+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   801 Helwerthia (A915 FH) Classification: Main-belt Asteroid          SPK-ID: 2000801 [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] [ show orbit diagram ] Orbital Elements at Epoch 2459396.5 (2021-Jul-01.0) TDB Reference: JPL 45 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .07712993525867248 2.0096e-08   a 2.604569495187253 7.5019e-09 au q 2.403679218646746 5.4064e-08 au i 14.12901505655814 5.4115e-07 deg node 185.9524103761406 2.2446e-06 deg peri 335.0351405135281 1.5931e-05 deg M 108.8456016766128 1.3271e-05 deg tp 2458932.294015359093 (2020-Mar-23.79401536) 5.6987e-05 TDB period 1535.332176004992 4.20 6.6333e-06 1.816e-08 d yr n .2344769461789939 1.013e-09 deg/d Q 2.805459771727759 8.0805e-09 au   Orbit Determination Parameters    # obs. used (total)      3168      data-arc span      38812 days (106.26 yr)      first obs. used      1915-03-20      last obs. used      2021-06-23      planetary ephem.      DE441      SB-pert. ephem.      SB441-N16      condition code      0      norm. resid. RMS      .40875      source      ORB      producer      Otto Matic      solution date      2021-Jul-08 11:35:16   Additional Information  Earth MOID = 1.41635 au   Jupiter MOID = 2.1715 au   T_jup = 3.366  [ 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 11.62   n/a MPCxxxxx IRAS observations used: 24 diameter diameter 32.404 km 0.679 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   rotation period rot_per 23.93 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List: [Pilcher, F.; Ferrero, A.; Inasaridze, R.Ya.; Krugly, Y.N.; et al. (2012) Minor Planet Bull. 39, 222-225.] [Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.] geometric albedo albedo 0.031   0.012 urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2012ApJ...759L...8M)   B-V BV 0.727   0.040 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=3.78 deg. U-B UB 0.273   0.064 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=3.78 deg. Tholen spectral type spec_T XC   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices 801 Helwerthia (A915 FH)          Discovered 1915-Mar-20 by Wolf, M. at Heidelberg Reference: DISCOVERY.DB Last Updated: 2003-08-29 Alternate Designations  A915 FH = 1925 RG = 1970 GS1 = A924 OD  [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ] 2021-Jul-18 21:10 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin