617 Patroclus

Last updated
617 Patroclus
617 Patroclus Hubble.jpg
Hubble Space Telescope image composite of Patroclus and its companion Menoetius, taken in 2018
Discovery [1]
Discovered by A. Kopff
Discovery site Heidelberg Obs.
Discovery date17 October 1906
Designations
(617) Patroclus
Pronunciation /pəˈtrkləs/ [2]
Named after
Πάτροκλος Patroklos
(Greek mythology) [3]
1906 VY ·1941 XC
1962 NB
Jupiter trojan [1] [4] [5]
Trojan [6] [7]  · background [7]
Adjectives Patroclean /pætrəˈklən/ [8]
Orbital characteristics [4]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc 19.15 yr (6,993 d)
Aphelion 5.9376 AU
Perihelion 4.4959 AU
5.2167 AU
Eccentricity 0.1382
11.92 yr (4,352 d)
170.39°
0° 4m 57.72s / day
Inclination 22.047°
44.354°
308.15°
Known satellites 1 (Menoetius) [9]
Jupiter  MOID 0.1966 AU
TJupiter 2.8360
Physical characteristics
Dimensions127  km × 117  km × 98  km (primary only) [10]
Mean diameter
113±3 km(primary only) [10]
140.36±0.87  km [11]
140.85±3.37 km [12]
140.92±4.7 km [13]
143.14±8.37 km [14]
154 km [10]
Volume 1.36×106 km3 [10]
Mass (1.36±0.11)×1018  kg [14]
1.20×1018 kg [10]
Mean density
0.88±0.17 g/cm3 [14] [10]
40 h(at least; dated) [15]
102.8 h [16]
102 h [17]
103.02±0.40 h [18]
103.5±0.3 h [19]
0.047±0.003 [11] [12] [13]
D (Tholen) [20]
C0 (Barucci) [20]
D (Tedesco) [20]
U–B = 0.215±0.045 [20]
B–V = 0.710±0.050 [21]
V–R = 0.420±0.030 [21]
V–I = 0.830±0.020 [21]
8.19 [4] [11] [12] [13] [5]

    617 Patroclus ( /pəˈtrkləs/ pə-TROH-kləs) is a large binary Jupiter trojan asteroid. It is a dark D-type asteroid and a slow rotator, due to the 103-hour orbital period of its two components. It is one of five Jovian asteroids targeted by the Lucy space probe, and is scheduled for a flyby in 2033.

    Contents

    Patroclus was discovered on 17 October, 1906, by astronomer August Kopff at the Heidelberg Observatory in Germany, and was named after Patroclus in Greek mythology. [1] It was the second trojan to be discovered and the only member of the Trojan camp named after a Greek figure, as the convention of naming one 'camp' after Greek figures of the Trojan War and the other after Trojan figures had not yet been established. [3]

    Patroclus was long thought to be one of the largest Jupiter trojans, with a diameter on the order of 150 km. However, in 2001 it was discovered to be a binary asteroid of two similarly sized objects. The name Patroclus is now assigned to the larger component, some 110115 km in diameter, while the secondary, slightly smaller at 100105 km in diameter, has been named Menoetius ( /mɪˈnʃəs/ mə-NEE-shəs). [lower-alpha 1] This was the first discovery of a binary trojan asteroid. [9]

    Orbit

    Patroclus orbits in Jupiter's trailing Lagrangian point, L5, [9] in an area called the Trojan camp after one of the sides in the legendary Trojan War (the other node, at the L4 point, is called the "Greek camp").

    It orbits the Sun at a distance of 4.5–5.9  AU once every 11 years and 11 months (4,353 days). Its orbit has an eccentricity of 0.14 and an inclination of 22° with respect to the ecliptic. [4] The asteroid's observation arc begins at the discovering Heidelberg Observatory in November 1906, about 3 weeks after its official discovery observation. [1]

    Binary system

    Hubble images of Patroclus and Menoetius orbiting each other, from May to June 2017 Patroclus-Menoetius-orbit.gif
    Hubble images of Patroclus and Menoetius orbiting each other, from May to June 2017
    Artist's conception of Patroclus and Menoetius orbiting around their center of mass, occasionally eclipsing one another PatroclusMenoetius-binary.gif
    Artist's conception of Patroclus and Menoetius orbiting around their center of mass, occasionally eclipsing one another
    Artist's impression of the Patroclus-Menoetius binary system PatroclusMenoetius-artists-impression.png
    Artist's impression of the Patroclus-Menoetius binary system
    Menoetius
    617PatroclusMenoetius20131021.jpg
    Plot of the results of the multi-chord stellar occultation by 617 Patroclus and Menoetius
    Discovery
    Discovery date2001
    Designations
    Pronunciation /mɪˈnʃəs/
    Named after
    Menoetius (Greek mythology)
    Adjectives Menoetian /mɪˈnʃən/ [22] )
    Orbital characteristics
    680±20 km [9]
    664.6 km [10]
    102.8 h
    Satellite of Patroclus
    Physical characteristics
    Dimensions117 km × 108 km × 90 km [10]
    Mean diameter
    104±3 km [10]

      In 2001, it was discovered that Patroclus is a binary system, made up of two components with of roughly similar size. [9] [23] [24] It is one of 6 binary Trojan asteroids believed to exist. In 2006, accurate measurements of the orbit from the Keck Laser guide star adaptive optics system were reported. [25]

      It was estimated [26] that the two components orbit around their center of mass in 4.283±0.004 days at a distance of 680±20 km in a roughly circular orbit. [9] Combining these observations with thermal measurements taken in 2000, the sizes of the components of the system were estimated at 106 km and 98 km, with an equivalent whole-system diameter of 145 km, [9] refined by later measurements from the Keck Observatory to approximately 122 km and 112 km for each partner, [27] and a co-orbital period of 103.5±0.3 hours (4.3125±0.0125 days). [25] [19]

      On 21 October 2013, both bodies occulted a magnitude 8.8 star as observed by a team of 41 observers stationed across the USA. Observation data put the orbital distance at the time of 664.6 km (with an unstated uncertainty), and give a size for the slightly larger component, which retains the name Patroclus with overall volume equivalent to a 113±3 kmdiameter sphere, with the smaller component now named Menoetius with a volume equivalent to a 104±3 kmdiameter sphere.

      Physical characteristics

      Lightcurves

      Since 1989, several rotational lightcurves of Patroclus have been obtained from photometric observations. Analysis of the best rated lightcurves gave a rotation period between 102.8 and 103.5 hours with a brightness amplitude of less than 0.1 magnitude ( U=2/3/ ). [16] [17] [18] [19] A low brightness variation typically indicates that a body has a nearly spheroidal shape. Its long rotation period makes it a slow rotator.

      Diameter and albedo

      According to the surveys carried out by the Infrared Astronomical Satellite IRAS and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the Patroclus system has an effective combined size between 140.36 and 140.92 kilometers in diameter and its surface has an albedo of 0.047. [11] [13] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0471 and a diameter of 140.92 kilometers based on an absolute magnitude of 8.19. [5]

      Composition

      Recent evidence suggests that the objects are icy like comets, rather than rocky like most asteroids. In the Tholen classification, Patroclus is a dark P-type asteroid. [5]

      Because the density of the components (0.88 g/cm³) is less than water and about one third that of rock, it was suggested that the Patroclus system, previously thought to be a pair of rocky asteroids, is more similar to a comet in composition. [25] It is suspected that many Jupiter trojans are in fact small planetesimals captured in the Lagrange point of the Jupiter–Sun system during the migration of the giant planets 3.9 billion years ago. This scenario was proposed by A. Morbidelli and colleagues in a series of articles published in May 2005 in Nature . [28]

      Exploration

      Animation of Lucy's trajectory around Sun

.mw-parser-output .legend{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .legend-color{display:inline-block;min-width:1.25em;height:1.25em;line-height:1.25;margin:1px 0;text-align:center;border:1px solid black;background-color:transparent;color:black}.mw-parser-output .legend-text{}
Lucy *
Sun *
Earth *
52246 Donaldjohanson  *
3548 Eurybates *
21900 Orus *
617 Patroclus Animation of Lucy's trajectory around Sun.gif
      Animation of Lucy's trajectory around Sun
        Lucy ·   Sun ·   Earth ·   52246 Donaldjohanson  ·  3548 Eurybates ·   21900 Orus ·   617 Patroclus
      Artist's impression of the Lucy spacecraft flying past the Patroclus-Menoetius system Lucy-PatroclusMenoetius-art.png
      Artist's impression of the Lucy spacecraft flying past the Patroclus-Menoetius system

      The Patroclus–Menoetius system is a scheduled target for Lucy , a flyby mission to multiple asteroids, mostly Jupiter trojans. [29]

      Name

      This minor planet was named after the legendary Greek hero Patroclus. Friend and lover of Achilles, he was killed by Hector during the Trojan War. (See 588 Achilles and 624 Hektor.) The name was proposed by Austrian astronomer Johann Palisa. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ( H 65 ). [3]

      In Greek and thus in Latin, Patroclus has all short vowels. Thus the expected English pronunciation would be with stress on the 'a', * /ˈpætrəkləs/ . However, Alexander Pope shifted the stress to the first 'o', /pəˈtrkləs/ , [2] a convention allowed in Latin poetry, [30] for metrical convenience in his verse translation of Homer, and this irregular pronunciation has become established in English.

      Patroclus and its moon Menoetius are the only objects in the Trojan camp to be named after Greek rather than Trojan characters. The naming conventions for the Jupiter trojans were not adopted until after Patroclus was named (similarly, the asteroid Hektor is the only Trojan character to appear in the Greek camp).

      Notes

      1. Buie (2015). Volume equivalent diameters based on derived ellipsods are: Patroclus: 113 km and Menoetius: 104 km, while for the combined system, a mean-diameter of 154 km is given. Measured by asteroid occultation. Alternative observations gave a combined diameter of 140 kilometers. Summary figures for (617) Patroclus at the LCDB.

      Related Research Articles

      Jupiter trojan Asteroid sharing the orbit of Jupiter

      The Jupiter trojans, commonly called Trojan asteroids or simply Trojans, are a large group of asteroids that share the planet Jupiter's orbit around the Sun. Relative to Jupiter, each Trojan librates around one of Jupiter's stable Lagrange points: either L4, existing 60° ahead of the planet in its orbit, or L5, 60° behind. Jupiter trojans are distributed in two elongated, curved regions around these Lagrangian points with an average semi-major axis of about 5.2 AU.

      588 Achilles

      Achilles is a large Jupiter trojan from the Greek camp. Achilles was the first Jupiter trojan to be discovered, and was discovered by Max Wolf at the Heidelberg Observatory in 1906. Wolf named the minor planet after the legendary hero Achilles from Greek mythology. The dark D-type asteroid measures approximately 133 kilometers in diameter which makes it one of the 10 largest Jupiter trojans. It has a rotation period of 7.3 hours and possibly a spherical shape.

      624 Hektor

      624 Hektor is the largest Jupiter trojan and the namesake of the Hektor family, with a highly elongated shape equivalent in volume to a sphere of approximately 225 to 250 kilometers diameter. It was discovered on 10 February 1907, by astronomer August Kopff at Heidelberg Observatory in southwest Germany, and named after the Trojan prince Hector, from Greek mythology. It has one small 12-kilometer sized satellite, Skamandrios, discovered in 2006.

      911 Agamemnon Jupiter trojan

      911 Agamemnon, provisional designation 1919 FD, is a large Jupiter trojan and a suspected binary asteroid from the Greek camp, approximately 168 kilometers in diameter. It was discovered on 19 March 1919, by German astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The dark D-type asteroid is one of the largest Jupiter trojans and has a rotation period of 6.6 hours. It is named after the Greek King Agamemnon, a main character of the Iliad.

      1404 Ajax

      1404 Ajax is a carbonaceous Jupiter trojan from the Greek camp, approximately 83 kilometers kilometers in diameter. It was discovered on 17 August 1936, by German astronomer Karl Reinmuth at Heidelberg Observatory in southern Germany, and named after the legendary warrior Ajax from Greek mythology. The assumed C-type asteroid belongs to the 40 largest Jupiter trojans and has a longer than average rotation period of 29.4 hours.

      1583 Antilochus is a large Jupiter trojan from the Greek camp, approximately 108 kilometers in diameter. It was discovered on 19 September 1950, by Belgian astronomer Sylvain Arend at Uccle Observatory in Belgium, and later named after the hero Antilochus from Greek mythology. The dark D-type asteroid belongs to the 20 largest Jupiter trojans and has a rotation period of 15.9 hours. It forms an asteroid pair with 3801 Thrasymedes.

      2759 Idomeneus is a dark Jupiter trojan from the Greek camp, approximately 55 kilometers in diameter. It was discovered on 14 April 1980, by American astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona, in the United States, and later named after Idomeneus from Greek mythology. The D-type asteroid from the Jovian background population belongs to the 80 largest Jupiter trojans. It is a suspected binary system and potentially a slow rotator with a rotation period of 479 hours.

      2797 Teucer is a large Jupiter trojan from the Greek camp, approximately 110 kilometers in diameter. It was discovered on 4 June 1981, by American astronomer Edward Bowell at the Anderson Mesa Station near Flagstaff, Arizona, in the United States. The dark D-type asteroid belongs to the 20 largest Jupiter trojans and has a rotation period of 10.15 hours. It was named after the Greek hero and great archer, Teucer.

      2920 Automedon is a large Jupiter trojan from the Greek camp, approximately 110 kilometers in diameter. It was discovered by American astronomer Edward Bowell at the Anderson Mesa station of the Lowell Observatory on 3 May 1981. The dark D-type asteroid has a rotation period of 10.22 hours and belongs to the 30 largest Jupiter trojans. It was named after the ancient Greek hero Automedon, the charioteer of Achilles.

      3063 Makhaon is a large Jupiter trojan from the Greek camp, approximately 114 kilometers in diameter. It was discovered on 4 August 1983, by Soviet astronomer Lyudmila Karachkina at the Crimean Astrophysical Observatory in Nauchnij, on the Crimean peninsula. The dark D-type asteroid is the principal body of the proposed Makhaon family and belongs to the 20 largest Jupiter trojans having a rotation period of 8.6 hours. It was named after the legendary healer Machaon from Greek mythology.

      12714 Alkimos is a large Jupiter trojan from the Greek camp, approximately 54 kilometers in diameter. It was discovered on 15 April 1991, by American astronomer couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California. The dark Jovian asteroid has a rotation period of 28.5 hours. It was named from Greek mythology after Alcimus, son of Ares and companion of Achilles.

      2363 Cebriones is a large Jupiter trojan from the Trojan camp, approximately 84 kilometers in diameter. It was discovered on 4 October 1977, by astronomers at the Purple Mountain Observatory in Nanking, China. The dark D-type asteroid is one of the 40 largest Jupiter trojans and has a rotation period of 20 hours. It was named after Cebriones, Hektor's charioteer from Greek mythology.

      1867 Deiphobus is a dark Jupiter trojan from the Trojan camp, approximately 123 kilometers (76 mi) in diameter. It was discovered on 3 March 1971, by Argentine astronomers Carlos Cesco and A. G. Samuel at the Leoncito Astronomical Complex in Argentina, and later named after the Trojan prince Deiphobus from Greek mythology. The dark D-type asteroid is one of the largest Jupiter trojans. It is a member of the Ennomos family and has a long rotation period of 58.66 hours.

      4063 Euforbo is a large Jupiter trojan from the Greek camp, approximately 100 kilometers in diameter. It was discovered on 1 February 1989, by Italian astronomers at the San Vittore Observatory near Bologna, Italy. The dark D-type asteroid is one of the 25 largest Jupiter trojans and has a rotation period of 8.8 hours. It was named after Euphorbus (Euforbo) from Greek mythology.

      '4501 Eurypylos is a Jupiter trojan from the Greek camp, approximately 46 kilometers in diameter. It was discovered on 4 February 1989 by Belgian astronomer Eric Elst at ESO's La Silla Observatory in Chile. The dark Jovian asteroid has a short rotation period of 6.1 hours. It was named after the Thessalian king Eurypylus from Greek mythology.

      2895 Memnon is a dark Jupiter trojan from the Trojan camp, approximately 56 kilometers in diameter. It was discovered on 10 January 1981, by American astronomer Norman Thomas at Lowell's Anderson Mesa Station near Flagstaff, Arizona, in the United States. The assumed C-type asteroid has a rotation period of 7.5 hours and belongs to the 80 largest Jupiter trojans. It was named after King Memnon from Greek mythology.

      1172 Äneas

      1172 Äneas is a large Jupiter trojan from the Trojan camp, approximately 140 kilometers in diameter. It was discovered on 17 October 1930, by astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The dark D-type asteroid is one of the largest Jupiter trojans and has a rotation period of 8.7 hours. It is named after the Trojan prince Aeneas, from Greek mythology.

      2223 Sarpedon is a dark Jupiter trojan from the Trojan camp, approximately 90 kilometers in diameter. It was discovered on 4 October 1977, by astronomers at the Purple Mountain Observatory near Nanking, China. The D-type asteroid belongs to the 30 largest Jupiter trojans and has a rotation period of 22.7 hours. It was named after the Lycian hero Sarpedon from Greek mythology.

      11509 Thersilochos is a Jupiter trojan from the Trojan camp, approximately 50 kilometers in diameter. It was discovered on 15 November 1990, by Belgian astronomer Eric Elst at the La Silla Observatory in northern Chile. The dark Jovian asteroid belongs to the 100 largest Jupiter trojans and has a rotation period of 17.4 hours. It was named after the Trojan warrior Thersilochus from Greek mythology.

      15094 Polymele

      15094 Polymele is a primitive Jupiter trojan from the Greek camp, approximately 21 kilometers in diameter. It is a target of the Lucy mission with a close fly by planned to occur in September 2027. It was discovered on 17 November 1999, by astronomers with the Catalina Sky Survey at Mount Lemmon Observatory, Arizona, in the United States. The P-type asteroid has a rotation period of 5.9 hours and possibly a spherical shape. It was named after Polymele from Greek mythology, the wife of Menoetius and the mother of Patroclus.

      References

      1. 1 2 3 4 "617 Patroclus (1906 VY)". Minor Planet Center. Retrieved 13 June 2018.
      2. 1 2 "Patroclus". Dictionary.com Unabridged. Random House.
      3. 1 2 3 Schmadel, Lutz D. (2007). "(617) Patroclus". Dictionary of Minor Planet Names – (617) Patroclus. Springer Berlin Heidelberg. p. 62. doi:10.1007/978-3-540-29925-7_618. ISBN   978-3-540-00238-3.
      4. 1 2 3 4 "JPL Small-Body Database Browser: 617 Patroclus (1906 VY)" (2017-06-14 last obs.). Jet Propulsion Laboratory . Retrieved 13 June 2018.
      5. 1 2 3 4 "LCDB Data for (617) Patroclus". Asteroid Lightcurve Database (LCDB). Retrieved 11 July 2017.
      6. "List of Jupiter Trojans". Minor Planet Center. 20 August 2016. Retrieved 11 July 2017.
      7. 1 2 "Asteroid (617) Patroclus – Proper elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 13 June 2018.
      8. Riggs (1972) The Christian poet in Paradise lost
      9. 1 2 3 4 5 6 7 Johnston, Wm. Robert (21 September 2014). "(617) Patroclus and Menoetius". johnstonsarchive.net. Retrieved 11 July 2017.
      10. 1 2 3 4 5 6 7 8 9 Buie, Marc W.; Olkin, Catherine B.; Merline, William J.; Walsh, Kevin J.; Levison, Harold F.; Timerson, Brad; et al. (March 2015). "Size and Shape from Stellar Occultation Observations of the Double Jupiter Trojan Patroclus and Menoetius". The Astronomical Journal. 149 (3): 11. Bibcode:2015AJ....149..113B. doi:10.1088/0004-6256/149/3/113 . Retrieved 11 July 2017.
      11. 1 2 3 4 Grav, T.; Mainzer, A. K.; Bauer, J. M.; Masiero, J. R.; Nugent, C. R. (November 2012). "WISE/NEOWISE Observations of the Jovian Trojan Population: Taxonomy". The Astrophysical Journal. 759 (1): 10. arXiv: 1209.1549 . Bibcode:2012ApJ...759...49G. doi:10.1088/0004-637X/759/1/49. S2CID   119101711. (online catalog)
      12. 1 2 3 Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi: 10.1093/pasj/63.5.1117 . (online, AcuA catalog p. 153)
      13. 1 2 3 4 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T . Retrieved 13 June 2018.
      14. 1 2 3 Carry, B. (December 2012). "Density of asteroids". Planetary and Space Science. 73 (1): 98–118. arXiv: 1203.4336 . Bibcode:2012P&SS...73...98C. doi:10.1016/j.pss.2012.03.009. S2CID   119226456. See Table 1.
      15. Gonano, M.; Mottola, S.; Neukum, G.; di Martino, M. (December 1990). "Physical study of outer belt asteroids". Space Dust and Debris; Proceedings of the Topical Meeting of the Interdisciplinary Scientific Commission B /Meetings B2. 11 (12): 197–200. Bibcode:1991AdSpR..11..197G. doi:10.1016/0273-1177(91)90563-Y. ISSN   0273-1177 . Retrieved 11 July 2017.
      16. 1 2 Marchis, Franck; Hestroffer, Daniel; Descamps, Pascal; Berthier, Jérô; me; Bouchez, Antonin H.; et al. (February 2006). "A low density of 0.8gcm-3 for the Trojan binary asteroid 617Patroclus". Nature. 439 (7076): 565–567. arXiv: astro-ph/0602033 . Bibcode:2006Natur.439..565M. doi:10.1038/nature04350. PMID   16452974. S2CID   4416425 . Retrieved 11 July 2017.
      17. 1 2 Behrend, Raoul. "Asteroids and comets rotation curves – (617) Patroclus". Geneva Observatory. Retrieved 11 July 2017.
      18. 1 2 Mueller, Michael; Marchis, Franck; Emery, Joshua P.; Harris, Alan W.; Mottola, Stefano; Hestroffer, Daniel; et al. (February 2010). "Eclipsing binary Trojan asteroid Patroclus: Thermal inertia from Spitzer observations". Icarus. 205 (2): 505–515. arXiv: 0908.4198 . Bibcode:2010Icar..205..505M. doi:10.1016/j.icarus.2009.07.043. S2CID   118634843.
      19. 1 2 3 Oey, Julian (July 2012). "Period Determination of 617 Patroclus". The Minor Planet Bulletin. 39 (3): 106–107. Bibcode:2012MPBu...39..106O. ISSN   1052-8091 . Retrieved 11 July 2017.
      20. 1 2 3 4 "Asteroid 617 Patroclus". Small Bodies Data Ferret. Retrieved 13 June 2018.
      21. 1 2 3 Chatelain, Joseph P.; Henry, Todd J.; French, Linda M.; Winters, Jennifer G.; Trilling, David E. (June 2016). "Photometric colors of the brightest members of the Jupiter L5 Trojan cloud". Icarus. 271: 158–169. Bibcode:2016Icar..271..158C. doi: 10.1016/j.icarus.2016.01.026 . Retrieved 12 June 2018.
      22. Redfield (1994) Nature and culture in the Iliad: the tragedy of Hector
      23. Merline, W. J. (2001), IAUC 7741: 2001fc; S/2001 (617) 1; C/2001 T1, C/2001 T2
      24. "Satellites and Companions of Minor Planets". IAU / CBAT. 17 September 2009. Archived from the original on 21 January 2011. Retrieved 25 January 2011.
      25. 1 2 3 Marchis, F.; Hestroffer, D.; Descamps, P.; Berthier, J. R. M.; Bouchez, A. H.; Campbell, R. D.; Chin, J. C. Y.; Van Dam, M. A.; Hartman, S. K.; Johansson, E. M.; Lafon, R. E.; Le Mignant, D. L.; De Pater, I.; Stomski, P. J.; Summers, D. M.; Vachier, F. D. R.; Wizinovich, P. L.; Wong, M. H. (2 February 2006). "A low density of 0.8 g cm-3 for the Trojan binary asteroid 617 Patroclus". Nature. 439 (7076): 565–567. arXiv: astro-ph/0602033 . Bibcode:2006Natur.439..565M. doi:10.1038/nature04350. PMID   16452974. S2CID   4416425.
      26. Sanders, Robert (2006), Binary asteroid in Jupiter's orbit may be icy comet from solar system's infancy, University of California, Berkeley
      27. Sanders, Robert. "Trojan Binary Asteroid – Patroclus & Menoetius". UC Berkeley. Retrieved 4 October 2017.
      28. Morbidelli, A.; Levison, H. F.; Tsiganis, K.; Gomes, R. (26 May 2005). "Chaotic capture of Jupiter's Trojan asteroids in the early Solar System". Nature. 435 (7041): 462–465. Bibcode:2005Natur.435..462M. doi:10.1038/nature03540. PMID   15917801. S2CID   4373366.
      29. Dreier, Casey; Lakdawalla, Emily (30 September 2015). "NASA announces five Discovery proposals selected for further study". The Planetary Society. Retrieved 1 October 2015.
      30. This poetic exception to normal Latin stress assignment is allowed when the final syllable starts with a sequence of two consonants, the first a b c d g p t (a plosive) and the second an l or r (a liquid). It is used for metrical convenience in Latin, and Pope retained it in his English translation.