D/1766 G1 (Helfenzrieder)
| Discovery | |
|---|---|
| Discovered by | Johann E. Helfenzrieder |
| Discovery site | Dillingen, Germany |
| Discovery date | 1 April 1766 |
| Designations | |
| 1766 II[1] | |
| Orbital characteristics[2] | |
| Epoch | 3 May 1766 (JD 2366200.5) |
| Observation arc | 24 days |
| Number of observations | 22 |
| Aphelion | 4.923 AU |
| Perihelion | 0.406 AU |
| Semi-major axis | 2.665 AU |
| Eccentricity | 0.84763 |
| Orbital period | ~4.35 years |
| Inclination | 7.865° |
| 76.263° | |
| Argument of periapsis | 178.699° |
| Mean anomaly | 1.154° |
| Last perihelion | 27 April 1766 (last known observation) 16 November 2021[3] (calculated) |
| Next perihelion | 16 March 2026[3] (calculated) |
| TJupiter | 2.705 |
| Physical characteristics[4] | |
Mean radius | ~3.0–8.7 km (1.9–5.4 mi) |
| Comet nuclear magnitude (M2) | ~4.5–6.8 |
| 4.0–5.0[5] (1766 apparition) | |
Comet Helfenzrieder, also known by its modern designation D/1766 G1, is a Jupiter-family comet that was first seen between April and May 1766. The comet was never recovered on its next apparitions and was subsequently considered lost.
Orbit
[edit]Uncertainties in orbital calculations prevented the comet from being recovered on its next apparitions after 1766.[6] Between 1766 and 1773, Alexandre Guy Pingré made the first parabolic orbits for comet Helfenzrieder, where his computations revealed a perihelion date of 17 April 1766 at a distance of 0.637 AU (95.3 million km), though he still considered this calculation uncertain.[5] He later revised his calculations in 1784, where he determined that the comet might had reached perihelion on 23 April 1766 at a distance of 0.33 AU (49 million km).[7]
Johann Karl Burckhardt was the first astronomer to determine that Helfenzrieder has a short period elliptical orbit in 1821, where he calculated the comet's orbital period to 5.02 years. In 1915, Carl Wilhelm Wirtz noted that three years before discovery, the comet made a close encounter with Jupiter on 11 November 1763 at a distance of 0.03 AU (4.5 million km).[8]
The comet is likely a member of the Hephaistos group,[9] a subset of the larger Taurid complex that also include 2P/Encke, 169P/NEAT, and P/2003 T12 (SOHO).[10] Of all the near-Earth comets, Helfenzrieder has the highest probability of impacting Earth, however it is not clear if this comet still existed to the present day.[4]
In March 2017, David A. J. Seargent identified that the asteroid 2017 DW108 has an orbit very similar to D/1766 G1 (Helfenzrieder), however the link between two objects is not yet definitely confirmed.[11]
References
[edit]- ↑ "Comet Names and Designations". International Comet Quarterly. Retrieved 29 May 2025.
- ↑ "D/1766 G1 (Helfenzrieder) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 29 May 2025.
- 1 2 S. Yoshida. "D/1766 G1 (Helfenzrieder)". www.aerith.net. Retrieved 29 May 2025.
- 1 2 M. Beech; K. Gauer (2002). "Cosmic Roulette: Comets In The Main Belt Asteroid Region" (PDF). Earth, Moon, and Planets. 88 (4): 211–221. Bibcode:2002EM&P...88..211B. doi:10.1023/A:1019813115494.
- 1 2 G. W. Kronk; M. Meyer; D. A. J. Seargent (1999). Cometography: A Catalog of Comets. Vol. 1: Ancient–1799. Cambridge University Press. pp. 440–442. ISBN 978-0-521-58504-0.
- ↑ P. M. Shober; G. Tancredi; J. Vaubaillon; H. A. R. Devillepoix; S. Deam; et al. (2024). "Comparing the dynamics of Jupiter-family Comets and comet-like fireballs" (PDF). Astronomy & Astrophysics. 687: 181–210. doi:10.1051/0004-6361/202449635.
- ↑ A. G. Pingré (1784). Cométographie Ou Traité Historique Et Théorique Des Comètes (in French). Vol. 2. pp. 76–82.
- ↑ C. W. Wirtz (1915). "Der kurzperiodische Komet 1766 II". Astronomische Nachrichten (in German). 201 (4). doi:10.1002/asna.19152010402.
- ↑ D. Steel; D. Asher (1994). "P/Helfenzrieder (1766 II) and the Hephaistos group of Earth-crossing asteroids". The Observatory. 114: 223–226. Bibcode:1994Obs...114..223S.
- ↑ I. Ferrín; V. Orofino (2021). "Taurid Complex Smoking Gun: Detection of Cometary Activity". Planetary and Space Science. 207 105306. arXiv:2011.13078. doi:10.1016/j.pss.2021.105306.
- ↑ D. A. J. Seargent (1 March 2017). "Asteroid 2017 DW108 & D/1766 G1". Groups.io. Retrieved 29 May 2025.
External links
[edit]- D/1766 G1 at the JPL Small-Body Database
- D/1766 G1 at Gary W. Kronk's Cometography
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