+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   2690 Ristiina (1938 DG1) Classification: Main-belt Asteroid          SPK-ID: 2002690 [ 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 37 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1108338239170248 3.0874e-08   a 3.035463434163 1.5192e-08 au q 2.699031414394411 9.4887e-08 au i 11.44955502837353 3.7886e-06 deg node 135.8997987119899 1.7535e-05 deg peri 262.881443524234 2.437e-05 deg M 319.8805351616354 1.6949e-05 deg tp 2459215.772505657919 (2021-Jan-01.27250566) 9.1125e-05 TDB period 1931.68334495685 5.29 1.4501e-05 3.97e-08 d yr n .1863659491292253 1.3991e-09 deg/d Q 3.37189545393159 1.6875e-08 au   Orbit Determination Parameters    # obs. used (total)      2506      data-arc span      30165 days (82.59 yr)      first obs. used      1938-02-19      last obs. used      2020-09-21      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .45985      source      ORB      producer      Otto Matic      solution date      2020-Oct-22 15:41:03   Additional Information  Earth MOID = 1.73628 au   Jupiter MOID = 2.08139 au   T_jup = 3.202  [ 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 11.3   n/a MPO431526   diameter diameter 18.210 km 0.309 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   geometric albedo albedo 0.176   0.033 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   2690 Ristiina (1938 DG1)          Discovered 1938-Feb-24 by Vaisala, Y. at Turku Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1938 DG1 = 1935 QT = 1975 EM = 1977 PW = 1980 DK2 = 1980 EW  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2020-Oct-31 00:11 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin