2005 PR21
compiled by Wm. Robert Johnston
last updated 26 November 2008
Orbital elements and other data (Assumed or derived values in parenthesis, my estimates in italics and parenthesis. Source identifications in brackets, see this link for sources):
orbital data, primary (osculating elements) [JPL]:
|
semimajor axis a: |
44.3364695 AU
| |
orbital period P: |
295.22 y (=107,830.3 d)
| |
eccentricity e: |
0.1061571
| |
perihelion distance q: |
39.6298385 AU
| |
aphelion distance Q: |
49.0431005 AU
| |
inclination i: |
1.33732°
| |
argument of perihelion omega: |
312.36046°
| |
ascending node OMEGA: |
339.12114°
| |
mean anomaly M: |
39.40456°
| |
perihelion passage TP: |
1976-01-20.2
| |
Epoch: |
14 MAY 2008
| |
data arc: |
2005-2007 (21 obs.)
|
orbital data, secondary:
|
semimajor axis a: |
(3,700 km separation) [I8925]
| |
semimajor axis/primary radius a/Rp: |
(30?)
| |
orbital period P: |
(~20 d?)
| |
eccentricity e: |
?
| |
other data, primary:
|
diameter: |
(238 km?)
| |
absolute magnitude H: |
6.0 [JPL]
| |
rotation period: |
?
| |
amplitude delta M: |
?
| |
color index B-V: |
?
| |
color index V-R: |
?
| |
color index B-R: |
?
| |
color index R-I: |
?
| |
slope parameter G: |
(0.15) assumed
| |
geometric albedo: |
(0.09) assumed
| |
mass: |
?
| |
density: |
?
| |
type: |
?
|
other data, secondary:
|
diameter: |
(143 km?)
| |
diameter ratio Ds/Dp: |
(0.60)
| |
component magnitude difference: |
1.1 [I8925]
| |
rotation period: |
?
|
|
--2005 PR21--discovery and notes:
Primary discovered 9 August 2005 from Cerro Tololo Observatory, La Serena.
Companion discovered by K. S. Noll, W. M. Grundy, S. D. Kern, H. F. Levison, and D. C. Stephens from Hubble Space Telescope observations on 20 May 2007, announced 4 March 2008.
--Links, more technical:
--Links, less technical:
--Links to ADS abstracts:
© 2008 by Wm. Robert Johnston.
Last modified 26 November 2008.
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