(28978) Ixion

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Asteroid
(28978) Ixion
Image taken by the Hubble Space Telescope
Image taken by the Hubble Space Telescope
Properties of the orbit ( animation )
Epoch:  April 27, 2019 ( JD 2,458,600.5)
Orbit type Plutino ,
"Distant Object"
Major semi-axis 39.791  AU
eccentricity 0.243
Perihelion - aphelion 30.103 AU - 49.479 AU
Inclination of the orbit plane 19.6 °
Length of the ascending node 71 °
Argument of the periapsis 298.2 °
Time of passage of the perihelion February 28, 2070
Sidereal period 251 a 0.1 M
Mean orbital velocity 4.683 km / s
Physical Properties
Medium diameter
Albedo 0.141 ± 0.011
Rotation period 12.4 ± 0.3 h (0.517 d )
Absolute brightness 3.6 - 3.828 ± 0.039 mag
Spectral class C
B-V = 1.009 ± 0.051
VR = 0.610 ± 0.030
VI = 1.146 ± 0.086
history
Explorer James L. Elliot
Lawrence H. Wasserman
Date of discovery May 22, 2001
Another name 2001 KX 76
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.

(28978) Ixion (former name 2001 KX 76 ) is a large trans-Neptunian object in the Kuiper belt , which is classified as Plutino in terms of orbital dynamics . Because of its size, the asteroid is a dwarf planet candidate .

Discovery and naming

Although the discovery is officially attributed to the Deep Ecliptic Survey by the JPL , Ixion was discovered on May 22, 2001 by James Elliot and Larry Wasserman at the Cerro Tololo Observatory ( Chile ). The discovery was announced on July 1, 2001 together with the TNO 2001 FT 185 , 2001 KW 76 , 2001 KY 76 , 2001 KZ 76 and 2001 KA 77 , the planetoid was given the provisional designation 2001 KX 76 and later the minor planet number 28978 .

On March 28, 2002, the Minor Planet Center announced the name Ixion . Ixion is a king of the Lapiths from Greek mythology.

Like all other Trans-Neptunian objects except Pluto , Ixion has no official or commonly used astronomical symbol . Ixion symbols circulating on the Internet such as B. Ixion symbol proposal 1.pngand Ixion symbol proposal 2.pngare designs by private individuals. An official symbol assignment is not to be expected, since astronomical symbols only play a subordinate role in modern astronomy.

After its discovery, Ixion could be identified on photos taken as part of the Digitized Sky Survey project at the Siding Spring Observatory ( Australia ) up to July 17, 1982, and thus extended its observation period by 19 years so to calculate its orbit more precisely. Since then, the planetoid has been observed through various telescopes such as the Herschel and Spitzer space telescopes as well as earth-based telescopes. In June 2018, there were a total of 174 observations over a period of 36 years. The last observation so far was carried out in June 2018 at the Vegaquattro Observatory ( Piedmont ). (As of February 25, 2019)

properties

Orbit of Ixion - Polar View
Orbit of Ixion - Ecliptic View
Orbit of Ixion (green) compared to the
orbit of Neptune and others.

Orbit

Ixion orbits the Sun in 251.01 years in an elliptical orbit between 30.10  AU and 49.48 AU from its center. The orbital eccentricity is 0.243, the orbit is 19.58 ° inclined to the ecliptic . Currently, the planetoid is 39.31 AU from the sun. He will next pass perihelion in 2070, so the last perihelion should have occurred in 1819. Ixion and Pluto follow similar but differently oriented orbits; while Ixion's perihelion is below the ecliptic, Pluto's perihelion is above it. Atypical for resonant KBOs like Orcus , Ixion approaches Pluto with less than 20 degrees of angular distance.

Both the Marc Buie ( DES ) and the Minor Planet Center classify Ixion as Plutino , the latter also generally lists it as a “Distant Object”.

Size and rotation

Ixion's diameter was initially estimated to be about 1,300 miles. This made it the first object in the Kuiper Belt that was believed to be larger than Ceres , the largest object in the Main Belt and the former record holder among the planetoids. In 2013, observations with the Herschel and Spitzer space telescopes showed that Ixion has a fairly bright surface ( albedo about 0.14), so that the diameter of 617 km must be estimated correspondingly smaller. Assuming a diameter of 617 km, this results in a total area of ​​around 1,196,000 km². The apparent magnitude of Ixion is 19.85  m ; the mean surface temperature is estimated at 44 K (−229 ° C) based on the distance from the sun  .

Mike Brown believes that Ixion is most likely a dwarf planet as it is believed to be in hydrostatic equilibrium based on its estimated size and mass . The analysis of the very flat light curve suggests that Ixion should be almost spherical ( Maclaurin ellipsoid ). Gonzalo Tancredi accepted Ixion as a dwarf planet in 2010, but did not propose to the IAU that it be officially recognized as such.

Based on light curve observations in 2010, Ixion rotates once around its axis every 12 hours and 24 minutes. From this it follows that in one Ixion year it performs 177447.3 self- rotations (“days”). Ixion shows some regular changes in brightness, which are attributed to the rotation behavior.

Size comparison of some large TNOs
Provisions of the diameter for Ixion
year Dimensions km source
2002 1055.0 + 0165.0- 0165.0 Altenhoff et al. a.
2003 <804.0 Altenhoff et al. a.
2005 <822.0 Grundy et al. a.
2005 475.0 ± 75.0 Stansberry et al. a.
2007 480.0 + 0152.0- 0136.0 Cruikshank et al. a.
2008 480.0 Tancredi
2008 > 350.0 + 050.0- 050.0
> 650.0 + 0260.0- 0220.0 		Stansberry et al. a.
2010 650.0 Tancredi
2013 800.80 LightCurve DataBase
2013 617.0 + 019.0- 020.0 Lellouch u. a.
2013 549.0 Mommert et al. a.
2018 674.0 Brown
The most precise determination is marked in bold .

surface

Ixion's surface is reddish in color in visible light (somewhat redder than Quaoar ) and has a relatively high albedo of 0.141 ± 0.011 for objects of this size. In the near infrared the spectrum shows no abnormalities, absorption lines for water ice are completely absent - in contrast to Varuna . The most likely composition consists of amorphous carbon, tholines, and very little water ice.

Investigations into possible cometary activity or atmosphere with the Very Large Telescope 2007 produced a negative result; however, it is possible that, much like Pluto , Ixion could develop a coma or temporary atmosphere near its perihelion, which it will reach in 2070.

Possible exploration by spacecraft

According to a 2012 study, Ixion and Huya are the most suitable of seven possible TNOs for an orbital mission that could start with an Atlas V 551 or Delta IV HLV and include gravity assist on the planet Jupiter . A mission launched on November 11, 2039 would reach Ixion in 2056 after 17 years of flight time. A more recent study from 2018 envisages various options with starts between 2025 and 2040, which could also include possible fly-bys of Saturn , Uranus and Neptune .

See also

Web links

Commons : (28978) Ixion  - Collection of images, videos and audio files

Individual evidence

  1. ^ A b Marc W. Buie : Orbit Fit and Astrometric record for 28978 . SwRI (Space Science Department). Retrieved February 25, 2019.
  2. ↑ a b MPC : MPEC 2010-S44: Distant Minor Planets (2010 OCT.11.0 TT) . IAU . September 25, 2010. Retrieved February 25, 2019.
  3. ↑ a b c d e f E. Lellouch u. a .: “TNOs are Cool”: A survey of the trans-Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations (PDF) . In: Astronomy and Astrophysics . 557, No. A60, June 10, 2013, p. 19. bibcode : 2013A & A ... 557A..60L . doi : 10.1051 / 0004-6361 / 201322047 .
  4. ↑ a b c (28978) Ixion at the IAU Minor Planet Center (English) Retrieved February 25, 2019.
  5. ↑ v ≈ π * a / period (1 + sqrt (1-e²))
  6. ↑ a b c M. Galiazzo u. a .: Photometry of Centaurs and trans-Neptunian objects: 2060 Chiron (1977 UB), 10199 Chariklo (1997 CU26), 38628 Huya (2000 EB173), 28978 Ixion (2001 KX76), and 90482 Orcus (2004 DW) (PDF) . In: Astrophysics and Space Science . 361, No. 7, June 3, 2016, p. 15. arxiv : 1605.08251 . bibcode : 2016Ap & SS.361..212G . doi : 10.1007 / s10509-016-2801-5 .
  7. ↑ a b LCDB Data for (28978) Ixion . MinorPlanetInfo. May 2013. Retrieved February 25, 2019.
  8. ↑ a b c O. Hainaut u. a .: Colors of minor bodies in the outer solar system. II. A statistical analysis revisited (PDF) . In: Astronomy and Astrophysics . 546, No. A115, September 10, 2012, p. 20. arxiv : 1209.1896 . bibcode : 2012A & A ... 546A.115H . doi : 10.1051 / 0004-6361 / 201219566 .
  9. ↑ a b (28978) Ixion in the Small-Body Database of the Jet Propulsion Laboratory (English). Retrieved February 25, 2019. Template: JPL Small-Body Database Browser / Maintenance / Alt
  10. ↑ MPC : MPEC 2001-N01: 2001 FT185, 2001 KW76, 2001 KX76, 2001 KY76, 2001 KZ76, 2001 KA77 . IAU . July 1, 2001. Retrieved February 25, 2019.
  11. ↑ MPC : MPC / MPO / MPS Archive . IAU . Retrieved February 25, 2019.
  12. ^ Richard Stenger: New object deemed largest minor planet . CNN . January 24, 2001. Retrieved February 25, 2019.
  13. ↑ AstDyS-2: (28978) Ixion . Universita di Pisa. Retrieved February 25, 2019.
  14. ↑ a b Gonzalo Tancredi: Physical and dynamical characteristics of icy “dwarf planets” (plutoids) (PDF) . In: International Astronomical Union (Ed.): Icy Bodies of the Solar System: Proceedings IAU Symposium No. 263, 2009 . 2010. doi : 10.1017 / S1743921310001717 . Retrieved February 25, 2019.
  15. ↑ a b H. Boehnhardt u. a .: Surface characterization of 28978 Ixion (2001 KX 76 ) . In: Astronomy and Astrophysics . 415, No. 2, February 11, 2004, pp. L21-L25. bibcode : 2004A & A ... 415L..21B . doi : 10.1051 / 0004-6361: 20040005 .
  16. ↑ SpaceRef: Beyond Pluto: Max-Planck radioastronomers measure the sizes of distant minor planets . Max Planck Institute . October 7, 2002. Retrieved February 25, 2019.
  17. ↑ W. Altenhoff u. a .: Size estimates of some optically bright KBOs (PDF) . In: Astronomy and Astrophysics . 415, Nov. 10, 2003, pp. 771-775. bibcode : 2004A & A ... 415..771A . doi : 10.1051 / 0004-6361: 20035603 .
  18. ↑ W. Grundy et al. a .: Various Albedos of Small Trans-Neptunian Objects (PDF) . In: Icarus . 176, No. 1, February 10, 2005, pp. 184-191. arxiv : astro-ph / 0502229 . bibcode : 2005Icar..176..184G . doi : 10.1016 / j.icarus.2005.01.007 .
  19. ↑ J. Stansberry et al. a .: Albedos, diameters (and a density) of Kuiper belt and Centaur objects . In: American Astronomical Society DPS meeting # 37 . 37, No. 737, August 2005. bibcode : 2005DPS .... 37.5205S .
  20. ↑ D. Cruikshank et al. a .: Physical Properties of Transneptunian Objects (PDF) . In: University of Arizona Press: Protostars and Planets . 951, 2006, pp. 879-893. bibcode : 2007prpl.conf..879C .
  21. ^ Gonzalo Tancredi, Sofía Favre: DPPH List . In: Dwarf Planets and Plutoid Headquarters, from Which are the dwarfs in the solar system? . August. Retrieved February 25, 2019.
  22. ↑ J. Stansberry et al. a .: Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope (PDF) . In: University of Arizona Press . 592, No. 161-179, February 20, 2007. arxiv : astro-ph / 0702538 . bibcode : 2008ssbn.book..161S .
  23. ↑ M. Mommert et al. a .: Remnant planetesimals and their collisional fragments: Physical characterization from thermal-infrared observations . September 23, 2013. Accessed February 25, 2019.
  24. ↑ Mike Brown : How many dwarf planets are there in the outer solar system? . CalTech . November 12, 2018. Retrieved February 25, 2019.
  25. ↑ M. Licandro et al. a .: Infrared spectroscopy of the largest known trans-Neptunian object 2001 KX76 (PDF) . In: Astronomy and Astrophysics . 388, No. 1, May 28, 2002, pp. L9-L12. arxiv : astro-ph / 0204104 . bibcode : 2002A & A ... 388L ... 9L . doi : 10.1051 / 0004-6361: 20020533 .
  26. ^ O. Lorin, P. Rousselot: Search for cometary activity in three Centaurs (60558) Echeclus, 2000 FZ53 and 2000 GM137 and two trans-Neptunian objects (29981) 1999 TD10 and (28978) Ixion . In: Monthly Notices of the Royal Astronomical Society . 376, No. 2, April 2007, pp. 881-889. bibcode : 2007MNRAS.376..881L . doi : 10.1111 / j.1365-2966.2007.11487.x .
  27. ↑ A. Gleaves et al. a .: A Survey of Mission Opportunities to Trans-Neptunian Objects - Part II, Orbital Capture. AIAA / AAS Astrodynamics Specialist Conference . In: Earth and Planetary Astrophysics . August 13, 2012. doi : 10.2514 / 6.2012-5066 .
  28. ↑ M. Zangari et al. a .: Return to the Kuiper Belt: launch opportunities from 2025 to 2040 (PDF) . In: Earth and Planetary Astrophysics . October 17, 2018. arxiv : 1810.07811 .