Plutino

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In astronomy, the plutinos are a dynamical group of trans-Neptunian objects that orbit in 2:3 mean-motion resonance with Neptune. This means that for every two orbits a plutino makes, Neptune orbits three times. The dwarf planet Pluto is the largest member as well as the namesake of this group. The next largest members are Orcus, (208996) 2003 AZ84 , and Ixion. Plutinos are named after mythological creatures associated with the underworld.

Contents

Plutinos form the inner part of the Kuiper belt and represent about a quarter of the known Kuiper belt objects. They are also the most populous known class of resonant trans-Neptunian objects (also see adjunct box with hierarchical listing). The first plutino after Pluto itself, (385185) 1993 RO, was discovered on September 16, 1993.

Orbits

Some of the first known plutinos compared in size, albedo and colour ThePlutinos Size Albedo Color2.svg
Some of the first known plutinos compared in size, albedo and colour

Origin

It is thought that the objects that are currently in mean orbital resonances with Neptune initially followed a variety of independent heliocentric paths. As Neptune migrated outward early in the Solar System's history (see origins of the Kuiper belt), the bodies it approached would have been scattered; during this process, some of them would have been captured into resonances. [1] The 3:2 resonance is a low-order resonance and is thus the strongest and most stable among all resonances. [2] This is the primary reason it has a larger population than the other Neptunian resonances encountered in the Kuiper Belt. The cloud of low-inclination bodies beyond 40 AU is the cubewano family, while bodies with higher eccentricities (0.05 to 0.34) and semimajor axes close to the 3:2 Neptune resonance are primarily plutinos. [3]

Orbital characteristics

The distribution of Plutinos, and relative sizes, drawn 1 million times larger. Plutino distributions and sizes.png
The distribution of Plutinos, and relative sizes, drawn 1 million times larger.

While the majority of plutinos have relatively low orbital inclinations, a significant fraction of these objects follow orbits similar to that of Pluto, with inclinations in the 10–25° range and eccentricities around 0.2–0.25; such orbits result in many of these objects having perihelia close to or even inside Neptune's orbit, while simultaneously having aphelia that bring them close to the main Kuiper belt's outer edge (where objects in a 1:2 resonance with Neptune, the Twotinos, are found).

The orbital periods of plutinos cluster around 247.3 years (1.5 × Neptune's orbital period), varying by at most a few years from this value.

Unusual plutinos include:

See also the comparison with the distribution of the cubewanos.

Long-term stability

Pluto's influence on the other plutinos has historically been neglected due to its relatively small mass. However, the resonance width (the range of semi-axes compatible with the resonance) is very narrow and only a few times larger than Pluto's Hill sphere (gravitational influence). Consequently, depending on the original eccentricity, some plutinos will eventually be driven out of the resonance by interactions with Pluto. [4] Numerical simulations suggest that the orbits of plutinos with an eccentricity 10%–30% smaller or larger than that of Pluto are not stable over Ga timescales. [5]

Orbital diagrams

Brightest objects

The plutinos brighter than HV=6 include:

Object a
(AU)
q
(AU)
i
(°)
H Diameter
(km)
Mass
(1020 kg)
Albedo V−R Discovery
year
DiscovererRefs
134340 Pluto 39.329.717.1−0.723221300.49–0.661930 Clyde Tombaugh JPL
90482 Orcus 39.230.320.62.31±0.03917±256.32±0.050.28±0.060.372004M. Brown,
C. Trujillo,
D. Rabinowitz
JPL
(208996) 2003 AZ84 39.432.313.63.74±0.08727.0+61.9
−66.5
30.107+0.023
−0.016
0.38±0.042003M. Brown,
C. Trujillo
JPL
28978 Ixion 39.730.119.63.828±0.039617+19
−20
30.141±0.0110.612001 Deep Ecliptic Survey JPL
2017 OF69 39.531.313.64.091±0.12380–680 ? ? ?2017 D. J. Tholen,
S. S. Sheppard,
C. Trujillo
JPL
(84922) 2003 VS2 39.336.414.84.1±0.38523.0+35.1
−34.4
1.50.147+0.063
−0.043
0.59±0.022003 NEAT JPL
(455502) 2003 UZ413 39.230.412.04.38±0.056002 ?0.46±0.062001M. Brown,
C. Trujillo,
D. Rabinowitz
JPL
2014 JR80 39.536.015.44.9240–670 ? ? ?2014 Pan-STARRS JPL
2014 JP80 39.536.719.44.9240–670 ? ? ?2014 Pan-STARRS JPL
38628 Huya 39.428.515.55.04±0.03406±160.50.083±0.0040.57±0.092000Ignacio Ferrin JPL
(469987) 2006 HJ123 39.327.412.05.32±0.66283.1+142.3
−110.8
0.0120.136+0.308
−0.089
2006 Marc W. Buie JPL
2002 XV93 39.334.513.35.42±0.46549.2+21.7
−23.0
1.70.040+0.020
−0.015
0.37±0.022001M.W.Buie JPL
(469372) 2001 QF298 39.334.922.45.43±0.07408.2+40.2
−44.9
0.70.071+0.020
−0.014
0.39±0.062001Marc W. Buie JPL
47171 Lempo 39.330.68.45.41±0.10393.1+25.2
−26.8

(triple)
0.1275±0.00060.079+0.013
−0.011
0.70±0.031999E. P. Rubenstein,
L.-G. Strolger
JPL
(307463) 2002 VU130 39.331.214.05.47±0.83252.9+33.6
−31.3
0.160.179+0.202
−0.103
2002 Marc W. Buie JPL
(84719) 2002 VR128 39.328.914.05.58±0.37448.5+42.1
−43.2
10.052+0.027
−0.018
0.60±0.022002 NEAT JPL
(55638) 2002 VE95 39.430.416.35.70±0.06249.8+13.5
−13.1
0.150.149+0.019
−0.016
0.72±0.052002 NEAT JPL

Related Research Articles

Classical Kuiper belt object Kuiper belt object, not controlled by an orbital resonance with Neptune

A classical Kuiper belt object, also called a cubewano ( "QB1-o"), is a low-eccentricity Kuiper belt object (KBO) that orbits beyond Neptune and is not controlled by an orbital resonance with Neptune. Cubewanos have orbits with semi-major axes in the 40–50 AU range and, unlike Pluto, do not cross Neptune's orbit. That is, they have low-eccentricity and sometimes low-inclination orbits like the classical planets.

Kuiper belt Area of the Solar System beyond the planets, comprising small bodies

The Kuiper belt is a circumstellar disc in the outer Solar System, extending from the orbit of Neptune at 30 astronomical units (AU) to approximately 50 AU from the Sun. It is similar to the asteroid belt, but is far larger—20 times as wide and 20–200 times as massive. Like the asteroid belt, it consists mainly of small bodies or remnants from when the Solar System formed. While many asteroids are composed primarily of rock and metal, most Kuiper belt objects are composed largely of frozen volatiles, such as methane, ammonia, and water. The Kuiper belt is home to most of the objects that astronomers generally accept as dwarf planets: Orcus, Pluto, Haumea, Quaoar, and Makemake. Some of the Solar System's moons, such as Neptune's Triton and Saturn's Phoebe, may have originated in the region.

Trans-Neptunian object Solar system objects beyond Neptune

A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has a semi-major axis of 30.1 astronomical units (AU).

90482 Orcus Trans-Neptunian object and dwarf planet

Orcus is a trans-Neptunian dwarf planet with a large moon, Vanth. It has a diameter of 910 km (570 mi). The surface of Orcus is relatively bright with albedo reaching 23 percent, neutral in color and rich in water ice. The ice is predominantly in crystalline form, which may be related to past cryovolcanic activity. Other compounds like methane or ammonia may also be present on its surface. Orcus was discovered by American astronomers Michael Brown, Chad Trujillo, and David Rabinowitz on 17 February 2004.

In astronomy, a resonant trans-Neptunian object is a trans-Neptunian object (TNO) in mean-motion orbital resonance with Neptune. The orbital periods of the resonant objects are in a simple integer relations with the period of Neptune, e.g. 1:2, 2:3, etc. Resonant TNOs can be either part of the main Kuiper belt population, or the more distant scattered disc population.

Scattered disc Collection of bodies in the extreme Solar System

The scattered disc (or scattered disk) is a distant circumstellar disc in the Solar System that is sparsely populated by icy small solar system bodies, which are a subset of the broader family of trans-Neptunian objects. The scattered-disc objects (SDOs) have orbital eccentricities ranging as high as 0.8, inclinations as high as 40°, and perihelia greater than 30 astronomical units (4.5×109 km; 2.8×109 mi). These extreme orbits are thought to be the result of gravitational "scattering" by the gas giants, and the objects continue to be subject to perturbation by the planet Neptune.

<span class="nowrap">(208996) 2003 AZ<sub>84</sub></span> Plutino

(208996) 2003 AZ84 is a trans-Neptunian object with a possible moon from the outer regions of the Solar System. It is approximately 940 kilometers across its longest axis, as it has an elongated shape. It belongs to the plutinos – a group of minor planets named after its largest member Pluto – as it orbits in a 2:3 resonance with Neptune in the Kuiper belt. It is the third-largest known plutino, after Pluto and Orcus. It was discovered on 13 January 2003, by American astronomers Chad Trujillo and Michael Brown during the NEAT survey using the Samuel Oschin telescope at Palomar Observatory.

<span class="nowrap">(15875) 1996 TP<sub>66</sub></span>

(15875) 1996 TP66, provisional designation 1996 TP66, is a resonant trans-Neptunian object of the plutino population, located in the outermost region of the Solar System, approximately 154 kilometers (96 miles) in diameter. It was discovered on 11 October 1996, by astronomers Jane Luu, David C. Jewitt and Chad Trujillo at the Mauna Kea Observatories, Hawaii, in the United States. The very reddish RR-type with a highly eccentric orbit has been near its perihelion around the time of its discovery. This minor planet was numbered in 2000 and has since not been named. It is probably not a dwarf planet candidate.

(119951) 2002 KX<sub>14</sub>

(119951) 2002 KX14, also written as 2002 KX14, is a medium sized trans-Neptunian object (TNO) residing within the Kuiper belt. It was discovered on 17 May 2002 by Michael E. Brown and Chad Trujillo.

(35671) 1998 SN165, prov. designation: 1998 SN165, is a trans-Neptunian object from the Kuiper belt located in the outermost region of the Solar System. It was discovered on 23 September 1998, by American astronomer Arianna Gleason at the Kitt Peak National Observatory near Tucson, Arizona. The cold classical Kuiper belt object is a dwarf planet candidate, as it measures approximately 400 kilometers (250 miles) in diameter. It has a grey-blue color (BB) and a rotation period of 8.8 hours. As of 2021, it has not been named.

Detached object Dynamical class of minor planets

Detached objects are a dynamical class of minor planets in the outer reaches of the Solar System and belong to the broader family of trans-Neptunian objects (TNOs). These objects have orbits whose points of closest approach to the Sun (perihelion) are sufficiently distant from the gravitational influence of Neptune that they are only moderately affected by Neptune and the other known planets: This makes them appear to be "detached" from the rest of the Solar System, except for their attraction to the Sun.

(55638) 2002 VE95, prov. designation: 2002 VE95, is a trans-Neptunian object from the outermost region of the Solar System. It was discovered on 14 November 2002, by astronomers with the Near-Earth Asteroid Tracking program at the Palomar Observatory in California, United States. This resonant trans-Neptunian object is a member of the plutino population, locked in a 2:3 resonance with Neptune. The object is likely of primordial origin with a heterogeneous surface and a notably reddish color (RR) attributed to the presence of methanol and tholins. It has a poorly defined rotation period of 6.8 hours and measures approximately 250 kilometers (160 miles) in diameter, too small to be a dwarf planet candidate. As of 2021, it has not yet been named.

2014 FZ71 is a trans-Neptunian object, a scattered disc classified as a scattered and detached object, located in the outermost region of the Solar System. It was first observed on 24 March 2014, by a team led by American astronomer Scott Sheppard at the Cerro Tololo Inter-American Observatory in Chile. With its perihelion of almost 56 AU, it belongs to a small and poorly understood group of very distant objects with moderate eccentricities. The object is not a dwarf planet candidate as it only measures approximately 150 kilometers (93 miles) in diameter.

2014 FC72 is a trans-Neptunian object, classified as a scattered and detached object, located in the outermost region of the Solar System. It was first observed on 24 March 2014 by astronomers with the Pan-STARRS survey at Haleakala Observatory, Hawaii, United States. With its perihelion distant from Neptune, it belongs to a small and poorly understood group of objects with moderate eccentricities. It is estimated to measure 500 kilometers (300 miles) in diameter, assuming a low albedo.

2015 FJ345 is a trans-Neptunian object and detached object, located in the scattered disc, the outermost region of the Solar System. It was first observed on 17 March 2015, by a team led by American astronomer Scott Sheppard at the Mauna Kea Observatories, Hawaii, United States. With its perihelion of almost 51 AU, it belongs to a small and poorly understood group of very distant objects with moderate eccentricities. The object is not a dwarf planet candidate as it only measures approximately 120 kilometers (75 miles) in diameter.

2015 KQ174 is a trans-Neptunian object, both considered a scattered and detached object, located in the outermost region of the Solar System. The object with a moderately inclined and eccentric orbit measures approximately 154 kilometers (96 miles) in diameter. It was first observed on 24 May 2015, by astronomers at the Mauna Kea Observatories in Hawaii, United States.

<span class="nowrap">2013 FQ<sub>28</sub></span>

2013 FQ28 is a trans-Neptunian object, both considered a scattered and detached object, located in the outermost region of the Solar System. It was first observed on 17 March 2013, by a team of astronomers at the Cerro Tololo Inter-American Observatory in Chile. It orbits the Sun in a moderate inclined, moderate-eccentricity orbit. The weak dwarf planet candidate measures approximately 260 kilometers (160 miles) in diameter.

The hypothetical Planet Nine would modify the orbits of extreme trans-Neptunian objects via a combination of effects. On very long timescales exchanges of angular momentum with Planet Nine cause the perihelia of anti-aligned objects to rise until their precession reverses direction, maintaining their anti-alignment, and later fall, returning them to their original orbits. On shorter timescales mean-motion resonances with Planet Nine provides phase protection, which stabilizes their orbits by slightly altering the objects' semi-major axes, keeping their orbits synchronized with Planet Nine's and preventing close approaches. The inclination of Planet Nine's orbit weakens this protection, resulting in a chaotic variation of semi-major axes as objects hop between resonances. The orbital poles of the objects circle that of the Solar System's Laplace plane, which at large semi-major axes is warped toward the plane of Planet Nine's orbit, causing their poles to be clustered toward one side.

References

  1. Malhotra, Renu (1995). "The Origin of Pluto's Orbit: Implications for the Solar System Beyond Neptune". Astronomical Journal. 110: 420. arXiv: astro-ph/9504036 . Bibcode:1995AJ....110..420M. doi:10.1086/117532. S2CID   10622344.
  2. Almeida, A.J.C; Peixinho, N.; Correia, A.C.M. (December 2009). "Neptune Trojans & Plutinos: Colors, sizes, dynamics, & their possible collisions". Astronomy & Astrophysics. 508 (2): 1021–1030. arXiv: 0910.0865 . doi:10.1051/0004-6361/200911943. S2CID   53772214 . Retrieved 2019-07-20.
  3. Lewis, John S. (2004). Physics & Chemistry of the Solar System. Centaurs & Trans-Neptunian Objects. Academic Press. pp. 409–412. ISBN   012446744X . Retrieved 2019-07-21.
  4. Wan, X.-S; Huang, T.-Y. (2001). "The orbit evolution of 32 plutinos over 100 million year". Astronomy and Astrophysics. 368 (2): 700–705. Bibcode:2001A&A...368..700W. doi: 10.1051/0004-6361:20010056 .
  5. Yu, Qingjuan; Tremaine, Scott (1999). "The Dynamics of Plutinos". Astronomical Journal. 118 (4): 1873–1881. arXiv: astro-ph/9904424 . Bibcode:1999AJ....118.1873Y. doi:10.1086/301045. S2CID   14482507.