+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   21645 Chentsaiwei (1999 NZ50) Classification: Main-belt Asteroid          SPK-ID: 2021645 [ 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 21 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2142466642484322 6.2248e-08   a 2.546226860013496 1.4239e-08 au q 2.000706248835844 1.5475e-07 au i 11.5968918515384 7.4033e-06 deg node 289.8630661876877 3.1021e-05 deg peri 62.28361448061408 3.7716e-05 deg M 62.5412303385969 2.3115e-05 deg tp 2458942.685114012276 (2020-Apr-03.18511401) 9.483e-05 TDB period 1484.03474720742 4.06 1.2449e-05 3.408e-08 d yr n .2425819211291579 2.0349e-09 deg/d Q 3.091747471191147 1.729e-08 au   Orbit Determination Parameters    # obs. used (total)      943      data-arc span      10802 days (29.57 yr)      first obs. used      1991-07-18      last obs. used      2021-02-12      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .44351      source      ORB      producer      Otto Matic      solution date      2021-Apr-13 03:51:04   Additional Information  Earth MOID = 1.0218 au   Jupiter MOID = 2.42386 au   T_jup = 3.382  [ 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 14.32   n/a E2021B10   diameter diameter 4.013 km 0.726 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.275   0.071 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   21645 Chentsaiwei           Discovered 1999 July 14 by the Lincoln Laboratory Near-Earth Asteroid Research Team at Socorro. Chen Tsai Wei (b. 1989) was awarded first place and Best in Category in the 2006 Intel International Science and Engineering Fair for her chemistry project. She attends the Affiliated Senior High School of NKNU, Kaohsiung, Taiwan, Chinese Taipei. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: 20060711/MPCPages.arc Last Updated: 2006-07-17 [ show close-approach data ] Alternate Designations  1999 NZ50 = 1991 OA2  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-22 12:37 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin