148780 Altjira

Binary Kuiper belt object From Wikipedia, the free encyclopedia

148780 Altjira (provisional designation 2001 UQ18) appears to be a triple or contact binary double classical Kuiper belt object.[7] The secondary is large compared to the primary, approximately 246 kilometres (153 mi) vs. 221 kilometres (137 mi).[3] The lightcurve is quite flat (Δmag < 0.10), which is indicative of a "quasi-spherical body with a homogeneous surface".[8] The system mass is 4×1018 kg.[4]

DiscoverysiteDeep Ecliptic Survey at Kitt Peak[1]
Discoverydate20 October 2001
(148780) Altjira
Pronunciation/ælˈtʃɪərə/
Quick facts Discovery, Discovery site ...
(148780) Altjira
Altjira and its companion imaged by the Hubble Space Telescope in 2006
Discovery
Discovery siteDeep Ecliptic Survey at Kitt Peak[1]
Discovery date20 October 2001
Designations
(148780) Altjira
Pronunciation/ælˈtʃɪərə/
Named after
Altjira
2001 UQ18
Classical KBO (DES)[2]
Orbital characteristics[1]
Epoch 2025 May 05 (JD 2460800.5)
Uncertainty parameter 4
Observation arc7,709 days (21.11 yr)
Aphelion47.11 AU (7.048 Tm)
Perihelion42.00 AU (6.283 Tm)
44.55 AU (6.665 Tm)
Eccentricity0.0573
297.40 yr (108626±31 d)
129°
0.003314°/day
Inclination5.198°
1.84°
1919 Feb 16 ±37 days
304°
Known satellites1 confirmed, 1 suspected
Physical characteristics
  • 331+51
    −187     km     (combined)
  • 246+38
    −139     km     (primary)[3]
Mass(3.952±0.067)×1018 kg (system)[4] 2.338×1018 kg (primary)[5]
Mean density
0.30+0.50
−0.14 g/cm3[3]
0.0430+0.1825
−0.0095[3]
  • B−V = 0.91±0.13
  • V−R = 0.74±0.08
  • V−I = 1.17±0.09[6]
  • 5.77;[1]
  • 5.4 (system), 5.1 (primary) [7]
Close

In 2008, Altjira was named after the Arrernte creation deity, Altjira (Alchera).[1]

Satellite

Quick facts Discovery, Discovery date ...
(satellite)
Discovery
Discovery date6 August 2006[7]
Orbital characteristics[4]
9904±56 km
Eccentricity0.3445±0.0045
139.561±0.047 d
Inclination35.19°±0.19° (retrograde)
Satellite of148780 Altjira
Physical characteristics
221+34
−125 km[3]
Mass1.695×1018 kg[9]
difference from primary: 0.7±0.2[7]
Close

Its companion was discovered on 6 August 2006, from images taken by the Hubble Space Telescope.[10] The secondary's orbit has the following parameters: semi-major-axis, 9904±56 km; period, 139.561±0.047 d; eccentricity, 0.3445±0.0045; and inclination, 35.19°±0.19° (retrograde). There is indirect evidence that Altjira may be an unresolved hierarchical triple system.[11]

See also

References

External links

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