(148780) Altjira

compiled by Wm. Robert Johnston
last updated 3 November 2012

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: 44.507065 AU
orbital period P: 296.93 y (=108,453.1 d)
eccentricity e: 0.0587494
perihelion distance q: 41.892301 AU
aphelion distance Q: 47.121828 AU
inclination i: 5.19855°
argument of perihelion omega: 304.434°
ascending node OMEGA: 1.8449°
mean anomaly M: 113.423°
perihelion passage TP: 1919 MAR 13.2
Epoch: 30.0 SEP 2012
data arc: 2001-2008 (70 obs.)

orbital data, secondary:
semimajor axis a: 9,904 ± 56 km [G11b]
semimajor axis/primary radius a/Rp: (60?)
orbital period P: 139.561 ± 0.047 [G11b]
eccentricity e: 0.3445 ± 0.0045 [G11b]
inclination i: 35.19° ± 0.19° [G11b]
ascending node OMEGA: 312.73° ± 0.31° [G11b]
longitude of periapsis: 101.96° ± 0.91° [G11b]
mean longitude at epoch: 224.89° ± 0.16° [G11b]
Epoch: 18.5 JUL 2007 [G11b]

other data, primary:
diameter: (340 km?)
absolute magnitude H: 5.44 ± 1.57 [JPL]
5.1 [N07a]
rotation period: ?
amplitude delta M: ?
color index B-V: ?
color index V-R: ?
color index B-R: 1.65
color index R-I: ?
slope parameter G: (0.15) assumed
geometric albedo: (0.09) assumed
mass: (3.952 ± 0.067)x1018 kg [G11b]
density: ?
type: ?

other data, secondary:
diameter: (246 km?)
diameter ratio Ds/Dp: (0.72)
component magnitude difference: 0.7 ± 0.2 [N07a]
rotation period: ?

--(148780) Altjira--discovery and notes:

Primary discovered 20 October 2001 by M. W. Buie at Kitt Peak, United States. Alternate designation 2001 UQ18.

Companion reported March 2007.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2007-2008, 2012 by Wm. Robert Johnston.
Last modified 3 November 2012.
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