+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   16991 (1999 CW4) Classification: Main-belt Asteroid          SPK-ID: 2016991 [ 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 34 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1573617940024685 3.3487e-08   a 2.420960755095322 7.4183e-09 au q 2.039994027463951 8.1417e-08 au i .6737606813180477 3.6787e-06 deg node 202.5748043870448 0.00026191 deg peri 329.4193388730764 0.00026212 deg M 281.566675321519 1.0418e-05 deg tp 2459500.263102308415 (2021-Oct-12.76310231) 4.0321e-05 TDB period 1375.878394463073 3.77 6.3239e-06 1.731e-08 d yr n .2616510306788323 1.2026e-09 deg/d Q 2.801927482726692 8.5856e-09 au   Orbit Determination Parameters    # obs. used (total)      1725      data-arc span      10029 days (27.46 yr)      first obs. used      1993-09-18      last obs. used      2021-03-04      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .50834      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 01:50:29   Additional Information  Earth MOID = 1.04514 au   Jupiter MOID = 2.16443 au   T_jup = 3.496  [ 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 14.7   n/a MPO435857   diameter diameter 2.816 km 0.143 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.322   0.087 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   16991 (1999 CW4)          Discovered 1999-Feb-12 by Korlevic, K. at Visnjan Reference: 20000913/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1999 CW4 = 1993 SQ9 = 1999 BL15  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-16 09:24 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin