Extreme trans-Neptunian object

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
File:Distant object orbits + Planet Nine.png
The orbits of Sedna, 2012 VP113, Leleākūhonua, and other very distant objects along with the predicted orbit of Planet Nine[A]

An extreme trans-Neptunian object (ETNO) is a trans-Neptunian object orbiting the Sun well beyond Neptune (30 AU) in the outermost region of the Solar System. An ETNO has a large semi-major axis of at least 150–250 AU.[1][2] The orbits of ETNOs are much less affected by the known giant planets than all other known trans-Neptunian objects. They may, however, be influenced by gravitational interactions with a hypothetical Planet Nine, shepherding these objects into similar types of orbits.[1] The known ETNOs exhibit a highly statistically significant asymmetry between the distributions of object pairs with small ascending and descending nodal distances that might be indicative of a response to external perturbations.[3][4]

ETNOs can be divided into three different subgroups. The scattered ETNOs (or extreme scattered disc objects, ESDOs) have perihelia around 38–45 AU and an exceptionally high eccentricity of more than 0.85. As with the regular scattered disc objects, they were likely formed as result of gravitational scattering by Neptune and still interact with the giant planets. The detached ETNOs (or extreme detached disc objects, EDDOs), with perihelia approximately between 40–45 and 50–60 AU, are less affected by Neptune than the scattered ETNOs, but are still relatively close to Neptune. The sednoid or inner Oort cloud objects, with perihelia beyond 50–60 AU, are too far from Neptune to be strongly influenced by it.[1]

Sednoids

[edit | edit source]
See also: Sednoids

Among the extreme trans-Neptunian objects are the sednoids, four objects with an outstandingly high perihelion: Sedna, 2012 VP113, Leleākūhonua, and 2023 KQ14. Sedna and 2012 VP113 are distant detached objects with perihelia greater than 70 AU. Their high perihelia keep them at a sufficient distance to avoid significant gravitational perturbations from Neptune. Previous explanations for the high perihelion of Sedna include a close encounter with an unknown planet on a distant orbit and a distant encounter with a random star or a member of the Sun's birth cluster that passed near the Solar System.[5][6][7]

Most distant objects from the Sun

[edit | edit source]
File:Extreme transneptunian object eccentricity vs perihelion.png
The chart above plots trans-Neptunian objects with a perihelion beyond Neptune (30 AU). While regular TNOs are located in the bottom left of the plot, an ETNO has a semi-major axis greater than 150–250 AU. They can be grouped by their perihelia into three distinct populations:[1]   scattered ETNOs or ESDOs (38–45 AU)
  detached ETNOs or EDDOs (40–45 to 50–60 AU)
  Sednoids or inner Oort cloud objects (beyond 50–60 AU)
Main article: List of Solar System objects most distant from the Sun

Notable discoveries

[edit | edit source]

Trujillo and Sheppard discoveries

[edit | edit source]

Extreme trans-Neptunian objects discovered by astronomers Chad Trujillo and Scott S. Sheppard include:

  • 2013 FT28, Longitude of perihelion aligned with Planet Nine, but well within the proposed orbit of Planet Nine, where computer modeling suggests it would be safe from gravitational kicks.[8]
  • 2014 SR349, appears to be anti-aligned with Planet Nine.[8]
  • 2014 FE72, an object with an orbit so extreme that it reaches about 4000 AU from the Sun in a massively-elongated ellipse – at this distance its orbit is influenced by the galactic tide and other stars.[9][10][11][12]

Outer Solar System Origins Survey

[edit | edit source]

The Outer Solar System Origins Survey has discovered more extreme trans-Neptunian objects, including:[13]

  • 2013 SY99, which has a lower inclination than many of the objects, and which was discussed by Michele Bannister at a March 2016 lecture hosted by the SETI Institute and later at an October 2016 AAS conference.[14][15]
  • 2015 KG163, which has an orientation similar to 2013 FT28 but has a larger semi-major axis that may result in its orbit crossing Planet Nine's.
  • 2015 RX245, which fits with the other anti-aligned objects.
  • 2015 GT50, which is in neither the anti-aligned nor the aligned groups; instead, its orbit's orientation is at a right angle to that of the proposed Planet Nine. Its argument of perihelion is also outside the cluster of arguments of perihelion.

Since early 2016, ten more extreme trans-Neptunian objects have been discovered with orbits that have a perihelion greater than 30 AU and a semi-major axis greater than 250 AU bringing the total to sixteen (see table below for a complete list). Most TNOs have perihelia significantly beyond Neptune, which orbits 30 AU from the Sun.[16][17] Generally, TNOs with perihelia smaller than 36 AU experience strong encounters with Neptune.[18][19] Most of the ETNOs are relatively small, but currently relatively bright because they are near their closest distance to the Sun in their elliptical orbits. These are also included in the orbital diagrams and tables below.

[edit | edit source]

Malena Rice and Gregory Laughlin applied a targeted shift-stacking search algorithm to analyze data from TESS sectors 18 and 19 looking for candidate outer Solar System objects.[20] Their search recovered known ETNOs like Sedna and produced 17 new outer Solar System body candidates located at geocentric distances in the range 80–200 AU, that need follow-up observations with ground-based telescope resources for confirmation. Early results from a survey with WHT aimed at recovering these distant TNO candidates have failed to confirm two of them.[21][22]

List

[edit | edit source]
The extreme trans-Neptunian object orbits
Orbits of extreme trans-Neptunian objects and Planet Nine
Close up view of 13 TNO current positions
Close up of extreme trans-Neptunian objects' and planets' orbits
6 original and 10 additional TNO object orbits with current positions near their perihelion in purple

Extreme trans-Neptunian objects with perihelia greater than 30 AU and semi-major axes greater than 250 AU[23][24][25]
Object Barycentric Orbit (JD 2459600.5)[B] Orbital plane Body
Stability
[28] 		Orbital
period
(years) 		Semimajor
axis
(AU) 		Perihelion
(AU) 		Aphelion
(AU) 		Current
distance
from
Sun
(AU) 		Eccent. Argum.
peri
ω (°) 		inclin.
i (°) 		Longitude of Hv Current
mag. 		Diameter
(km)
Ascending
node
☊ or Ω (°) 		Perihelion
ϖ=ω+Ω (°)
Sedna Stable 11,400 485 76.3 893 84.5 0.84 311.3 11.9 144.2 95.6 1.3 20.7 1,000
Alicanto Stable 5,900 327 47.3 608 48.1 0.86 326.7 25.6 66.0 32.7 6.5 23.5 200
2007 TG422 Unstable 11,260 502 35.6 969 38.5 0.93 285.6 18.6 112.9 38.4 6.5 22.5 200
Leleākūhonua Stable 35,300 1,090 65.2 2,110 78.0 0.94 117.8 11.7 300.8 58.5 5.5 24.6 220
2010 GB174 Stable 6,600 342 48.6 636 73.1 0.86 347.1 21.6 130.9 118.0 6.5 25.2 200
2012 VP113 Stable 4,300 261 80.4 443 84.0 0.69 293.6 24.1 90.7 24.3 4.0 23.3 600
2013 FL28 ? 6,780 358 32.2 684 33.4 0.91 225.1 15.8 294.4 159.5 (*) 8.0 23.4 100
2013 FT28 Metastable 5,050 305 43.4 566 55.2 0.86 40.8 17.4 217.7 258.5 (*) 6.7 24.2 200
2013 RF98 Unstable 6,900 370 36.1 705 37.6 0.90 311.6 29.6 67.6 19.2 8.7 24.6 70
2013 RA109 ? 9,950 463 46.0 880 47.4 0.90 262.9 12.4 104.8 7.6 6.1 23.1 200
2013 SY99 Metastable 19,800 733 50.0 1,420 57.9 0.93 32.2 4.2 29.5 61.7 6.7 24.5 250
2013 SL102 Unstable 5,590 326 38.1 614 39.3 0.88 265.4 6.5 94.6 0.0 (*) 7.0 23.2 140
2014 FE72 Unstable 92,400 2,040 36.1 4,050 64.0 0.98 133.9 20.6 336.8 110.7 6.2 24.3 200
2014 SX403 ? 7,180 370 35.5 710 45.1 0.90 174.7 42.9 149.2 323.9 (*) 7.1 23.8 130
2014 SR349 Stable 5,160 312 47.7 576 54.8 0.85 340.8 18.0 34.9 15.6 6.7 24.2 200
2014 TU115 ? 6,140 335 35.0 636 35.3 0.90 225.3 23.5 192.3 57.7 7.9 23.5 90
2014 WB556 Metastable? 4,900 288 42.7 534 46.6 0.85 235.3 24.2 114.7 350.0 (*) 7.3 24.2 150
2015 BP519[29] ? 9,500 433 35.2 831 51.4 0.92 348.2 54.1 135.0 123.3 (*) 4.5 21.7 550[30]
2015 DY248 ? 5,400 309 34.0 585 34.4 0.89 244.6 12.9 273.1 157.7 (*) 8.3 23.9 100
2015 DM319
(uo5m93)[31]		 Unstable? 4,620 278 39.5 516 41.7 0.86 43.4 6.8 166.0 209.4 (*) 8.7 25.0 80?
2015 GT50 Unstable 5,510 314 38.5 589 42.9 0.88 129.3 8.8 46.1 175.4 (*) 8.5 24.9 80
2015 KG163 Unstable 22,840 805 40.5 1,570 40.5 0.95 32.3 14.0 219.1 251.4 (*) 8.2 24.4 100
2015 RX245 Metastable 8,920 421 45.7 796 59.9 0.89 64.8 12.1 8.6 73.4 6.2 24.1 250
2016 SA59 ? 3,830 250 39.1 451 42.3 0.84 200.3 21.5 174.7 15.0 7.8 24.2 90
2016 SD106 ? 6,550 350 42.7 658 44.5 0.88 162.9 4.8 219.4 22.3 6.7 23.4 160
2017 OF201 ? 24,200 837 44.9 1,629 88.5 0.95 337.7 16.2 328.6 306.3 (*) 3.5 23.0 800
2018 VM35 Stable 4,500 252 45.0 459 54.8 0.82 302.9 8.5 192.4 135.3 (*) 7.7 25.2 140
2019 EU5 ? 42,600 1,220 46.8 2,400 81.1 0.96 109.2 18.2 109.2 218.4 (*) 6.4 25.6 180
2020 MQ53 ? 21,395 770 55.6 1,486 — 0.93 18.6 73.4 287.1 305.7 (*) 8.6 70
2021 DK18 ? 21,400 770 44.4 1,500 66.3 0.94 234.8 15.4 322.3 197.0 (*) 6.8 25.1 180
2021 RR205 ? 31,200 992 55.5 1,930 60.0 0.94 208.6 7.6 108.3 316.9 (*) 6.8 24.6 180
Ideal elements
under hypothesis		 — >250 >30 — — >0.5 — 10~30 — 2~120 — — —
Hypothesized
Planet Nine		 8,000–22,000 400–800 ~200 ~1,000 ~1,000? 0.2–0.5 ~150 15–25 91±15 241±15 >22.5 ~40,000
  • (*) longitude of perihelion, ϖ, outside expected range;
  •    are the objects included in the original study by Trujillo and Sheppard (2014).[32]
  •    has been added in the 2016 study by Brown and Batygin.[18][33][34]
  • All other objects have been announced later.

The most extreme case is that of 2015 BP519, nicknamed Caju, which has both the highest inclination[35] and the farthest nodal distance; these properties make it a probable outlier within this population.[2]

Notes

[edit | edit source]
  1. ^ The three sednoids (pink) along with the red-colored extreme trans-Neptunian object (ETNO) orbits are suspected to be aligned with the hypothetical Planet Nine while the blue-colored ETNO orbits are anti-aligned. The highly elongated orbits colored brown include centaurs and damocloids with large aphelion distances over 200 AU.
  2. ^ Given the orbital eccentricity of these objects, different epochs can generate quite different heliocentric unperturbed two-body best-fit solutions to the semi-major axis and orbital period. For objects at such high eccentricity, the Sun's barycenter is more stable than heliocentric values. Barycentric values better account for the changing position of Jupiter over Jupiter's 12 year orbit. As an example, 2007 TG422 has an epoch 2012 heliocentric period of ~13,500 years,[26] yet an epoch 2020 heliocentric period of ~10,800 years.[27] The barycentric solution is a much more stable ~11,300 years.

References

[edit | edit source]
  1. ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  2. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  3. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  5. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  7. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  8. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  11. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  12. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  13. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  15. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  16. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  17. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  18. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  19. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  20. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  21. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  22. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  23. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). (Solution using the Solar System Barycenter and barycentric coordinates. (Type the target body's name, then select Ephemeris Type:Elements and Center:@0) In the second pane "PR=" can be found, which gives the orbital period in days (For Sedna as an example, the value 4.16E+06 is displayed, which is ~11400 Julian years).
  24. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  25. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  26. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  27. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  28. ^ Relative to hypothetical Planet Nine, Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  29. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  30. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  31. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  32. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  33. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  34. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).Open access icon
  35. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
[edit | edit source]
Retrieved from "http://70.231.62.181/index.php?title=Extreme_trans-Neptunian_object&oldid=23159163"