+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   49212 (1998 SM121) Classification: Main-belt Asteroid          SPK-ID: 2049212 [ 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 29 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .05704490149437007 4.2719e-08   a 2.294297664752694 8.6892e-09 au q 2.163419680468114 1.0095e-07 au i 3.974876270024793 3.633e-06 deg node 258.3110909154371 5.9224e-05 deg peri 239.9422184491025 6.9599e-05 deg M 330.4845885047965 3.6228e-05 deg tp 2459104.568528336356 (2020-Sep-12.06852834) 0.00012775 TDB period 1269.325694719739 3.48 7.211e-06 1.974e-08 d yr n .2836151521217619 1.6112e-09 deg/d Q 2.425175649037275 9.1849e-09 au   Orbit Determination Parameters    # obs. used (total)      1361      data-arc span      8083 days (22.13 yr)      first obs. used      1998-09-26      last obs. used      2020-11-12      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .52468      source      ORB      producer      Otto Matic      solution date      2020-Dec-17 21:27:39   Additional Information  Earth MOID = 1.18014 au   Jupiter MOID = 2.58748 au   T_jup = 3.591  [ 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 15.0   n/a MPO502483   diameter diameter 2.339 km 0.279 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   geometric albedo albedo 0.388   0.102 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2011ApJ...741...68M)   49212 (1998 SM121)          Discovered 1998-Sep-26 by LINEAR at Socorro Reference: 20021120/Numbers.arc Last Updated: 2004-04-19 [ show close-approach data ] Alternate Designations  1998 SM121 = 2000 EY91  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-25 09:06 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin