5244 Amphilochos

5244 Amphilochos /æmˈfɪləkəs/ is a mid-sized Jupiter trojan from the Greek camp, approximately 36 kilometers (22 miles) in diameter. It was discovered at the Palomar Observatory during the second Palomar–Leiden Trojan survey in 1973, and was later named after the seer Amphilochus from Greek mythology.[1] The dark Jovian asteroid is likely elongated in shape and has a rotation period of 7.8 hours.[8]

5244 Amphilochos
Discovery[1]
Discovered byC. J. van Houten
I. van Houten-G.
T. Gehrels
Discovery sitePalomar Obs.
Discovery date29 September 1973
Designations
(5244) Amphilochos
Pronunciation/æmˈfɪləkəs/[2]
Named after
Amphilochus[1]
(Greek mythology)
1973 SQ1 · 1989 AO2
Jupiter trojan[1][3]
Greek[4] · background[5]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc62.52 yr (22,836 d)
Aphelion5.3177 AU
Perihelion5.0270 AU
5.1723 AU
Eccentricity0.0281
11.76 yr (4,297 d)
318.67°
0° 5m 1.68s / day
Inclination6.1555°
213.29°
125.05°
Jupiter MOID0.1211 AU
TJupiter2.9880
Physical characteristics
Mean diameter
36.69±0.69 km[6]
9.766±0.002 h[7][lower-alpha 1]
0.091±0.018[6]
C(assumed)[8]
V–R = 0.407±0.044[9]
V–I = 0.770±0.047[9]
10.40[1][3]
10.509±0.007 (R)[10]
10.96[8]

    Discovery

    Amphilochos was discovered on 29 September 1973, by Dutch astronomer couple Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by astronomer Tom Gehrels at the Palomar Observatory in California.[1] The body's observation arc begins with a precovery taken at Palomar in April 1955, more than 18 years prior to its official discovery observation.[1]

    Palomar–Leiden Trojan survey

    Despite being discovered during the second Palomar–Leiden Trojan survey in 1973, Amphilochos has not received a provisional survey designation prefixed with "T-2". The survey was a fruitful collaboration between the Palomar and Leiden observatories during the 1960s and 1970s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory where astrometry was carried out. The trio are credited with the discovery of several thousand asteroids.[11]

    Orbit and classification

    Amphilochos is a dark Jovian asteroid in a 1:1 orbital resonance with Jupiter. It is located in the leading Greek camp at the Gas Giant's L4 Lagrangian point, 60° ahead on its orbit (see Trojans in astronomy).[4] It is also a non-family asteroid of the Jovian background population.[5][12]

    It orbits the Sun at a distance of 5.0–5.3 AU once every 11 years and 9 months (4,297 days; semi-major axis of 5.17 AU). Its orbit has an eccentricity of 0.03 and an inclination of 6° with respect to the ecliptic.[3]

    Naming

    This minor planet was named from Greek mythology after the seer Amphilochus, son of Amphiaraus. After the Trojan War, he was warned by a vision which saved his life as he returned to the Trojan shore before the Greek fleet departed. Amphilochus lived together with Calchas (see 4138 Kalchas) in Asia Minor. The official naming citation was published by the Minor Planet Center on 26 February 1994 (M.P.C. 23137).[13]

    Physical characteristics

    Amphilochos is an assumed C-type asteroid, while the majority of larger Jupiter trojans are D-types.[8] It has an untypically low V–I color index of 0.77 (see table below).[9]

    Rotation period

    In September 2010, a first rotational lightcurve of Amphilochos was obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory. Lightcurve analysis gave a rotation period of 9.787 hours with a brightness variation of 0.51 magnitude (U=2).[10] The best-rated lightcurve with a well-defined period of 9.766±0.002 hours and a high amplitude of 0.79 magnitude was obtained by Robert Stephens at the Center for Solar System Studies in Landers, California, in May 2015. A high brightness amplitude typically indicates that the body has a non-spherical shape.[7][lower-alpha 1]

    In August 2015, observations by the Kepler space telescope during its K2 mission gave another two lightcurves with a concurring period of 9.578 and 9.797 hours with a brightness variation of 0.73 and 0.67 magnitude, respectively (U=2/2+).[14][15] The Collaborative Asteroid Lightcurve Link (CALL), labels the period determination for this asteroid as ambiguous.[8]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Amphilochos measures 36.69 kilometers in diameter and its surface has an albedo of 0.091,[6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a carbonaceous asteroid of 0.057 and calculates a diameter of 35.79 kilometers based on an absolute magnitude of 10.96.[8]

    100+ largest Jupiter trojans
    Largest Jupiter Trojans by survey(A)
    (mean-diameter in kilometers; YoD: Year of Discovery)
    Designation H WISE IRAS Akari Ln RP V–I YoD Ref
    624 Hektor7.2225233230.99L46.920.9301907list
    617 Patroclus8.19140.362140.92140.85L5102.800.8301906list
    911 Agamemnon7.89131.038166.66185.30L46.590.9801919list
    588 Achilles8.67130.099135.47133.22L47.310.9401906list
    3451 Mentor8.4126.288116.30117.91L57.700.7701984list
    3317 Paris8.3118.790116.26120.45L57.090.9501984list
    1867 Deiphobus8.3118.220122.67131.31L558.660.9301971list
    1172 Äneas8.33118.020142.82148.66L58.710.9501930list
    1437 Diomedes8.3117.786164.31172.60L424.490.8101937list
    1143 Odysseus7.93114.624125.64130.81L410.110.8601930list
    2241 Alcathous8.64113.682114.63118.87L57.690.9401979list
    659 Nestor8.99112.320108.87107.06L415.980.7901908list
    3793 Leonteus8.7112.04686.2687.58L45.620.7801985list
    3063 Makhaon8.4111.655116.14114.34L48.640.8301983list
    1583 Antilochus8.6108.842101.62111.69L431.540.9501950list
    884 Priamus8.81101.09396.29119.99L56.860.9001917list
    1208 Troilus8.99100.477103.34111.36L556.170.7401931list
    1173 Anchises8.8999.549126.27120.49L511.600.7801930list
    2207 Antenor8.8997.65885.1191.32L57.970.9501977list
    2363 Cebriones9.1195.97681.8484.61L520.050.9101977list
    4063 Euforbo8.795.619102.46106.38L48.850.9501989list
    2357 Phereclos8.9494.62594.9098.45L514.390.9601981list
    4709 Ennomos8.591.43380.8580.03L512.280.6901988list
    2797 Teucer8.789.430111.14113.99L410.150.9201981list
    2920 Automedon8.888.574111.01113.11L410.210.9501981list
    (15436) 1998 VU309.187.64685.7178.63L48.970.8701998list
    3596 Meriones9.287.38075.0973.28L412.960.8301985list
    2893 Peiroos9.2386.88487.4686.76L58.960.9501975list
    4086 Podalirius9.185.49586.8985.98L410.430.8701985list
    4060 Deipylos9.384.04379.2186.79L49.300.7601987list
    1404 Ajax9.383.99081.6996.34L429.380.9601936list
    4348 Poulydamas9.582.03270.0887.51L59.910.8401988list
    5144 Achates9.080.95891.9189.85L55.960.9201991list
    4833 Meges8.980.16587.3389.39L414.250.9401989list
    2223 Sarpedon9.4177.48094.63108.21L522.740.8801977list
    (4489) 1988 AK9.076.59592.9395.02L412.580.9501988list
    2260 Neoptolemus9.3176.43571.6581.28L48.180.9501975list
    5254 Ulysses9.276.14778.3480.00L428.720.9701986list
    (3708) 1974 FV19.375.66179.5976.75L56.550.9801974list
    2674 Pandarus9.174.26798.10101.72L58.481.0001982list
    3564 Talthybius9.473.73068.9274.11L440.590.9001985list
    4834 Thoas9.172.33186.8296.21L418.190.9501989list
    (7641) 1986 TT69.471.83968.9775.28L427.770.9801986list
    3540 Protesilaos9.370.22576.8487.66L48.950.9401973list
    (11395) 1998 XN779.868.97764.7167.78L417.381998list
    (4035) 1986 WD9.668.73368.2366.99L413.470.9701986list
    5264 Telephus9.468.47273.2681.38L49.530.9701991list
    1868 Thersites9.568.16370.0878.89L410.480.9601960list
    (9799) 1996 RJ9.668.03364.8772.42L421.520.9101996list
    4068 Menestheus9.567.62562.3768.46L414.400.9501973list
    (23135) 2000 AN1469.966.23058.2968.50L48.690.8602000list
    2456 Palamedes9.365.91691.6699.60L47.240.9201966list
    3709 Polypoites9.165.29799.0985.23L410.041.0001985list
    1749 Telamon9.564.89881.0669.14L416.980.9701949list
    3548 Eurybates9.663.88572.1468.40L48.710.7301973list
    4543 Phoinix9.763.83662.7969.54L438.871.2001989list
    12444 Prothoon9.863.83564.3162.41L515.821996list
    4836 Medon9.563.27767.7378.70L49.820.9201989list
    (16070) 1999 RB1019.763.19164.1368.98L520.240.9601999list
    (15440) 1998 WX49.662.51966.4871.88L421.430.9701998list
    (4715) 1989 TS19.762.09763.9165.93L58.810.8501989list
    (34746) 2001 QE919.861.68460.5163.63L519.630.9502001list
    (38050) 1998 VR389.861.60361.0450.44L418.850.9901998list
    5130 Ilioneus9.760.71159.4052.49L514.770.9601989list
    5027 Androgeos9.659.78657.86n.a.L411.380.9101988list
    (6090) 1989 DJ9.459.56874.5381.92L418.480.9801989list
    (5648) 1990 VU19.759.29563.91n.a.L537.560.9001990list
    7119 Hiera9.759.15076.4077.29L44000.9501989list
    4805 Asteropaios10.057.64753.1643.44L512.371990list
    16974 Iphthime9.857.34155.4357.15L478.90.9601998list
    4867 Polites9.857.25158.2964.29L511.241.0101989list
    2895 Memnon10.056.70655.67n.a.L57.500.7101981list
    4708 Polydoros9.954.96455.67n.a.L57.520.9601988list
    (21601) 1998 XO8910.054.90955.6756.08L412.650.9701998list
    (12929) 1999 TZ19.954.07761.0455.34L59.270.8801999list
    17492 Hippasos10.053.97555.67n.a.L517.751991list
    5652 Amphimachus10.153.92153.1652.48L48.371.0501992list
    2759 Idomeneus9.953.67661.0152.55L432.380.9101980list
    (5258) 1989 AU110.253.27550.77n.a.L419.851.0101989list
    (12126) 1999 RM1110.153.202n.a.n.a.L5n.a.?1999list
    (15502) 1999 NV2710.053.10055.6750.86L515.130.8751999list
    4754 Panthoos10.053.02553.1556.96L527.681977list
    4832 Palinurus10.052.05853.16n.a.L55.321.0001988list
    5126 Achaemenides10.551.92244.2248.57L453.021989list
    3240 Laocoon10.251.69550.77n.a.L511.310.8801978list
    4902 Thessandrus9.851.26361.0471.79L47380.9601989list
    11552 Boucolion10.151.13653.1653.91L532.441993list
    (20729) 1999 XS14310.450.96146.30n.a.L45.721.0001999list
    (6545) 1986 TR610.150.95153.16n.a.L416.260.9101986list
    4792 Lykaon10.150.87053.16n.a.L540.090.9601988list
    21900 Orus10.050.81055.6753.87L413.450.9501999list
    1873 Agenor10.150.79953.7654.38L520.601971list
    5028 Halaesus10.250.77050.77n.a.L424.940.9001988list
    2146 Stentor9.950.75558.29n.a.L416.401976list
    4722 Agelaos10.050.37853.1659.47L518.440.9101977list
    5284 Orsilocus10.150.15953.16n.a.L410.310.9701989list
    11509 Thersilochos10.149.96053.1656.23L517.371990list
    5285 Krethon10.149.60658.5352.61L412.041.0901989list
    4791 Iphidamas10.149.52857.8559.96L59.701.0301988list
    9023 Mnesthus10.149.15150.7760.80L530.661988list
    5283 Pyrrhus9.748.35664.5869.93L47.320.9501989list
    4946 Askalaphus10.248.20952.7166.10L422.730.9401988list
    (22149) 2000 WD4910.248.19050.7750.37L47.841.0902000list
    (32496) 2000 WX18210.248.01750.7751.63L523.340.9502000list
    5120 Bitias10.247.98750.77n.a.L515.210.7801988list
    12714 Alkimos10.147.81961.0454.62L428.481991list
    (7352) 1994 CO9.947.73155.67 47.07L56480.8501994list
    1870 Glaukos10.647.64942.23n.a.L55.991971list
    4138 Kalchas10.146.46253.1661.04L429.20.8101973list
    (23958) 1998 VD3010.246.00150.7747.91L45620.9901998list
    4828 Misenus10.445.95446.30 43.22L512.870.9201988list
    4057 Demophon10.145.68353.16n.a.L429.821.0601985list
    4501 Eurypylos10.445.52446.30n.a.L46.051989list
    4007 Euryalos10.345.51548.4853.89L46.391973list
    5259 Epeigeus10.344.74142.5944.42L418.421989list
    30705 Idaios10.444.54646.30n.a.L515.741977list
    16560 Daitor10.743.86151.4243.38L51991list
    (15977) 1998 MA1110.443.53046.3051.53L52500.9061998list
    7543 Prylis10.642.89342.23n.a.L417.801973list
    4827 Dares10.542.77044.22n.a.L519.001988list
    1647 Menelaus10.542.71644.22n.a.L417.740.8661957list
    (A) Used sources: WISE/NEOWISE catalog (NEOWISE_DIAM_V1 PDS, Grav, 2012); IRAS data (SIMPS v.6 catalog); and Akari catalog (Usui, 2011); RP: rotation period and V–I (color index) taken from the LCDB

    Note: missing data was completed with figures from the JPL SBDB (query) and from the LCDB (query form) for the WISE/NEOWISE and SIMPS catalogs, respectively. These figures are given in italics. Also, listing is incomplete above #100.

    Notes

    1. Lightcurve plots of (5244) Amphilochos from May 2015 by Robert Stephens at the Center for Solar System Studies (U81). Quality code is 3 (lightcurve rating at CS3). Summary figures at the LCDB and CS3.

    References

    1. "5244 Amphilochos (1973 SQ1)". Minor Planet Center. Retrieved 2 July 2018.
    2. 'Amphilochus' in Noah Webster (1884) A Practical Dictionary of the English Language
    3. "JPL Small-Body Database Browser: 5244 Amphilochos (1973 SQ1)" (2017-10-27 last obs.). Jet Propulsion Laboratory. Retrieved 2 July 2018.
    4. "List of Jupiter Trojans". Minor Planet Center. 1 July 2018. Retrieved 2 July 2018.
    5. "Asteroid (5244) Amphilochos – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 2 July 2018.
    6. 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. (online catalog)
    7. Stephens, Robert D.; Coley, Daniel, R.; French, Linda M. (January 2016). "Large L5 Jovian Trojan Asteroid Lightcurves from the Center for Solar System Studies". The Minor Planet Bulletin. 43 (1): 15–22. Bibcode:2016MPBu...43...15S. ISSN 1052-8091.
    8. "LCDB Data for (5244) Amphilochos". Asteroid Lightcurve Database (LCDB). Retrieved 2 July 2018.
    9. Hainaut, O. R.; Boehnhardt, H.; Protopapa, S. (October 2012). "Colours of minor bodies in the outer solar system. II. A statistical analysis revisited". Astronomy and Astrophysics. 546: 20. arXiv:1209.1896. Bibcode:2012A&A...546A.115H. doi:10.1051/0004-6361/201219566.
    10. Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv:1504.04041. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75.
    11. "Minor Planet Discoverers". Minor Planet Center. 31 May 2018. Retrieved 21 June 2018.
    12. "Asteroid 5244 Amphilochos". Small Bodies Data Ferret. Retrieved 2 July 2018.
    13. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 2 July 2018.
    14. Szabó, Gy. M.; Pál, A.; Kiss, Cs.; Kiss, L. L.; Molnár, L.; Hanyecz, O.; et al. (March 2017). "The heart of the swarm: K2 photometry and rotational characteristics of 56 Jovian Trojan asteroids". Astronomy and Astrophysics. 599: 13. arXiv:1609.02760. Bibcode:2017A&A...599A..44S. doi:10.1051/0004-6361/201629401.
    15. Ryan, Erin Lee; Sharkey, Benjamin N. L.; Woodward, Charles E. (March 2017). "Trojan Asteroids in the Kepler Campaign 6 Field". The Astronomical Journal. 153 (3): 12. Bibcode:2017AJ....153..116R. doi:10.3847/1538-3881/153/3/116.

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