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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 2459200.5 (2020-Dec-17.0) TDB
Reference: JPL 95 (heliocentric ecliptic J2000)
| Element | Value | Uncertainty (1-sigma) | Units |
| e | .2337277240524353 | 1.6762e-08 | |
| a | 2.771168818670789 | 6.8145e-09 | au |
| q | 2.12346983771779 | 4.6884e-08 | au |
| i | 1.382268099524335 | 7.4419e-07 | deg |
| node | 346.9768620705862 | 3.3562e-05 | deg |
| peri | 39.3811067517983 | 3.5057e-05 | deg |
| M | 23.06992076938688 | 3.183e-06 | deg |
| tp | 2459092.521695302642
(2020-Aug-31.02169530) | 1.4789e-05 | TDB |
| period | 1684.972830189824
4.61 | 6.2152e-06
1.702e-08 | d
yr |
| n | .2136532966881392 | 7.8808e-10 | deg/d |
| Q | 3.418867799623788 | 8.4072e-09 | au |
|
| | Orbit Determination Parameters
Additional Information
|
[ show covariance matrix ]
Physical Parameter Table
| Parameter |
Symbol |
Value |
Units |
Sigma |
Reference |
Notes |
| absolute magnitude |
H |
9.68 |
|
n/a |
E2021B10 |
IRAS observations used: 12 |
| diameter |
diameter |
69.049 |
km |
0.649 |
urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2014ApJ...791..121M) |
|
| rotation period |
rot_per |
13.856 |
h |
n/a |
LCDB (Rev. 2020-October); Warner et al., 2009 |
Published Reference List:
[Wetterer, C.J.; Saffo, C.R.; Majcen, S.; Tompkins, J. (1999) Minor Planet Bull. 26, 30-31.]
[Pilcher, F. (2012) Minor Planet Bull. 39, 57-60.]
[Pilcher, F. (2013) Minor Planet Bull. 40, 161-163.]
[Behrend, R. (2020) Observatoire de Geneve web site, http://obswww.unige.ch/~behrend/page_cou.html] |
| geometric albedo |
albedo |
0.022 |
|
0.007 |
urn:nasa:pds:neowise_diameters_albedos::2.0[mainbelt] (http://adsabs.harvard.edu/abs/2016AJ....152...63N) |
|
| B-V |
BV |
0.730 |
|
0.030 |
EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 |
#obs=2; phase (min.=6.23, mean=6.27, max.=6.30) deg. |
| U-B |
UB |
0.350 |
|
0.040 |
EAR-A-5-DDR-UBV-MEAN-VALUES-V1.2 |
#obs=2; phase (min.=6.23, mean=6.27, max.=6.30) deg. |
| Tholen spectral type |
spec_T |
C: |
|
n/a |
EAR-A-5-DDR-TAXONOMY-V4.0 |
used 2 color indices |
| SMASSII spectral type |
spec_B |
Ch |
|
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) |
|
| 177 Irma (A877 VA) Discovered 1877-Nov-05 by Henry, Paul at Paris |
| In their cooperative program it will probably never be known which of the Henry brothers discovered which planet. With strict impartiality, these discoveries were announced as having been made alternatively by Prosper and by Paul. |
| Note: "planet" implies "minor planet" |
| Reference: DISCOVERY.DB | Last Updated: 2003-08-29 |
|
Alternate Designations
| A877 VA = 1937 UA = 1962 DB = A900 UB = A900 VA = A912 HE |
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