Damocloids are a class of minor planets such as 5335 Damocles and 1996 PW that have Halley-type or long-period highly eccentric orbits typical of periodic comets such as Halley's Comet, but without showing a cometary coma or tail. David Jewitt defines a damocloid as an object with a Jupiter Tisserand invariant (T_J) of 2 or less,^[1][a] while Akimasa Nakamura defines this group with the following orbital elements:^[2]

• q < 5.2 AU, a > 8.0 AU, and e > 0.75,
• or alternatively, i > 90°

However, this definition that does not focus on Jupiter excludes objects such as (127546) 2002 XU₉₃, 2003 WG₁₆₆, and 2004 DA₆₂.^[3]

Using the Tisserand's parameter with respect to Jupiter of 2 or less, there are currently 220 damocloid candidates as of January 2022^[update].^[4] Of these objects, 189 have orbital observation arcs greater than 30 days providing reasonably decent orbits.^[1][5] Their average radius is eight kilometers assuming an albedo of 0.04. The albedos of four damocloids have been measured, and they are among the darkest objects known in the Solar System.^{[citation needed]} Damocloids are reddish in color, but not as red as many Kuiper-belt objects or centaurs. Other damocloids include: 2013 BL76, 2012 DR30, (528219) 2008 KV42, (65407) 2002 RP120, and 20461 Dioretsa.

Retrograde objects such as Halley's Comet and damocloid 343158 Marsyas can have relative velocities to Earth of 81 km/s (290,000 km/h).^[6]

Origin

Damocloids are thought to be nuclei of Halley-type comets that have lost all their volatile materials due to outgassing and become dormant. Such comets probably originate from the Oort cloud. This hypothesis is strengthened by the fact that a number of objects thought to be damocloids (and assigned minor-planet provisional designations) subsequently showed a coma and were confirmed to be comets: C/2001 OG₁₀₈ (LONEOS), C/2002 CE₁₀ (LINEAR), C/2002 VQ₉₄ (LINEAR), C/2004 HV₆₀ (Spacewatch) and possibly others. Another strong indication of cometary origin is the fact that some damocloids have retrograde orbits, unlike any other minor planets. (Objects with an inclination beyond 90 degrees up to 180 degrees are in a retrograde orbit and orbit in the opposite direction of other objects.)

List

As of August 2021^[update] this list from the JPL SBDB contains 20 numbered and 268 unnumbered bodies that meet Akimasa Nakamura's criteria for being classified as a damocloid, that is, either a retrograde orbit, or the following orbital elements: q < 5.2 AU, a > 8.0 AU, and e > 0.75 (also see § top). Tisserand's parameter with respect to Jupiter (T_Jupiter) is also given.^[a] Akimasa Nakamura's criteria and a T_Jupiter of less than two are largely equivalent as only a few listed bodies do not meet the defined T_Jupiter threshold. Most damocloids are also listed on MPC's list of other unusual minor planets.^[7] The orbital data is sourced from JPL-numbered and -unnumbered element files.^[8] The list includes A/-designated objects (introduced in 2017) that were mistakenly identified as a comet, but are actually minor planets. However it excludes hyperbolic bodies such as A/2019 G4 as well as 1I/ʻOumuamua and 2I/Borisov, two interstellar objects.

This section needs to be updated. Please help update this article to reflect recent events or newly available information. (October 2023)

Designation	a (AU)	e	i (°)	Orbital criteria and classes				q (AU)	Q (AU)	Unusual	Catalog	Refs
				Cls	Retro	TJupiter[a]	TJ ≤ 2
5335 Damocles	11.85	0.866	61.6	CEN	—	1.158	Y	1.59	22.11	—	LoMP	MPC · JPL
(15504) 1999 RG33	9.37	0.774	35	CEN	—	1.948	Y	2.12	16.63	unusual	LoMP	MPC · JPL
20461 Dioretsa	23.88	0.901	160.4	CEN	Y	-1.534	Y	2.37	45.39	unusual	LoMP	MPC · JPL
(65407) 2002 RP120	53.66	0.954	119.3	TNO	Y	-0.844	Y	2.46	104.86	unusual	LoMP	MPC · JPL
(154783) 2004 PA44	14.23	0.76	3.3	CEN	—	2.513	—	3.42	25.04	unusual	LoMP	MPC · JPL
(330759) 2008 SO218	8.12	0.562	170.3	CEN	Y	-1.397	Y	3.56	12.69	unusual	LoMP	MPC · JPL
(336756) 2010 NV1	278.33	0.966	140.7	TNO	Y	-2.903	Y	9.42	547.23	—	LoMP	MPC · JPL
(342842) 2008 YB3	11.58	0.442	105.1	CEN	Y	-0.246	Y	6.47	16.7	—	LoMP	MPC · JPL
343158 Marsyas	2.53	0.807	154.4	NEO	Y	1.317	Y	0.49	4.57	—	LoMP	MPC · JPL
(434620) 2005 VD	6.67	0.251	172.9	CEN	Y	-1.394	Y	5	8.34	unusual	LoMP	MPC · JPL
(459870) 2014 AT28	10.9	0.401	165.5	CEN	Y	-2.090	Y	6.53	15.27	—	LoMP	MPC · JPL
(468861) 2013 LU28	191.63	0.954	125.3	TNO	Y	-2.069	Y	8.74	374.53	—	LoMP	MPC · JPL
(471325) 2011 KT19	35.7	0.33	110.2	TNO	Y	-1.560	Y	23.9	47.5	—	LoMP	MPC · JPL
514107 Kaʻepaokaʻawela	5.13	0.378	163.1	other	Y	-0.745	Y	3.19	7.07	—	LoMP	MPC · JPL
(518151) 2016 FH13	24.54	0.615	93.6	CEN	Y	-0.005	Y	9.45	39.62	—	LoMP	MPC · JPL
(523797) 2016 NM56	71.46	0.853	144	TNO	Y	-3.061	Y	10.53	132.38	—	LoMP	MPC · JPL
(523800) 2017 KZ31	54.3	0.798	161.7	TNO	Y	-3.601	Y	10.96	97.63	—	LoMP	MPC · JPL
(528219) 2008 KV42	42.03	0.497	103.4	TNO	Y	-1.021	Y	21.15	62.92	—	LoMP	MPC · JPL
(582301) 2015 RM306	246.87	0.954	176	TNO	Y	-4.117	Y	11.46	482.29	—	LoMP	MPC · JPL
(585899) 2020 HM98	83.6	0.841	137.9	TNO	Y	-3.151	Y	13.26	153.94	—	LoMP	MPC · JPL
(612093) 1999 LE31	8.17	0.468	151.5	CEN	Y	-1.309	Y	4.35	11.99	—	LoMP	MPC · JPL
1996 PW	265.49	0.991	30.1	TNO	—	1.708	Y	2.49	528.5	unusual	—	MPC · JPL
1997 MD10	26.49	0.943	59.4	CEN	—	0.960	Y	1.51	51.47	—	—	MPC · JPL
1998 QJ1	11.24	0.815	23.7	CEN	—	2.023	—	2.08	20.41	unusual	—	MPC · JPL
1998 WU24	15.13	0.907	42.5	CEN	—	1.404	Y	1.41	28.85	—	—	MPC · JPL
1999 XS35	17.77	0.948	19.5	NEO	—	1.405	Y	0.93	34.62	—	—	MPC · JPL
2000 AB229	52.32	0.956	68.2	TNO	—	0.790	Y	2.31	102.33	unusual	—	MPC · JPL
2000 DG8	10.77	0.793	129.3	CEN	Y	-0.627	Y	2.23	19.31	unusual	— Zdroj:https://en.wikipedia.org?pojem=Damocloid_asteroid Text je dostupný za podmienok Creative Commons Attribution/Share-Alike License 3.0 Unported; prípadne za ďalších podmienok. Podrobnejšie informácie nájdete na stránke Podmienky použitia.  Navigácia: Veda > Analytika Antropológia Aplikované vedy Bibliometria Dejiny vedy Encyklopédie Filozofia vedy Forenzné vedy Humanitné vedy Knižničná veda Kryogenika Kryptológia Kulturológia Literárna veda Medzidisciplinárne oblasti Metódy kvantitatívnej analýzy Metavedy Metodika Metodológia vedy Náboženstvo a veda Náučná literatúra Podvody vo vede Popularizácia vedy Potravinárstvo Prírodné vedy Pseudoveda Scientometria Spoločenské vedy Teórie Teatrológia Technické vedy Technika Terminológia Umenie Výskum Veda Veda a technika podľa štátu Veda a technika podľa kontinentu Veda a technika podľa roka Veda v kozme Vedci Vedecká literatúra Vedecké databázy Vedecké experimenty Vedecké konferencie Vedecké metódy Vedecké ocenenia Vedecké organizácie Vedecké parky Vedeckí spisovatelia Vzdelávanie Záhady Príbuzné výrazy: Text je dostupný za podmienok Creative Commons Attribution/Share-Alike License 3.0 Unported; prípadne za ďalších podmienok. Podrobnejšie informácie nájdete na stránke Podmienky použitia. www.astronomia.sk | www.biologia.sk | www.botanika.sk | www.dejiny.sk | www.economy.sk | www.elektrotechnika.sk | www.estetika.sk | www.farmakologia.sk | www.filozofia.sk | Fyzika | www.futurologia.sk | www.genetika.sk | www.chemia.sk | www.lingvistika.sk | www.politologia.sk | www.psychologia.sk | www.sexuologia.sk | www.sociologia.sk | www.veda.sk I www.zoologia.sk