A quasi-Hilda comet (QHC) is a Jupiter-family comet that interacts strongly with Jupiter and undergoes extended temporary capture by it. These comets are associated with the Hilda asteroid zone in the 3:2 inner mean-motion resonance with Jupiter. Typically, asteroids in this zone have a semimajor axis between 3.70 and 4.20 AU, eccentricities below 0.30, and inclinations of no more than 20°. Comets can be temporarily perturbed into this group and then perturbed back out again. Eight percent of the comets that leave the 3:2 resonance end up impacting Jupiter.

Known quasi-Hilda comets These numbered comets belong to the group of quasi-Hilda comets:

Full Name MPC designations Nucleus radii Aphelion (Q) Eccentricity Inclination Perihelion date Ref 36P/Whipple P/1925 QDP/1933 U1P/1940 R1 2.55 km 5.27 0.261 9.92 2011-12-29 74P/Smirnova–Chernykh P/1967 EUP/1975 E2 2.23 km 4.78 0.147 6.65 2009-07-26 82P/Gehrels P/1975 U1P/1984 P1 0.71 km 4.65 0.122 1.12 2010-01-12 111P/Helin–Roman–Crockett P/1989 A2 0.46–1.39 km 4.61 0.140 4.23 2013-01-30 117P/Helin–Roman–Alu P/1989 T2 16.4 km 5.13 0.253 8.69 2014-03-28 129P/Shoemaker–Levy P/1991 C1P/1996 U1 1.65 km 4.85 0.170 3.29 2014-02-07 135P/Shoemaker–Levy P/1992 G2P/1998 B1 1.38 km 4.93 0.289 6.05 2014-11-01 147P/Kushida–Muramatsu P/1993 X1P/2000 T2 0.22 km 4.85 0.276 2.36 2008-09-22 212P/NEAT 0.85 km 6.20 0.579 22.4 2008-12-03 215P/NEAT P/2002 O8P/2009 B5 1.825 km 4.83 0.200 12.7 2010-06-06 228P/LINEAR 2.41 km 4.89 0.176 7.91 2011-08-26 231P/LINEAR–NEAT P/2009 X1 – 5.01 0.246 12.3 2011-05-16 246P/NEAT P/2004 F3P/2010 V2 1.01 km 5.17 0.286 15.9 2013-01-28 1.7 km 5.04 0.188 5.81 2021-10-24 7.75–10.05 km 5.08 0.279 15.6 2024-07-20 482P/PanSTARRS – 5.62 0.493 24.5 2023-06-01 484P/Spacewatch 1.7 km 5.39 0.438 14.5 2020-11-26 505P/Palomar – 5.38 0.317 11.5 2017-09-27

39P/Oterma was a quasi-Hilda before a close approach to Jupiter in 1963. 77P/Longmore falls outside of the bulk distribution because of its large eccentricity and inclination. Comet Shoemaker–Levy 9 impacted with Jupiter in 1994.

Unnumbered comets and asteroids claimed to be quasi-Hilda objects (some of which were detected with cometary activity) are the following:

D/1977 C1 (Skiff–Kosai) (Catalina)

P/2010 H2 (Vales)

References