+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   684 Hildburg (A909 PB) Classification: Main-belt Asteroid          SPK-ID: 2000684 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 45 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .03518206871476867 3.3377e-08   a 2.431681764319193 6.9721e-09 au q 2.346130169394465 8.0944e-08 au i 5.52241678032498 4.3357e-06 deg node 336.3587872626605 3.787e-05 deg peri 290.4443189786259 7.3894e-05 deg M 122.8022235289966 6.3584e-05 deg tp 2458528.043026630651 (2019-Feb-13.54302663) 0.00024449 TDB period 1385.027937810951 3.79 5.9567e-06 1.631e-08 d yr n .2599225547529267 1.1179e-09 deg/d Q 2.51723335924392 7.2174e-09 au   Orbit Determination Parameters    # obs. used (total)      2992      data-arc span      40626 days (111.23 yr)      first obs. used      1909-08-19      last obs. used      2020-11-10      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .41734      source      ORB      producer      Otto Matic      solution date      2020-Dec-18 01:55:21   Additional Information  Earth MOID = 1.33694 au   Jupiter MOID = 2.51163 au   T_jup = 3.500  [ show covariance matrix ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] Physical Parameter Table Parameter Symbol Value Units Sigma Reference Notes absolute magnitude H 10.8   n/a MPO448917   diameter diameter 19.040 km 0.188 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 15.89 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Result based on less than full coverage, so that the period may be wrong by 30 percent or so. Published Reference List: [Ferrero, A. (2014) Minor Planet Bull. 41, 184-185.] geometric albedo albedo 0.238   0.043 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   B-V BV 0.960   0.020 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=13.18 deg. U-B UB 0.500   0.030 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=13.18 deg. 684 Hildburg (A909 PB)          Discovered 1909-Aug-08 by Kopff, A. at Heidelberg Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  A909 PB = 1928 PB = 1938 CT  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jan-28 04:28 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin