+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   3102 Krok (1981 QA) Classification: Amor [NEO]          SPK-ID: 2003102 [ 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 252 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .449371936215817 3.0413e-08   a 2.151223603815189 2.1818e-09 au q 1.18452408773559 6.489e-08 au i 8.442642744994522 3.4939e-06 deg node 172.0560833664416 2.2693e-05 deg peri 154.7610407932183 2.3504e-05 deg M 164.3355923884783 6.1357e-06 deg tp 2458674.415032366713 (2019-Jul-09.91503237) 1.9092e-05 TDB period 1152.462382587678 3.16 1.7532e-06 4.8e-09 d yr n .3123746210194513 4.7521e-10 deg/d Q 3.117923119894788 3.1622e-09 au   Orbit Determination Parameters    # obs. used (total)      1369      data-arc span      14451 days (39.56 yr)      first obs. used      1981-08-21      last obs. used      2021-03-15      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .49037      source      ORB      producer      Otto Matic      solution date      2021-Apr-18 06:24:48   Additional Information  Earth MOID = .182488 au   Jupiter MOID = 2.27883 au   T_jup = 3.555  [ 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 16.15   n/a E2020-QM5   diameter diameter 1.6 km n/a Hazards due to Comets and Asteroids (1994), Ed. T. Gehrels, pp.540-543 based on assumed medium albedo (0.15) rotation period rot_per 149.4 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Harris, A.W.; Young, J.W.; Dockweiler, T.; Gibson, J.; et al. (1992) Icarus 95, 115-147.] [Pravec, P.; et al. (2005) Icarus 173, 108-131.] B-V BV 0.834   0.021 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=2; phase (min.=24.29, mean=24.39, max.=24.49) deg. U-B UB 0.521   0.056 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=2; phase (min.=24.29, mean=24.39, max.=24.49) deg. Tholen spectral type spec_T QRS   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices SMASSII spectral type spec_B S   n/a Binzel et al. (2004) Icarus 170, 259-294   3102 Krok (1981 QA)          Discovered 1981-Aug-21 by Brozek, L. at Klet 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-22 15:53 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin