C/1861 G1 (Thatcher)

C/1861 G1 (Thatcher)
Discovery
Discovered byA. E. Thatcher
Discovery dateApril 5, 1861
Designations
1861 I
Orbital characteristics[1][2][3]
Observation arc149 days
Number of
observations		187
Orbit typeLong period comet
Aphelion112 AU
(beyond Eris)
Perihelion0.921 AU (1861)
0.917 AU (2283)
Semi-major axis56.3 AU
Eccentricity0.983
Orbital period422 yr (barycentric)
Inclination79.77°
Last perihelion1861-Jun-03
Next perihelion2283 ±5

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.[4] 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.[3]

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,[2] 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 2023-08-26. (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. ^ a b Horizons output. "2283 Perihelion for Comet C/1861 G1 (Thatcher)". Retrieved 2020-08-07. (Observer Location:@sun Perihelion occurs when deldot flips from negative to positive)
  3. ^ a b "JPL Small-Body Database Browser: C/1861 G1 (Thatcher)". Jet Propulsion Laboratory. Retrieved 2012-04-21.
  4. ^ Arter, T. R.; Williams, I. P. (1997). "The mean orbit of the April Lyrids". Monthly Notices of the Royal Astronomical Society. 289 (3): 721–728. Bibcode:1997MNRAS.289..721A. doi:10.1093/mnras/289.3.721.