+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   869 Mellena (A917 JB) Classification: Main-belt Asteroid          SPK-ID: 2000869 [ 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 45 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2200287169615246 1.6673e-08   a 2.689083401536897 7.7137e-09 au q 2.097407830894201 4.4135e-08 au i 7.838266674244524 7.6225e-07 deg node 154.8761966286576 6.4871e-06 deg peri 107.1218637118962 7.6063e-06 deg M 135.0646535457779 5.3598e-06 deg tp 2458596.211898484028 (2019-Apr-22.71189848) 2.2785e-05 TDB period 1610.663566186226 4.41 6.9303e-06 1.897e-08 d yr n .2235103640249453 9.6172e-10 deg/d Q 3.280758972179593 9.4109e-09 au   Orbit Determination Parameters    # obs. used (total)      3140      data-arc span      37918 days (103.81 yr)      first obs. used      1917-05-10      last obs. used      2021-03-03      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .40943      source      ORB      producer      Otto Matic      solution date      2021-Mar-16 11:50:31   Additional Information  Earth MOID = 1.09652 au   Jupiter MOID = 1.86792 au   T_jup = 3.324  [ 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 11.96   n/a E2021B10   diameter diameter 21.193 km 0.090 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 6.5155 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Stephens, R.D. (2010) Minor Planet Bull. 37, 159-161.] [Carbognani, A. (2011) Minor Planet Bull. 38, 57-63.] [Ferrero, A. (2011) Entry on CALL web site. http://www.minorplanet.info/call.html] [Owings, L.E. (2011) Minor Planet Bull. 38, 9-10.] [Franco, L.; Marchini, A.; Arena, C.; Casalnuovo, G.B.; et al. (2020) Minor Planet Bull. 47, 61-63.] geometric albedo albedo 0.065   0.009 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   869 Mellena (A917 JB)          Discovered 1917-May-09 by Schorr, R. at Bergedorf Independent discovery May 10 by M. Wolf, Heidelberg, was announced first. Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  A917 JB = 1931 RC = 1944 OB = 1952 DL2  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Apr-11 17:12 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin