+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   2207 Antenor (1977 QH1) Classification: Jupiter Trojan          SPK-ID: 2002207 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 38 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .01480562599848128 4.037e-08   a 5.156548305525552 6.07e-08 au q 5.080202379870839 1.884e-07 au i 6.800563389703867 3.9052e-06 deg node 159.0693618582734 3.3361e-05 deg peri 310.1244913536085 0.00014599 deg M 135.7396030746766 0.00014164 deg tp 2457387.846227952426 (2015-Dec-31.34622795) 0.0016803 TDB period 4276.978455710794 11.71 7.552e-05 2.068e-07 d yr n .08417157199361466 1.4862e-09 deg/d Q 5.232894231180266 6.1599e-08 au   Orbit Determination Parameters    # obs. used (total)      3098      data-arc span      22378 days (61.27 yr)      first obs. used      1959-03-11      last obs. used      2020-06-16      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .44227      source      ORB      producer      Otto Matic      solution date      2020-Jun-23 15:42:03   Additional Information  Earth MOID = 4.10093 au   Jupiter MOID = .219454 au   T_jup = 2.986  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 8.9   n/a MPO492776 IRAS observations used: 9 diameter diameter 97.658 km 0.504 urn:nasa:pds:neowise_diameters_albedos::2.0[jupiter_trojans] (http://adsabs.harvard.edu/abs/2012ApJ...759...49G)   rotation period rot_per 7.9647 h n/a LCDB (Rev. 2019-August); Warner et al., 2009 Published Reference List: [Gonano, M.; Di Martino, M.; Mottola, S.; Neukum, G. (1991) Adv. Space Res. 11, no. 12, 197-200.] [Mottola, S.; Di Martino, M.; Erikson, A.; Gonano-Beurer, M.; et al. (2011) Astron. J. 141, A170.] [Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.] [Stephens, R.D.; Coley, D.R.; French, L.M. (2016) Minor Planet Bull. 43, 265-270.] [Stephens, R.D.; Coley, D.R. (2017) Minor Planet Bull. 44, 252-257.] [Stephens, R.D.; Pravec, P.; Kueakova, H.; Kusnirak, P.; et al. (2018) Minor Planet Bull. 45, 341-342.] [Stephens, R. D.; Warner, B. D. (2019) MPB 46, 315-317.] geometric albedo albedo 0.051   0.003 urn:nasa:pds:neowise_diameters_albedos::2.0[jupiter_trojans] (http://adsabs.harvard.edu/abs/2012ApJ...759...49G)   B-V BV 0.733   0.035 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=3; phase (min.=1.44, mean=2.56, max.=4.58) deg. U-B UB 0.232   0.038 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=3; phase (min.=1.44, mean=2.56, max.=4.58) deg. Tholen spectral type spec_T D   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo 2207 Antenor           Discovered 1977 Aug. 19 by N. S. Chernykh at the Crimean Astrophysical Observatory. This Trojan planet is named for the Trojan hero and sage who called for peace with the Greeks. He advised the citizens of Troy to put an end to the war by returning the kidnapped Helen to her husband Menelaus. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: MPC 5849 Last Updated: 2006-03-21 Alternate Designations  1977 QH1 = 1959 EM = 1971 BE1 = 1978 UU  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2020-Jul-04 22:16 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin