Asteroids with Satellites Database--Johnston's Archive

(148780) Altjira

compiled by Wm. Robert Johnston
last updated 10 May 2014
under construction--testing upgrades!

--Orbital and physical data--

(See this page for definitions of quantities; source codes in brackets, see this link for full references; *A, *D, and *E indicate assumed, derived, and estimated values, respectively.)

dynamical type, primary: TNO, Cubewano


orbital data, primary (osculating elements) [JPL] :
semimajor axis a: 44.4009 AU
orbital period P: 295.867 yr (= 108065.4 d)
eccentricity e: 0.05814
perihelion distance q: 41.819 AU
aphelion distance Q: 46.9826 AU
inclination i: 5.20380°
argument of perihelion ω: 301.36°
ascending node Ω: 1.9671°
mean anomaly M: 118.61°
perihelion passage TP: 1916 Nov 28
Epoch: 2014 May 23
data arc: 2001-2008 (70 obs.)
Earth MOID: 40.8064 AU
Jupiter Tisserand invariant TJ: 5.926
Neptune Tisserand invariant TN:3.09 [*D]


orbital data, secondary:
semimajor axis as: 9904 ± 56 km [G11a]
separation/primary radius as/rp:81 [*D]
separation/Hill radius as/rH:0.018 [*D]
orbital period Ps: 139.561 ± 0.047 d [G11a]
eccentricity es: 0.3445 ± 0.0045 [G11a]
inclination is:35.19°± 0.19 [G11a]
ascending node Ωs:312.73°± 0.31 [G11a]
argument of pericenter ωs:101.96°± 0.91 [G11a]
mean anomaly M:224.89°± 0.16 [G11a]
Epoch:2007 Jul 18.5
normalized ang. mom. αL: ?

other data, system (combined):
absolute mag. H: 5.7 [MPC]
6.44 ± 0.14 [V14a]
slope parameter G: 0.15 [*A]
effective diameter dE: 331 ± 51/187 km [V14a]
geometric albedo: 0.043 ± 0.182/0.01 [V14a]
color index U-B: ?
color index B-V: 0.91 [**D05]
color index V-R:0.74± 0.08 [**D05]
color index B-R:1.65 [**D05]
color index V-I:1.17± 0.09 [**D05]
taxonomic type: ?
mass m: 3.99x1018 ± 6.7x1016 kg [G11a]
density ρ: 0.3 ± 0.5/0.14 g/cm3 [V14a]
Hill radius rH: 550000 km [*D]

other data, primary:
diameter dp: 246 ± 38/139 km [V14a]
color index V-I:1.3± 0.16 [B08d]
rotation period RPp: ?
amplitude in mag., rotational ΔM: ?
pole direction : ? ; ?


other data, secondary:
diameter ds: 221 ± 34/125 km [V14a]
diameter ratio ds/dp: 0.899 [G11a]
component mag. difference ΔM: 0.7 ± 0.2 [*N07a]
color index V-I:1.39± 0.17 [B08d]
rotation period RPs: ?

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

Primary discovered 2001 Oct 20 from Kitt Peak Observatory, Arizona, USA by Deep Ecliptic Survey. Alternate designation(s): 2001 UQ18 . Permanent number assigned 2007 Feb 02.

Named 2008 Jul 18 for the mythological Aboriginal god of the sky [MPC63642].

Companion discovered 2006 Aug 06 using HST observations from Hubble Space Telescope. Announced 2007 Mar 14.

--Links, more technical:

--Links, less technical:

--Links to ADS abstracts:


© 2007-2012, 2014 by Wm. Robert Johnston.
Last modified 10 May 2014.
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