C/1861 G1 (Thatcher)

C/1861 G1 (Thatcher)
Discovery
Discovered byA. E. Thatcher
Discovery date5 April 1861
Designations
1861 I
Orbital characteristics
Epoch25 May 1861 (JD 2400920.5)
Observation arc149 days
Number of
observations		187
Orbit typeLong period comet
Aphelion~112 AU
Perihelion0.921 AU (1861)
0.917 AU (2283)
Semi-major axis56.3 AU
Eccentricity0.983
Orbital period422 years
Inclination79.773°
31.867°
Argument of
periapsis		213.45°
Mean anomaly–0.023°
Last perihelion3 June 1861
Next perihelion2283
TJupiter0.304

Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 422-year orbit that is expected to return around 2283. It was discovered by A. E. Thatcher. It is responsible for the April Lyrid meteor shower. Carl Wilhelm Baeker also independently found this comet. The comet passed about 0.335 AU (50.1 million km; 31.1 million mi) from the Earth on 5 May 1861 and last came to perihelion (closest approach to the Sun) on 3 June 1861.

C/1861 G1 is listed as a long-period "non-periodic comet" because it has not yet been observed at two perihelion passages. When it is seen to come back around 2283, it should receive the P/ designation.

The comet is the parent body of the April Lyrids meteor shower.

See also

References

  1. ↑ Horizons output. "Barycentric Osculating Orbital Elements for Thatcher (C/1861 G1) at epoch 1900". Retrieved 26 August 2023. (Solution using the Solar System's barycenter (Sun+Jupiter). Select Ephemeris Type:Elements and Center:@0)
    (PR= 1.54E+05 / 365.25 = 422 years)
  2. 1 2 Horizons output. "2283 Perihelion for Comet C/1861 G1 (Thatcher)". Retrieved 7 August 2020. (Observer Location:@sun Perihelion occurs when deldot flips from negative to positive)
  3. 1 2 "C/1861 G1 (Thatcher) – JPL Small-Body Database Lookup". ssd.jpl.nasa.gov. Jet Propulsion Laboratory. Retrieved 21 April 2012.
  4. ↑ T. R. Arter; I. P. Williams (1997). "The mean orbit of the April Lyrids" (PDF). Monthly Notices of the Royal Astronomical Society. 289 (3): 721–728. Bibcode:1997MNRAS.289..721A. doi:10.1093/mnras/289.3.721.
  5. ↑ P. Jenniskens (2015). Meteor Showers and their Parent Comets. Cambridge University Press. p. 80. doi:10.1017/CBO9781316257104. ISBN 978-1-316-25710-4.
  6. ↑ M. Hajduková; L. Neslušan (2021). "Modeling the meteoroid streams of comet C/1861 G1 (Thatcher), Lyrids". Planetary and Space Science. 203 105246. Bibcode:2021P&SS..20305246H. doi:10.1016/j.pss.2021.105246.