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2212 Hephaistos (1978 SB)
Classification: Apollo [NEO]          SPK-ID: 2002212
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

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For accurate long-term ephemerides, please instead use our Horizons system.This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances.


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Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB
Reference: JPL 456 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .8376666899459009 2.798e-08  
a 2.159195572535234 5.3892e-09 au
q .3505093643438003 6.0471e-08 au
i 11.55177703381632 5.7748e-06 deg
node 27.53023967518319 1.9975e-05 deg
peri 209.3949522884404 1.979e-05 deg
M 48.90011265950824 5.7109e-06 deg
tp 2458843.085854098266
(2019-Dec-25.58585410)
1.7943e-05 TDB
period 1158.874477840398
3.17
4.3387e-06
1.188e-08
d
yr
n .3106462407135518 1.163e-09 deg/d
Q 3.967881780726668 9.9036e-09 au
  Orbit Determination Parameters
   # obs. used (total)      2603  
   data-arc span      15316 days (41.93 yr)  
   first obs. used      1978-09-27  
   last obs. used      2020-09-02  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .42741  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Sep-03 06:34:15  

Additional Information
 Earth MOID = .115888 au 
 Jupiter MOID = 1.16219 au 
 T_jup = 3.099 
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Orbital Elements at Epoch 2456225.5 (2012-Oct-25.0) TDB
Reference: JPL 456 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .8374227870987458 2.8042e-08  
q .3514385452195887 6.065e-08 au
tp 2456524.755835581342
(2013-Aug-20.25583558)
1.2917e-05 TDB
node 27.697958581809 1.9871e-05 deg
peri 209.1836223344577 1.9686e-05 deg
i 11.57573676348545 5.784e-06 deg
  Orbit Determination Parameters
   # obs. used (total)      2603  
   data-arc span      15316 days (41.93 yr)  
   first obs. used      1978-09-27  
   last obs. used      2020-09-02  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-N16  
   condition code      0  
   norm. resid. RMS      .42741  
   source      ORB  
   producer      Otto Matic  
   solution date      2020-Sep-03 06:34:15  

Additional Information
 Jupiter MOID = 1.16219 au 
 T_jup = 3.099 
Orbit Covariance (6×6)
  e q tp node peri i
e 7.863362695848466E-16 -1.700552621111194E-15 4.233339352672332E-14 3.922369772051784E-14 -4.092341439168551E-14 2.157315772566775E-14
q -1.700552621111194E-15 3.678432924724105E-15 -8.69444068500844E-14 -8.56920608110287E-14 8.974308053079015E-14 -4.649641432393338E-14
tp 4.233339352672332E-14 -8.69444068500844E-14 1.668508304525543E-10 1.955201574379751E-11 -3.283179334092348E-12 1.197515237344857E-11
node 3.922369772051784E-14 -8.56920608110287E-14 1.955201574379751E-11 3.948636435253844E-10 -3.857037617707497E-10 5.618614321054832E-11
peri -4.092341439168551E-14 8.974308053079015E-14 -3.283179334092348E-12 -3.857037617707497E-10 3.875303191160948E-10 -5.432020999201778E-11
i 2.157315772566775E-14 -4.649641432393338E-14 1.197515237344857E-11 5.618614321054832E-11 -5.432020999201778E-11 3.345464100639152E-11

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. 2019-August); 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 5849Last Updated: 2006-03-21

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