Discovery | |
---|---|
Discovery site | Deep Ecliptic Survey at Kitt Peak[1] |
Discovery date | 20 October 2001 August 2006 (secondary)[2] |
Designations | |
(148780) Altjira | |
Pronunciation | /ælˈtʃɪrə/ |
2001 UQ18 | |
Cubewano (DES)[3] | |
Adjectives | Altjirian |
Orbital characteristics[1] | |
Epoch 13 January 2016 (JD 2457400.5) | |
Uncertainty parameter 3 | |
Observation arc | 2539 days (6.95 yr) |
Aphelion | 46.877 AU (7.0127 Tm) |
Perihelion | 41.572 AU (6.2191 Tm) |
44.224 AU (6.6158 Tm) | |
Eccentricity | 0.059979 |
294.10 yr (107421 d) | |
124.29° | |
0.0033513°/day | |
Inclination | 5.2056° |
2.0132° | |
297.71° | |
Known satellites | 1 |
Physical characteristics | |
331+51 −187 km (combined) 246+38 −139 km (primary) 221+34 −125 km (secondary)[4] | |
Mass | 3.952×1018 kg[5] |
Mean density | 0.30+0.50 −0.14 g/cm3[4] |
0.0430+0.1825 −0.0095[4] | |
B−V = 0.91±0.13 V−R = 0.74±0.08 V−I = 1.17±0.09[6] | |
5.7[1] 5.6,[7] 5.4,[2] or 5.1[2] (primary) secondary's magnitude difference with primary's: 0.7 ± 0.2[2] | |
148780 Altjira /ælˈtʃɪrə/ is a binary classical Kuiper belt object (cubewano).[2] The secondary, S/2007 (148780) 1, is large compared to the primary, approximately 246 kilometres (153 mi) vs. 221 kilometres (137 mi).[4] The Altjiran lightcurve is quite flat (Δmag<0.10), which is indicative of a "quasi-spherical body with a homogeneous surface".[7]
The satellite's orbit has the following parameters: semi-major-axis, 9904 ± 56 km; period, 139.561 ± 0.047 days; eccentricity, 0.3445 ± 0.0045; and inclination, 35.19 ± 0.19°(retrograde). The total system mass is about 4 × 1018 kg.[5]
It was named after the Arrernte creation deity, Altjira, who created the Earth during the Dreamtime and then retired to the sky.[1]
Altjira may be an unresolved hierarchical triple system.[8]
TNOsCool-10
was invoked but never defined (see the help page).Doressoundiram2005
was invoked but never defined (see the help page).