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7 Iris (A847 PA)
Classification: Main-belt Asteroid          SPK-ID: 2000007
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]

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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.

Orbital Elements at Epoch 2459396.5 (2021-Jul-01.0) TDB
Reference: JPL 117 (heliocentric ecliptic J2000)
 Element Value Uncertainty (1-sigma)   Units 
e .2294021023644704 1.988e-08  
a 2.386199137464796 2.0867e-09 au
q 1.838800038670086 4.731e-08 au
i 5.518078149365985 2.5788e-06 deg
node 259.5265209801529 2.6413e-05 deg
peri 145.3120195887101 2.708e-05 deg
M 353.1265064147631 7.1145e-06 deg
tp 2459422.205939695297
2.663e-05 TDB
period 1346.35148422678
n .2673893141706237 3.5075e-10 deg/d
Q 2.933598236259507 2.5654e-09 au
  Orbit Determination Parameters
   # obs. used (total)      5241  
   # delay obs. used      1  
   # Doppler obs. used      0  
   data-arc span      62897 days (172.20 yr)  
   first obs. used      1848-08-23  
   last obs. used      2020-11-06  
   planetary ephem.      DE441  
   SB-pert. ephem.      SB441-N16  
   condition code      0  
   norm. resid. RMS      .38622  
   source      ORB  
   producer      Otto Matic  
   solution date      2021-Aug-25 06:07:03  

Additional Information
 Earth MOID = .851023 au 
 Jupiter MOID = 2.47626 au 
 T_jup = 3.493 
[ 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 5.60   n/a MPO636060 IRAS observations used: 18
diameter diameter 199.83 km 10.0 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 18
rotation period rot_per 7.139 h n/a LCDB (Rev. 2020-October); Warner et al., 2009 Published Reference List:
[Groeneveld, I.; Kuiper, G.P. (1954) Astrophys. J. 120, 200-220.]
[Cailliate, C. (1956) Publ. Observ. Lyon 3, fasc. 28.]
[Van Houten-Groeneveld, I.; van Houten, C.J. (1958) Astrophys. J. 127, 253-273.]
[Chang, Y.C.; Chang, C.-s. (1963) Acta Astron. Sin. 11, 139-149.]
[Taylor, R.C. (1977) Astron. J. 82, 441-444.]
[Zhou, X.-z.; Yang, X.-y.; Wu, Z.-x. (1982) Acta Astron. Sin. 23, 349-352; Chin. Astron. Astrophys. 7, 129-131 (1983, 1983ChA...7..129Z).]
[Magnusson, P. (1986) Icarus 68, 1-39.]
[Lagerkvist, C.I.; Magnusson, P.; Williams, I.P.; Buontempo, M.E.; et al. (1989) Astron. Astrophys. Suppl. Ser. 78, 519-532.]
[De Angelis, G. (1995) Planet. Space Sci. 43, 649-682.]
[Kaasalainen, M.; Torppa, J.; Piironen, J. (2002) Icarus 159, 369-395.]
[Behrend, R. (2010) Observatoire de Geneve web site,]
[Ostro, S.J.; Magri, C.; Benner, L.A.M.; Giorgini, J.D.; et al. (2010) Icarus 207, 285-294.]
[Durech, J.; Kaasalainen, M.; Herald, D.; Dunham, D.; et al. (2011) Icarus 214, 652-670.]
[Behrend, R. (2013) Observatoire de Geneve web site,]
[Hanus, J.; Marchis, F.; Durech, J. (2013) Icarus 226, 1045-1057.]
[Behrend, R. (2015) Observatoire de Geneve web site,]
[Hanus, J.; Durech, J.; Oszkiewicz, D.A.; Behrend, R.; et al. (2016) Astron. Astrophys. 586, A108.]
[Behrend, R. (2017) Observatoire de Geneve web site,]
[Viikinkoski, M.; Hanus, J.; Kaasalainen, M.; Marchis, F.; Durech, J. (2017) Astron. Astrophys. 607, A117.]
[Hanuš, J.; Marsset, M.; Vernazza, P.; Viikinkoski, M.; et al. (2019) Astron. Astrophys. 624, A121.]
[Pal, A.; Szakats, R.; Kiss, C.; Bodi, A.; et al. (2019) Ap. J. Supl. Ser. 247, id.26.]
geometric albedo albedo 0.2766   0.030 IRAS-A-FPA-3-RDR-IMPS-V6.0 IRAS observations used: 18
B-V BV 0.855   0.021 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=13; phase (min.=4.28, mean=18.27, max.=32.31) deg.
U-B UB 0.484   0.047 EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 #obs=12; phase (min.=5.26, mean=19.43, max.=32.31) deg.
Tholen spectral type spec_T S   n/a EAR-A-5-DDR-TAXONOMY-V4.0 used 7 color indices; used ground-based radiometric albedo
SMASSII spectral type spec_B S   n/a EAR-A-5-DDR-TAXONOMY-V4.0 based on a high-resolution spectrum by Xu et al. (1995) or Bus and Binzel (2002)

7 Iris (A847 PA)          Discovered 1847-Aug-13 by Hind, J. R. at London
Reference: DISCOVERY.DBLast Updated: 2003-08-29
Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Discovery Circumstances ]
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