+ 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 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 20 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1445125676272651 4.6041e-08   a 3.096481044681394 2.8939e-08 au q 2.64900061830533 1.5216e-07 au i 14.42525476312607 5.2114e-06 deg node 264.2950605760676 2.4357e-05 deg peri 5.345229966711105 3.4369e-05 deg M 8.478496257577014 2.4252e-05 deg tp 2459153.627577724416 (2020-Oct-31.12757772) 0.00013415 TDB period 1990.219905343494 5.45 2.79e-05 7.639e-08 d yr n .1808845339318759 2.5358e-09 deg/d Q 3.543961471057459 3.3121e-08 au   Orbit Determination Parameters    # obs. used (total)      765      data-arc span      7682 days (21.03 yr)      first obs. used      1999-07-12      last obs. used      2020-07-23      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .53428      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 15:39:13   Additional Information  Earth MOID = 1.63152 au   Jupiter MOID = 1.56583 au   T_jup = 3.159  [ 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 14.09   n/a E2021B55   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 ] 2021-Apr-20 03:35 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin