Biesbroeck made his first observations of the comet from the Yerkes Observatory on June 21, with Georg von Struve following suit from the Berlin Observatory shortly afterwards,[9] however by that time it rapidly faded away from magnitude 11 to 15 by the end of the month, though a short tail was reported.[6] Van Biesbroeck continued his photographic observations of the comet until July 17, and its last known position was recorded on July 21.[10]
Orbit
[edit]In 1952, Austrian astronomer Erich Senftl of the Vienna Observatory was able to calculate a retrograde parabolic orbit based from 54 observations over 49 days, which is inclined to 97 degrees from the ecliptic.[11] It reached perihelion at a distance of 1.12 AU (168 million km) on 10 May 1930, and made its closest approach to Earth at a distance of 0.37 AU (55 million km) on June 21. Due to limited data acquired, it is unknown whether it remains bound to the Solar System or it was ejected into interstellar space.[4]
References
[edit]- ^ a b E. Strömgren (4 June 1930). "New Comet Forbes (1930e)". Central Bureau for Astronomical Telegrams. 285.
- ^ "Comet Names and Designations". International Comet Quarterly. Retrieved 12 December 2024.
- ^ "C/1930 L1 (Forbes) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 12 December 2024.
- ^ a b A. Vitagliano. "SOLEX 12.1". solexorb.it. Retrieved 9 July 2020.
- ^ C. Plug. "Forbes, Mr. Alexander Forbes Irvine (astronomy)". Biographical Database of Southern African Science. Retrieved 2 August 2019.
- ^ a b G. van Biesbroeck (1930). "Comet Notes". Popular Astronomy. 38: 439. Bibcode:1930PA.....38..439V.
- ^ "Photographic Observations of Comet 1930e (Forbes)". Circular of the Union Observatory Johannesburg. 84: 172. 1931. Bibcode:1931CiUO...84..172.
- ^ S. Plakidis (1930). "Observations of the Comet Forbes (1930e), made with the Doridis Refractor (Gautier 40 cm.) of the National Observatory of Athens" (PDF). Monthly Notices of the Royal Astronomical Society. 91 (1): 210. doi:10.1093/mnras/91.1.210.
- ^ G. van Biesbroeck (1930). "Observations of comets at the Yerkes Observatory". The Astronomical Journal. 41 (949): 1–4. Bibcode:1930AJ.....41....1V. doi:10.1086/105006.
- ^ A. C. D. Crommelin (1931). "Report on Comets in 1930" (PDF). Monthly Notices of the Royal Astronomical Society. 91 (4): 376–380. doi:10.1093/mnras/91.4.376.
- ^ G. Merton (1953). "Comets (1952)" (PDF). Monthly Notices of the Royal Astronomical Society. 113 (3): 386–392. doi:10.1093/mnras/113.3.386.
External links
[edit]- C/1930 L1 at the JPL Small-Body Database
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