+ 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 35 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1108338279590662 3.1183e-08   a 3.035463439499086 1.6368e-08 au q 2.699031406869609 9.5221e-08 au i 11.4495562024871 3.9307e-06 deg node 135.8997947443969 1.7856e-05 deg peri 262.8814520090768 2.517e-05 deg M 319.8805289066348 1.8452e-05 deg tp 2459215.772539788567 (2021-Jan-01.27253979) 9.9432e-05 TDB period 1931.683350050452 5.29 1.5624e-05 4.278e-08 d yr n .1863659486378021 1.5074e-09 deg/d Q 3.371895472128563 1.8182e-08 au   Orbit Determination Parameters    # obs. used (total)      2327      data-arc span      30056 days (82.29 yr)      first obs. used      1938-02-19      last obs. used      2020-06-04      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .47437      source      ORB      producer      Otto Matic      solution date      2020-Jun-23 15:48:45   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-Jul-11 02:39 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin