82P/Gehrels

82P/Gehrels is a periodic comet that was discovered on 27 October 1975, by Tom Gehrels at the Palomar Mountain Observatory in California having a faint nuclear brightness of magnitude 17.^[2]

82P/Gehrels

Discovery[1]
Discovered by	Tom Gehrels
Discovery site	Palomar Observatory
Discovery date	27 October 1975
Designations
MPC designation	P/1975 U1 P/1984 P1
Alternative designations	Gehrels 3 1977 VII, 1985 IV, 1993 XIV 1975o, 1984l, 1992v
Orbital characteristics[2][3]
Epoch	25 February 2023 (JD 2460000.5)
Observation arc	44.56 years
Number of observations	149
Aphelion	4.638 AU
Perihelion	3.629 AU
Semi-major axis	4.133 AU
Eccentricity	0.12207
Orbital period	8.403 years
Inclination	1.1259°
Longitude of ascending node	239.25°
Argument of periapsis	226.43°
Mean anomaly	200.37°
Last perihelion	28 June 2018[4][5]
Next perihelion	14 November 2026[6]
TJupiter	3.027
Earth MOID	2.643 AU
Jupiter MOID	0.517 AU
Physical characteristics[7]
Dimensions	1.46 km (0.91 mi)
Comet total magnitude (M1)	7.6
Comet nuclear magnitude (M2)	16.4

Calculations based on the early sightings gave an estimated perihelion of 23 April 1975 and an orbital period of 8.11 years. It was observed by J. Gibson on its next predicted apparition in 1984, using the 122-cm Schmidt at Palomar, when he estimated the nuclear brightness at a very faint magnitude 20. It has since been observed in 1993, 2001 and 2010.^[8]

The object has been identified as a quasi-Hilda comet, which means it is near a 3:2 mean-motion resonance with the planet Jupiter.^[9] It fits the definition of an Encke-type comet with (T_Jupiter > 3; a < a_Jupiter).^[2] It has an estimated diameter of 1.46 km (0.91 mi).^[7]

On 15 August 1970 the comet passed 0.00143 AU (214,000 km; 133,000 mi) from Jupiter.^[2]

See also

• Comet Gehrels
  • C/1972 F1 (Gehrels)
  • 64P/Swift–Gehrels
  • 78P/Gehrels 2
  • 90P/Gehrels 1
  • 270P/Gehrels
• List of numbered comets