+ View the NASA Portal + Center for Near-Earth Object Studies JPL Small-Body Database Browser Search: [ help ]   2212 Hephaistos (1978 SB) Classification: Apollo [NEO]          SPK-ID: 2002212 [ 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 496 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .8376666929978114 2.7375e-08   a 2.159195572083737 5.356e-09 au q .3505093576808355 5.9149e-08 au i 11.55177720319622 5.7582e-06 deg node 27.5302439807015 1.7823e-05 deg peri 209.3949487284987 1.7688e-05 deg M 48.90011278743508 5.707e-06 deg tp 2458843.085853735831 (2019-Dec-25.58585374) 1.7932e-05 TDB period 1158.874477476909 3.17 4.312e-06 1.181e-08 d yr n .3106462408109881 1.1559e-09 deg/d Q 3.967881786486638 9.8426e-09 au   Orbit Determination Parameters    # obs. used (total)      2910      data-arc span      15453 days (42.31 yr)      first obs. used      1978-09-27      last obs. used      2021-01-17      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      norm. resid. RMS      .41976      source      ORB      producer      Otto Matic      solution date      2021-Jan-18 06:07:43   Additional Information  Earth MOID = .115888 au   Jupiter MOID = 1.16219 au   T_jup = 3.099  [ 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 13.3   n/a MPO502174   diameter diameter 5.7 km n/a Hazards due to Comets and Asteroids (1994), Ed. T. Gehrels, pp.540-543 based on assumed medium albedo (0.15) rotation period rot_per 20. h n/a LCDB (Rev. 2020-October); Warner et al., 2009 lower-limit; Result based on fragmentary lightcurve(s), may be completely wrong. Published Reference List: [Pravec, P.; Wolf, M.; Sarounova, L.; Mottola, S.; et al. (1997) Icarus 130, 275-286.] geometric albedo albedo 0.163   0.027 urn:nasa:pds:neowise_diameters_albedos::2.0[neos] (http://adsabs.harvard.edu/abs/2011ApJ...743..156M)   B-V BV 0.766   0.037 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=2; phase (min.=15.38, mean=15.38, max.=15.38) deg. U-B UB 0.397   0.031 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=1; phase=15.38 deg. Tholen spectral type spec_T SG   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 2 color indices 2212 Hephaistos           Discovered 1978 Sept. 27 by L. I. Chernykh at the Crimean Astrophysical Observatory. This Apollo-type object is named for the god of fire and blacksmiths. NOTE: some special characters may not display properly (any characters within {} are an attempt to place the proper accent above a character) Reference: MPC 5849 Last Updated: 2006-03-21 [ show close-approach data ] [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ] 2021-Jan-19 00:11 UT (server date/time)   Site Manager:   Ryan S. Park Webmaster:   Alan B. Chamberlin