C/1861 G1 (Thatcher)

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C/1861 G1 (Thatcher)
Discovered byA. E. Thatcher
Discovery dateApril 5, 1861
1861 I
Orbital characteristics
EpochJD 2400920.5
(May 25, 1861)
Orbit typeLong period comet
Aphelion110 AU
(beyond Eris)
Perihelion0.9207 AU
Semi-major axis55.6 AU
Orbital period415 a
Last perihelion1861-Jun-03[1]
Next perihelion2283 ±5[2]

Comet C/1861 G1 (Thatcher) is a long-period comet with roughly a 415-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.[3] 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 1861-May-05 and last came to perihelion (closest approach to the Sun) on 1861-Jun-03.[1]

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[edit]


  1. ^ a b "JPL Small-Body Database Browser: C/1861 G1 (Thatcher)". Jet Propulsion Laboratory. Retrieved 2012-04-21.
  2. ^ Horizons output. "Observer Table for Comet C/1861 G1 (Thatcher)". Retrieved 2020-08-07. (Observer Location:@sun Perihelion occurs when deldot flips from negative to positive)
  3. ^ 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.

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