+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   1446 Sillanpaa (1938 BA) Classification: Main-belt Asteroid          SPK-ID: 2001446 [ 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 33 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1018742027691878 3.1727e-08   a 2.245871918946678 5.0062e-09 au q 2.01707550768228 7.0346e-08 au i 5.255705503689589 3.7259e-06 deg node 17.50227871009067 3.2059e-05 deg peri 196.4753327995691 3.6181e-05 deg M 89.32256853103 1.6924e-05 deg tp 2458695.475582356560 (2019-Jul-30.97558236) 5.7638e-05 TDB period 1229.351015734524 3.37 4.1104e-06 1.125e-08 d yr n .2928374364948191 9.7913e-10 deg/d Q 2.474668330211077 5.5162e-09 au   Orbit Determination Parameters    # obs. used (total)      3154      data-arc span      30239 days (82.79 yr)      first obs. used      1938-01-26      last obs. used      2020-11-10      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .40607      source      ORB      producer      Otto Matic      solution date      2020-Dec-18 02:00:37   Additional Information  Earth MOID = 1.01148 au   Jupiter MOID = 2.49101 au   T_jup = 3.618  [ 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 12.6   n/a MPO332828   diameter diameter 8.167 km 0.154 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 9.6602 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Galad, A. (2009) Minor Planet Bull. 36, 183-186.] [Pravec, P.; Wolf, M.; Sarounova, L. (2009) http://www.asu.cas.cz/~ppravec/neo.htm] [Hanus, J.; Broz, M.; Durech, J.; Warner, B.D.; et al. (2013) Astron. Astrophys. 559, A134.] [Waszczak, A.; Chang, C.-K.; Ofeck, E.O.; Laher, F.; et al. (2015) Astron. J. 150, A75.] geometric albedo albedo 0.241   0.046 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   1446 Sillanpaa (1938 BA)          Discovered 1938-Jan-26 by Vaisala, Y. at Turku Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  1938 BA = 1935 GB = 1952 HQ3 = 1955 DQ = 1965 EA  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-18 19:57 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin