+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   917 Lyka (A915 RR) Classification: Main-belt Asteroid          SPK-ID: 2000917 [ 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 37 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .2006233193977694 3.4845e-08   a 2.38123685476962 6.2141e-09 au q 1.903505212693434 8.184e-08 au i 5.126366756543586 3.8235e-06 deg node 343.3840499306172 3.5107e-05 deg peri 359.8999348586725 3.5889e-05 deg M 181.9080817202567 7.9513e-06 deg tp 2459664.463233549513 (2022-Mar-25.96323355) 3.039e-05 TDB period 1342.153907862152 3.67 5.2537e-06 1.438e-08 d yr n .268225572261996 1.0499e-09 deg/d Q 2.858968496845805 7.4608e-09 au   Orbit Determination Parameters    # obs. used (total)      3146      data-arc span      36741 days (100.59 yr)      first obs. used      1919-12-01      last obs. used      2020-07-04      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .41023      source      ORB      producer      Otto Matic      solution date      2020-Nov-13 04:24:24   Additional Information  Earth MOID = .895689 au   Jupiter MOID = 2.54622 au   T_jup = 3.505  [ 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 11.6   n/a MPO358634   diameter diameter 34.878 km 0.184 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   rotation period rot_per 7.867 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Behrend, R. (2005) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Behrend, R. (2018) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] [Brincat, S.M.; Galdies, C.; Stone, G.; Grech, W. (2019) Minor Planet Bull. 46, 230-232.] [Carreno, A.; Arce, E.; Fornas, G.; Mas, V. (2019) Minor Planet Bull. 46, 200-203.] geometric albedo albedo 0.056   0.008 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M)   917 Lyka (A915 RR)          Discovered 1915-Sep-05 by Neujmin, G. at Simeis Discovered at Simeis during the First World War while Simeis was not in communication with the Rechen-Institut for long periods of time were given provisional designations containing the Greek letter SIGMA. These are here abbreviated S. Reference: DISCOVERY.DB Last Updated: 2003-08-29 [ show close-approach data ] Alternate Designations  A915 RR = 1950 BS = 1951 JJ  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-23 17:34 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin