148780 Altjira

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(148780) Altjira
Discovery
Discovery site Deep Ecliptic Survey at Kitt Peak[1]
Discovery date October 20, 2001 and
March, 2007 (secondary)[2]
Designations
MPC designation (148780) Altjira
2001 UQ18
Minor planet category Cubewano (DES)[3]
Orbital characteristics[1]
Epoch August 27, 2011 (JD 2455800.5)
Aphelion 47.166 AU
Perihelion 41.78 AU
44.474 AU
Eccentricity 0.0605
296.59 a (108,331 d)
112.0°
Inclination 5.1951°
1.769°
304.4°
Known satellites 1
Physical characteristics
Dimensions ≈128–200 (primary)[4] and 100–180 km (secondary)
Mass 3.952×1018 kg[4]
Mean density
0.5–2.0 g/cm3[4]
Albedo 0.06–0.14[4]
5.76,[1] 5.6,[5] 5.4,[2] or 5.1[2] (primary)
secondary's magnitude difference with primary's: 0.7 ± 0.2[2]

148780 Altjira /ælˈɪrə/ is a binary classical Kuiper belt object (cubewano).[2] The secondary, S/2007 (148780) 1, is large compared to the primary, 140 kilometres (87 mi) vs. 160 kilometres (99 mi).[4] The Altjiran lightcurve is quite flat (Δmag<0.10), which is indicative of a "quasi-spherical body with a homogeneous surface".[5]

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.[4]

It was named after the Arrernte creation deity, Altjira, who created the Earth during the Dreamtime and then retired to the sky.

References[edit]

  1. ^ a b c "JPL Small-Body Database Browser: 148780 Altjira (2001 UQ18)". 2008-10-02 last obs. Retrieved 2011-11-29.  Check date values in: |date= (help)
  2. ^ a b c d e Johnston's Archive on (148780) Altjira Retrieved 2011-11-29
  3. ^ Marc W. Buie. "Orbit Fit and Astrometric record for 148780". SwRI (Space Science Department). Retrieved 2011-11-29. 
  4. ^ a b c d e f 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" (pdf). Icarus 213 (2): 678. arXiv:1103.2751. Bibcode:2011Icar..213..678G. doi:10.1016/j.icarus.2011.03.012.  edit
  5. ^ a b Transneptunian objects and Centaurs from light curves