+ 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 2459200.5 (2020-Dec-17.0) TDB Reference: JPL 40 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1108940049419892 3.0657e-08   a 3.035476265779061 1.324e-08 au q 2.698860145760468 9.4952e-08 au i 11.44963220348151 3.1592e-06 deg node 135.9003241926053 1.7257e-05 deg peri 262.9494274790533 2.3268e-05 deg M 357.1006919852336 1.4335e-05 deg tp 2459216.057168100800 (2021-Jan-01.55716810) 7.6902e-05 TDB period 1931.695593487807 5.29 1.2639e-05 3.46e-08 d yr n .1863647674165864 1.2193e-09 deg/d Q 3.372092385797656 1.4709e-08 au   Orbit Determination Parameters    # obs. used (total)      2880      data-arc span      30282 days (82.91 yr)      first obs. used      1938-02-19      last obs. used      2021-01-16      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .43114      source      ORB      producer      Otto Matic      solution date      2021-Feb-24 01:04:54   Additional Information  Earth MOID = 1.73508 au   Jupiter MOID = 2.08096 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 11.40   n/a E2021B10   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 ] 2021-Feb-28 07:32 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin