Astronomy:148780 Altjira
From HandWiki
 Altjira and its companion imaged by the Hubble Space Telescope in 2006 | |
| Discovery | |
|---|---|
| Discovery site | Deep Ecliptic Survey at Kitt Peak[1] |
| Discovery date | 20 October 2001 |
| Designations | |
| (148780) Altjira | |
| Pronunciation | /ælˈtʃɪərə/ |
| Named after | Altjira |
| 2001 UQ18 | |
| Minor planet category | 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) |
| |{{{apsis}}}|helion}} | 47.11 astronomical unit|AU (7.048 Tm) |
| |{{{apsis}}}|helion}} | 42.00 AU (6.283 Tm) |
| 44.55 AU (6.665 Tm) | |
| Eccentricity | 0.0573 |
| Orbital period | 297.40 yr (108626±31 d) |
| Mean anomaly | 129° |
| Mean motion | 0.003314°/day |
| Inclination | 5.198° |
| Longitude of ascending node | 1.84° |
| |{{{apsis}}}|helion}} | 1919 Feb 16 ±37 days |
| 304° | |
| Known satellites | 1 confirmed, 1 suspected |
| Physical characteristics | |
| Mean diameter | |
| Mass | (3.952±0.067)×1018 kg (system)[4] |
| Mean density | 0.30+0.50 −0.14 g/cm3[3] |
| Geometric albedo | 0.0430+0.1825 −0.0095[3] |
| |
| Absolute magnitude (H) | |
| Discovery | |
|---|---|
| Discovery date | 6 August 2006[6] |
| Orbital characteristics[4] | |
| 9904±56 km | |
| Eccentricity | 0.3445±0.0045 |
| Orbital period | 139.561±0.047 d |
| Inclination | 35.19°±0.19° (retrograde) |
| Satellite of | 148780 Altjira |
| Physical characteristics | |
| Mean diameter | 221+34 −125 km[3] |
| Absolute magnitude (H) | 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]
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
- 47171 Lempo – the first and only confirmed hierarchical triple system in the Kuiper belt
- 58534 Logos – a contact binary and potential triple system in the cold classical Kuiper belt
References
- ↑ 1.0 1.1 1.2 1.3 "JPL Small-Body Database Browser: 148780 Altjira (2001 UQ18)". https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=148780. Retrieved 2025-08-26.
- ↑ Marc W. Buie. "Orbit Fit and Astrometric record for 148780". SwRI (Space Science Department). https://www.boulder.swri.edu/~buie/kbo/astrom/148780.html. Retrieved 2011-11-29.
- ↑ 3.0 3.1 3.2 3.3 3.4 Vilenius, E. 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. doi:10.1051/0004-6361/201322416. Bibcode: 2014A&A...564A..35V.
- ↑ 4.0 4.1 4.2 Grundy, W. M.; Noll, K. S.; Nimmo, F.; Roe, H. G.; Buie, M. W.; Porter, S. B.; Benecchi, S. D.; Stephens, D. C. et al. (2011). "Five new and three improved mutual orbits of transneptunian binaries". Icarus 213 (2): 678. doi:10.1016/j.icarus.2011.03.012. Bibcode: 2011Icar..213..678G.
- ↑ 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. doi:10.1016/j.icarus.2004.09.009. Bibcode: 2005Icar..174...90D.
- ↑ 6.0 6.1 6.2 6.3 Johnston's Archive on (148780) Altjira Retrieved 2011-11-29
- ↑ 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. doi:10.1051/0004-6361/200912601. Bibcode: 2009A&A...505.1283D.
- ↑ "(148780) Altjira = 2001 UQ18". https://minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=148780.
- ↑ 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. doi:10.3847/PSJ/ad864d.
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