148780 Altjira

Last updated
(148780) Altjira
148780-altjira-hubble.jpg
Altjira and its companion imaged by the Hubble Space Telescope in 2006
Discovery
Discovery site Deep 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 arc 7,709 days (21.11 yr)
Aphelion 47.11  AU (7.048  Tm)
Perihelion 42.00 AU (6.283 Tm)
44.55 AU (6.665 Tm)
Eccentricity 0.0573
297.40 yr (108626±31 d)
129°
0.003314°/day
Inclination 5.198°
1.84°
1919 Feb 16 ±37 days
304°
Known satellites 1 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]
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 [5]
  • 5.77; [1]
  • 5.4 (system), 5.1 (primary) [6]
    Satellite
    Discovery
    Discovery date6 August 2006 [6]
    Orbital characteristics [4]
    9904±56 km
    Eccentricity 0.3445±0.0045
    139.561±0.047 d
    Inclination 35.19°±0.19° (retrograde)
    Satellite of 148780 Altjira
    Physical characteristics
    221+34
    −125     km     [3]
    difference from primary: 0.7±0.2 [6]

      148780 Altjira (provisional designation 2001 UQ18) appears to be a triple or contact binary double classical Kuiper belt object. [6] 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". [7] The system mass is 4×1018 kg. [4]

      Contents

      Its companion was discovered on 6 August 2006, from images taken by the Hubble Space Telescope. [8] 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. [9]

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

      See also

      References

      1. 1 2 3 4 "JPL Small-Body Database Browser: 148780 Altjira (2001 UQ18)" (2022-11-28 last obs). Retrieved 2025-08-26.
      2. ↑ Marc W. Buie. "Orbit Fit and Astrometric record for 148780". SwRI (Space Science Department). Retrieved 2011-11-29.
      3. 1 2 3 4 5 Vilenius, E.; Kiss, C.; Mommert, M.; et al. (2014). ""TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations". Astronomy & Astrophysics. 564: A35. arXiv: 1403.6309 . Bibcode:2014A&A...564A..35V. doi:10.1051/0004-6361/201322416. S2CID   118513049.
      4. 1 2 3 Grundy, W. M.; Noll, K. S.; Nimmo, F.; Roe, H. G.; Buie, M. W.; Porter, S. B.; Benecchi, S. D.; Stephens, D. C.; Levison, H. F.; Stansberry, J. A. (2011). "Five new and three improved mutual orbits of transneptunian binaries". Icarus. 213 (2): 678. arXiv: 1103.2751 . Bibcode:2011Icar..213..678G. doi:10.1016/j.icarus.2011.03.012. S2CID   9571163.
      5. ↑ Doressoundiram, A.; Peixinho, N.; Doucet, C.; Mousis, O.; Barucci, M. A.; Petit, J. M.; Veillet, C. (2005). "The Meudon Multicolor Survey (2MS) of Centaurs and trans-neptunian objects: extended dataset and status on the correlations reported". Icarus. 174 (1): 90–104. Bibcode:2005Icar..174...90D. doi:10.1016/j.icarus.2004.09.009. S2CID   122936619.
      6. 1 2 3 4 Johnston's Archive on (148780) Altjira Retrieved 2011-11-29
      7. ↑ Duffard, R.; Ortiz, J. L.; Thirouin, A.; Santos-Sanz, P.; Morales, N. (2009). "Transneptunian objects and Centaurs from light curves". Astronomy & Astrophysics. 505 (3): 1283–1295. arXiv: 0910.1472 . Bibcode:2009A&A...505.1283D. doi:10.1051/0004-6361/200912601.
      8. ↑ "(148780) Altjira = 2001 UQ18". minorplanetcenter.net. Retrieved 2025-09-03.
      9. ↑ Nelsen, Maia A.; Ragozzine, Darin; Proudfoot, Benjamin C. N.; Giforos, William G.; Grundy, Will (March 2025). "Beyond Point Masses. IV. TNO Altjira is Likely a Hierarchical Triple Discovered Through Non-Keplerian Motion". The Planetary Science Journal. 6 (3): 53. arXiv: 2403.12786 . doi: 10.3847/PSJ/ad864d .
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