+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   4341 Poseidon (1987 KF) Classification: Apollo [NEO]          SPK-ID: 2004341 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 116 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .6798486775595314 4.5174e-08   a 1.835801316144916 5.765e-09 au q .5877342191017476 8.4087e-08 au i 11.84679077907927 6.0467e-06 deg node 108.0899629012707 2.204e-05 deg peri 15.738371631866 2.4033e-05 deg M 208.6473907764273 1.8376e-05 deg tp 2459582.465689564699 (2022-Jan-02.96568956) 4.7854e-05 TDB period 908.5251251940443 2.49 4.2796e-06 1.172e-08 d yr n .3962466089455816 1.8665e-09 deg/d Q 3.083868413188084 9.6844e-09 au   Orbit Determination Parameters    # obs. used (total)      530      data-arc span      12158 days (33.29 yr)      first obs. used      1987-05-29      last obs. used      2020-09-10      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .5563      source      ORB      producer      Otto Matic      solution date      2021-Apr-12 16:13:59   Additional Information  Earth MOID = .194202 au   Jupiter MOID = 2.02738 au   T_jup = 3.687  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 15.92   n/a E2020-QM5   diameter diameter 3.177 km 0.651 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2017AJ....154..168M)   rotation period rot_per 6.262 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Published Reference List: [Pravec, P.; Wolf, M.; Sarounova, L. (1998) Icarus 136, 124-153.] [Krugly, Yu.N.; Bel'skaya, I.N.; Shevchenko, V.G.; et al. (2002) Icarus 158, 294-304.] geometric albedo albedo 0.054   0.091 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2017AJ....154..168M)   SMASSII spectral type spec_B O   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002) 4341 Poseidon (1987 KF)          Discovered 1987-May-29 by Shoemaker, C. S. at Palomar Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-16 00:53 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin