(229762) Gǃkúnǁ'hòmdímà

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Asteroid
(229762) Gǃkúnǁ'hòmdímà
Gǃkúnǁ'hòmdímà and his companion through the Hubble Space Telescope (2018).
Gǃkúnǁ'hòmdímà and his companion through the Hubble Space Telescope (2018).
Properties of the orbit ( animation )
Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type SDO
Major semi-axis 72,722  AU
eccentricity 0.484
Perihelion - aphelion 37.502 AU - 107.943 AU
Inclination of the orbit plane 23.4 °
Length of the ascending node 131.1 °
Argument of the periapsis 346.9 °
Time of passage of the perihelion July 10, 2046
Sidereal period 620 a 2 M
Mean orbital velocity 3.265 km / s
Physical Properties
Medium diameter 614 ± 15 km
Dimensions 646 × 598 km
Albedo 0.15 ± 0.016
Rotation period > 8 h , probably 11.05 h
Absolute brightness 3.3 mag
history
Explorer Megan E. Schwamb
Michael E. Brown
David L. Rabinowitz
Date of discovery October 19, 2007
Another name 2007 UK 126
Source: Unless otherwise stated, the data comes from JPL Small-Body Database Browser . The affiliation to an asteroid family is automatically determined from the AstDyS-2 database . Please also note the note on asteroid items.

(229762) Gǃkúnǁ'hòmdímà (pronounced ᶢᵏǃ͡χʼṹ ᵑ̊ǁʰòmdí mà ) is a large Trans-Neptunian object that was discovered in October 2007 (provisional name 2007 UK 126 ). It belongs to the category of scattered disk objects . Because of its size, the asteroid is a dwarf planet candidate . With Gǃò'é ǃHú he has a moon that is about a fifth the diameter of the mother asteroid.

discovery

(229762) Gǃkúnǁ'hòmdímà was discovered on October 19, 2007 by a team of astronomers consisting of Megan E. Schwamb, Michael E. Brown and David L. Rabinowitz at the Palomar Observatory of the California Institute of Technology . The discovery was announced on February 26, 2008. The planetoid was given the provisional designation 2007 UK 126 and on December 31, 2009 by the IAU the minor planet number 229762 .

After its discovery, Gǃkúnǁ'hòmdímà could be identified on photos from August 16, 1982 and thus its orbit calculated more precisely. Since then, the asteroid has been observed through various telescopes such as the Herschel Space Telescope and Earth-based telescopes. In October 2018 there were 178 observations over a period of 37 years.

Surname

It was suggested the name G!kúnǁ'hòmdímà selected from the mythology of the ethnic group of Ju|'hoansi (a group of the San ) in Namibia originates. Their language Juǀ'hoan contains clicks , the special letters for them were adopted in the name. On April 6, 2019, the name was confirmed by the IAU .

properties

The orbit of Gǃkúnǁ'hòmdímà (white) compared to other distant planetoids.

Orbit

Gǃkúnǁ'hòmdímà moves on a strongly elliptical orbit ( orbital eccentricity = 0.48) between 37.50 and 107.94 AU from the sun. The period of rotation is about 620.17 years. The orbit incline is 23.38 °. Apparently, the planetoid was thrown into this eccentric orbit by gravitational interaction with Neptune. It will reach its perihelion in mid-2046, so it should have passed its last around the year 1426. It is currently about 42.3  AU from the Sun.

Both the MPC and Marc Buie ( DES ) classify Gǃkúnǁ'hòmdímà as a Scattered Disc Object .

size

With the help of the Herschel space telescope (instrument PACS), the diameter was determined to be 599 ± 77 km in 2011. At this point in time, no observation data were available from the Spitzer Space Telescope (MIPS instrument), so that the modeling showed corresponding uncertainties. On the occasion of a star occlusion in 2014, it was possible to specify the effective diameter (614 ± 15 km taking into account the geometric projection and Herschel / PACS data, dimensions: 646 km × 598 km based on an elliptical fit for the star cover).

It is likely that Gǃkúnǁ'hòmdímà is in hydrostatic equilibrium due to its size and is therefore largely round. Mike Brown classifies Gǃkúnǁ'hòmdímà as the most likely dwarf planet .

Provisions of the diameter for Gǃkúnǁ'hòmdímà
year Dimensions km source
2007 599.0 ± 77.0 (system) Santos-Sanz et al. a.
2010 801.0 Tancredi
2016 640.0
(686.03 ± 60.23 × 593.63 ± 61.91) 		Schindler et al. a.
2016 638.0 +24.0−12.0 (System) Benedetti-Rossi et al. a.
2017 624.0 (system)
614.0 ± 15.0
(645.80 ± 5.68 × 597.81 ± 12.74) 		Schindler et al. a.
2018 612.0 Brown
The most precise determination is marked in bold .

moon

In 2011, a team of astronomers announced the discovery of a moon about 112 km in diameter (officially known as Gǃò'é ǃHú by analogy with the parent asteroid ), which was discovered through images taken by the Hubble Space Telescope . It orbits Gǃkúnǁ'hòmdímà in 11.3 days at a distance of about 6035 ± 48 km. However, the mass of the system has not yet been calculated.

The Gǃkúnǁ'hòmdímà system at a glance:

Components Physical parameters Path parameters discovery
Surname Throughput
diameter
(km) 		Relative
size
% 		Mass
(kg) 		Major
semi-axis
(km) 		Orbital time
(d) 		eccentricity
 Inclination
to the Gǃkúnǁ'hòmdímà
equator 		Date of discovery
Date of publication
(229762) Gǃkúnǁ'hòmdímà
 614.0 100.00 ? - - - - October 19, 2007
February 26, 2008
Gǃò'é ǃHú
(Gǃkúnǁ'hòmdímà I) 		112.0 18.24 ? 6035 11.31473 0.0236 43.75 ° November 13, 2008
2011

See also

Web links

Commons : (229762) Gǃkúnǁ'hòmdímà  - collection of images, videos and audio files

Individual evidence

  1. ↑ v ≈ π * a / period (1 + sqrt (1-e²))
  2. ↑ a b c d e K. Schindler, J. Wolf, J. Bardecker, A. Olsen, T. Müller, C. Kiss, JL Ortiz, F. Braga-Ribas, JIB Camargo, D. Herald, A. Krabbe: Results from a triple chord stellar occultation and far-infrared photometry of the trans-Neptunian object (229762) 2007 UK 126 . In: Astronomy and Astrophysics . 600, no.A12 , March 20, 2017. arxiv : 1611.02798 . bibcode : 2017A & A ... 600A..12S . doi : 10.1051 / 0004-6361 / 201628620 .
  3. ↑ A. Thirouin, KS Noll, JL Ortiz, N. Morales: Rotational properties of the binary and non-binary populations in the trans-Neptunian belt . In: Astronomy and Astrophysics . 569, No. A3, September 8, 2014. arxiv : 1407.1214 . doi : 10.1051 / 0004-6361 / 201423567 .
  4. ↑ IAU: MPEC 2008-D38: 2007 UK126 . MPC . February 26, 2008. Accessed January 31, 2019.
  5. ↑ (229762) Gǃkúnǁ'hòmdímà in the Small-Body Database of the Jet Propulsion Laboratory (English). Template: JPL Small-Body Database Browser / Maintenance / AltRetrieved June 2, 2018.
  6. ↑ (229762) Gǃkúnǁ'hòmdímà at the IAU Minor Planet Center (English)
  7. ↑ Gǃkúnǁ'hòmdímà and Gǃò'é ǃhú (229762 2007 UK126). Lowell Observatory, accessed January 31, 2019 .
  8. ↑ AstDyS. Universita di Pisa, accessed June 2, 2018 .
  9. ↑ Brian G. Marsden: MPEC 2009-R09: Distant Minor Planets (2009 SEPT 16.0 TT.) . In: IAU Minor Planet Center . September 16, 2009. Accessed January 31, 2019.
  10. ^ Marc W. Buie : Orbit Fit and Astrometric record for 229762 . SwRI (Space Science Department). Accessed January 31, 2019.
  11. ↑ a b c P. Santos-Sanz, E. Lellouch, S. Fornasier, C. Kiss, A. Pal, TG Müller, E. Vilenius, J. Stansberry, M. Mommert, A. Delsanti, M. Mueller, N . Peixinho, F. Henry, JL Ortiz, A. Thirouin, S. Protopapa, R. Duffard, N. Szalai, T. Lim, C. Ejeta, P. Hartogh, AW Harris, M. Rengel: “TNOs are Cool” : A survey of the trans-Neptunian region. IV. Size / albedo characterization of 15 scattered disk and detached objects observed with Herschel-PACS . In: Astronomy and Astrophysics . 541, no.A92 , May 4, 2012. arxiv : 1202.1481 . bibcode : 2012A & A ... 541A..92S . doi : 10.1051 / 0004-6361 / 201118541 .
  12. ^ G. Tancredi: Physical and dynamical characteristics of icy “dwarf planets” (plutoids) . IAU. April 1, 2010. Retrieved January 29, 2019.
  13. ↑ K. Schindler et al. a .: First Direct Size Measurement of a Detached Object: Results from a Triple Chord Occultation and Far-infrared Photometry of (229762) 2007 UK126 (June 2016)
  14. ↑ G. Benedetti-Rossi et al. a .: Results from the 2014 November 15th Multi-chord Stellar Occultation by the TNO (229762) 2007 UK126 (December 2016, PDF)
  15. ↑ M. Brown : How many dwarf planets are there in the outer solar system? (November 2018)