+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   101891 (1999 NL55) Classification: Main-belt Asteroid          SPK-ID: 2101891 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 19 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1439780735346053 4.698e-08   a 3.09456031664539 2.9229e-08 au q 2.649011483818149 1.543e-07 au i 14.42874276152231 5.3971e-06 deg node 264.2954432903363 2.5083e-05 deg peri 5.385519596760587 3.5457e-05 deg M 332.2441000432606 2.4933e-05 deg tp 2459153.802651916340 (2020-Oct-31.30265192) 0.00013743 TDB period 1988.368410892825 5.44 2.8172e-05 7.713e-08 d yr n .1810529668585669 2.5652e-09 deg/d Q 3.540109149472632 3.3438e-08 au   Orbit Determination Parameters    # obs. used (total)      757      data-arc span      7682 days (21.03 yr)      first obs. used      1999-07-12      last obs. used      2020-07-23      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .53521      source      ORB      producer      Otto Matic      solution date      2020-Nov-12 19:57:57   Additional Information  Earth MOID = 1.63332 au   Jupiter MOID = 1.57052 au   T_jup = 3.160  [ 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 14.0   n/a MPO302565   diameter diameter 6.724 km 0.144 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.129   0.014 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   101891 (1999 NL55)          Discovered 1999-Jul-12 by LINEAR at Socorro Reference: 20051019/Numbers.arc Last Updated: 2005-10-26 [ show close-approach data ] Alternate Designations  1999 NL55 = 2000 WH4  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2020-Nov-28 10:53 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin