+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   21155 (1993 NW1) Classification: Main-belt Asteroid          SPK-ID: 2021155 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459396.5 (2021-Jul-01.0) TDB Reference: JPL 36 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .03616473148524651 3.1563e-08   a 2.897672340864614 1.3426e-08 au q 2.79287879872502 9.2253e-08 au i 1.532903047112089 3.3311e-06 deg node 215.1265038934588 0.00013449 deg peri 75.20248191791316 0.00014359 deg M 244.0144518644224 5.1885e-05 deg tp 2459976.961899084001 (2023-Feb-01.46189908) 0.00026049 TDB period 1801.657939538949 4.93 1.2522e-05 3.428e-08 d yr n .1998159540162909 1.3887e-09 deg/d Q 3.002465883004209 1.3912e-08 au   Orbit Determination Parameters    # obs. used (total)      1887      data-arc span      10194 days (27.91 yr)      first obs. used      1993-07-12      last obs. used      2021-06-09      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .50964      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 05:06:09   Additional Information  Earth MOID = 1.77676 au   Jupiter MOID = 2.04881 au   T_jup = 3.287  [ 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 14.25   n/a MPCxxxxx   diameter diameter 3.910 km 0.838 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.290   0.175 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   21155 (1993 NW1)          Discovered 1993-Jul-12 by Elst, E. W. at La Silla Reference: 20010208/Numbers.arc Last Updated: 2004-04-19 Alternate Designations  1993 NW1 = 1999 VD55  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jul-30 18:37 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin