21P/Giacobini–Zinner

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21P/Giacobini–Zinner
Semi-major axis
3.492 AU
Eccentricity0.7110
Orbital period6.52 yr
Inclination32.050°
Last perihelion2018-Sep-10[1][2]
February 11, 2012[3]
July 2, 2005[3]
Next perihelion2025-Mar-25[3][4]
Earth MOID0.018 AU (2,700,000 km)[1]
Physical characteristics
Dimensions2 km[1]

Comet Giacobini–Zinner (officially designated 21P/Giacobini–Zinner) is a

periodic comet in the Solar System. It was discovered by Michel Giacobini, who observed it in the constellation of Aquarius on December 20, 1900. It was recovered two orbits later by Ernst Zinner, while he was observing variable stars near Beta Scuti
on October 23, 1913.

The

Giacobinids meteor shower (also known as the Draconids). The comet currently has a minimum orbit intersection distance to Earth of 0.035 AU (5,200,000 km; 3,300,000 mi).[1]

Giacobini–Zinner was the target of the International Cometary Explorer spacecraft, which passed through its plasma tail on September 11, 1985. Earlier in the same month the comet was observed by the Pioneer Venus Orbiter[6] In addition, Japanese space officials considered redirecting the Sakigake interplanetary probe toward a 1998 encounter with Giacobini–Zinner, but that probe lacked the propellant for the necessary maneuvers and the project was abandoned.

During the apparition of 2018, the optical spectra have revealed the comet is depleted in carbon-chain molecules and carbon dioxide, likely indicating its origin in relatively warm portion of the Solar system.[7]

References

  1. ^ a b c d e "JPL Small-Body Database Browser: 21P/Giacobini–Zinner" (last observation:2013-04-01). Jet Propulsion Laboratory. Retrieved 2016-01-10.
  2. Syuichi Nakano (2012-02-05). "21P/Giacobini-Zinner (NK 2191)"
    . OAA Computing and Minor Planet Sections. Retrieved 2012-02-18.
  3. ^ a b c MPC
  4. ^ "Horizons Batch for 21P/Giacobini-Zinner (90000322) on 2025-Mar-25" (Perihelion occurs when rdot flips from negative to positive). JPL Horizons. Retrieved 2021-04-10. (JPL#K182/14 Soln.date: 2021-Mar-23)
  5. ^ King, Bob (29 August 2018). "Comet 21P/Giacobini-Zinner Shines in September – Sky & Telescope". Sky & Telescope. Retrieved 15 September 2018.
  6. ISBN 9780387493268
    .
  7. doi:10.3847/1538-3881/ab7d34
    .

External links


Numbered comets
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20D/Westphal 		21P/Giacobini–Zinner Next
22P/Kopff
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