486958 Arrokoth

486958 Arrokoth
Grayscale composite image of Arrokoth
Discovery [1][2]
Discovered by
Discovery siteHubble Space Telescope
Discovery date26 June 2014
Designations
(486958) Arrokoth
Pronunciation/ˈærəkɒθ/
Named after
Powhatan word arrokoth, glossed 'sky' but probably meaning 'cloud'
  • (486958) 2014 MU69
  • Ultima Thule (unofficial)[3]
  • 1110113Y
  • PT1
Orbital characteristics[2][5]
Epoch 27 April 2019 (JD 2458600.5)
Uncertainty parameter 2
Observation arc2.33 yr (851 days)
Aphelion46.442 AU
Perihelion42.721 AU
44.581 AU
Eccentricity0.04172
297.67 yr
316.551°
0° 0m 11.92s / day
Inclination2.4512°
158.998°
174.418°
Physical characteristics
DimensionsOverall best fit:
35.95 × 19.90 × 9.75 km[6]
Wenu 21.20 × 19.90 × 9.05 km[6]
Weeyo 15.75 × 13.85 × 9.75 km[6]
Overall volume equivalent: 18.26 km[6]
Wenu 15.86 km[6]
Weeyo 12.79 km[6]
Volume3185 km3[6]
Mass~ 7.485×1014 kg (assumed nominal density)[6]
Mean density
~ 0.235 g/cm3 (nominal)
1-sigma range: 0.155–0.600 g/cm3[6]
Equatorial surface gravity
~ 0.0001 g
~ 0.001 m/s2[7]: 28:45 
15.9380±0.0005 h[8]
99.3°[9]
North pole right ascension
317.5°±[10]
North pole declination
−24.89°±[10][9]
0.21+0.05
−0.04
(geometric)[11]
0.062±0.015 (Bond)[11]
Surface temp. min mean max
(approx) 29 K 42 K 60 K
V−I=1.35[12]
G−I=1.42±0.14[13]
G−R=0.95±0.14[13]
26.6[12]
10.4 (V-band)[11]

486958 Arrokoth (provisional designation 2014 MU69; formerly nicknamed Ultima Thule[a]) is a trans-Neptunian object located in the Kuiper belt. Arrokoth became the farthest and most primitive object in the Solar System visited by a spacecraft when the NASA space probe New Horizons conducted a flyby on 1 January 2019.[17][18][19] Arrokoth is a contact binary 36 km (22 mi) long, composed of two planetesimals 21 and 15 km (13 and 9 mi) across, that are joined along their major axes. With an orbital period of about 298 years and a low orbital inclination and eccentricity, Arrokoth is classified as a cold classical Kuiper belt object.

Arrokoth was discovered on 26 June 2014 by astronomer Marc Buie and the New Horizons Search Team using the Hubble Space Telescope as part of a search for a Kuiper-belt object for New Horizons to target in its first extended mission; it was chosen over two other candidates, 2014 OS393 and 2014 PN70, to become the primary target of the mission.[20]

  1. ^ a b Cite error: The named reference jpldata was invoked but never defined (see the help page).
  2. ^ a b c Cite error: The named reference MPC-object was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Ultima Thule was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Buie-DES was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference MPC-486958 was invoked but never defined (see the help page).
  6. ^ a b c d e f g h i Cite error: The named reference Keane2022 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference LPSC-2019-03-21 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Buie2020 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference EPSC-DPS2019-311 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference aay3999 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Hofgartner2020 was invoked but never defined (see the help page).
  12. ^ a b Cite error: The named reference Benecchi2019b was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Thirouin2019 was invoked but never defined (see the help page).
  14. ^ "Thule". Oxford English Dictionary (Online ed.). Oxford University Press. September 2022. Retrieved 29 December 2020. (Subscription or participating institution membership required.)
  15. ^ "New Horizons Press Kit" (PDF). Applied Physics Laboratory. December 2018. p. 5. Retrieved 1 January 2019.
  16. ^ "New Horizons: First Images of Ultima Thule". YouTube. Applied Physics Laboratory. 1 January 2019. Archived from the original on 14 November 2021.
  17. ^ Cite error: The named reference explored was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference about was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference LPSC1611 was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference lauer-sciam was invoked but never defined (see the help page).


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