Trans Neptunian Object

Clathrate hydrates have been found to occur naturally in large quantities. Around 120 X 10 m (at STP) of methane is estimated to be trapped in deposits of the deep ocean floor [10]. Clathrate hydrates are also suspected to occur in large quantities on some outer planets, moons, and trans-Neptunian objects [11]. In the petroleum industry, hydrocarbon clathrate hydrates are a cause of problems because they can form inside gas pipelines, often resulting in plugging. Deep sea deposition of carbon dioxide clathrate hydrate has been proposed as a method to remove this greenhouse gas from the atmosphere and control climate change [12]. 

Morbidelh A., Thomas F., and Moons M. (1995) The resonant structure of the Kuiper Belt and the dynamics of the first five trans-Neptunian objects. Icarus 118, 322-340. 

The restricted three-body problem Two bodies of finite masses, called primaries, revolve around their common center of mass in circular orbits and a third body with negligible mass moves under their gravitational attraction, but does not affect the orbits of the two primaries. In most astronomical applications the second primary has a small mass compared to the first primary, and consequently the motion of the third, massless, body is a perturbed Keplerian orbit. This is a model for the study of an asteroid (Jupiter being the second primary), a trans-Neptunian object (Neptune being the second primary) or an Earth-like planet in an extrasolar planetary system. 

Trans-Neptunian Object (TNO) Any object in the solar system that orbits the sun at a greater average distance than Neptune. 

The International Astronomical Union passed resolutions in August 2006 that defined Pluto as a dwarf planet and recognized it as the prototype of a new category of TranS Neptunian Objects. See . 

Pluto A trans-Neptunian object that is the second largest dwarf planet so far known and the tenth largest body in the solar system. It was discovered in 1930 by Clyde... 

Many bodies are candidates for dwarf planet status. They include the trans-Neptunian objects Orcus, Ixion, Huya, Varuna, Quaoar, and Sedna. 

All planets from Mercury to Neptune and most of their satellites have been observed from Earth-based telescopes and at least once, some repeatedly, from spacecraft. Therefore, sufficient information was available to emphasize the physical principles in the discussions in Chapter 6. Trans-Neptunian objects and asteroids have been explored to a much lesser degree. Their small sizes, for many their large heliocentric distances, and their low surface temperatures prevented detailed exploration. Until recently, only a few samples of an enormous amount of objects have been investigated. Therefore, the treatment of these objects, grouped in this chapter, is primarily a summary of presently known properties. Section 7.1 discusses Pluto and its satellite Charon Section 7.2 is devoted to comets and Section 7.3 to asteroids. 

Asteroids, comets and smaller particles are also grouped into SSSBs, small solar system bodies. All categories of objects described above appear at specific locations in the solar system. The inner solar system contains the terrestrial planets and the Main Belt of asteroids. In the middle region there are the giant planets with their satellites and the centaurs. The outer solar system comprises the Trans-Neptunian objects including the Kuiper Belt, the Oort cloud, and the vast region in between. 

For example, the diameter of Pluto and Eris is nearly the same, about 2400 km, the semi major axis of Pluto is 39.5 AU (high eccentric, orbital radius between 29.66 and 49.3 AU), that of Eris 67.67 AU (high eccentric, orbital radius between 37.77 and 97.56 AU). Ceres has a diameter of 975 x 909 km and the semi major axis is 2.76 AU. Pluto is also regarded as a prototype of Trans Neptunian Objects (TNOs). 

Sedna is, so far, the largest and most distant trans-neptunian object. It was observed with the two 8.2 m VLT telescopes of ESO (Cerro Paranal, Chile). From its spectrum it was deduced that more than 50% of the surface could be covered with ice and the presence of N2 and CH4 was confirmed. One revolution of Sedna takes more than 10 500 years but during about 200 years, when this object is close to the Sun, a thin atmosphere of N2 may form (Barucci et al. 2005, [20]). 

We just mention that there is a confusion about naming. The term Trans Neptunian Object (TNO) is used for objects at the outer edge of the Solar system (see Fig. 5.1) here, the KBO are only a subset. Also the term Edgeworth-Kuiper belt is used, and the objects are called EKOs. A review on Trans Neptunian Objects was given by Schulz, 2002 [299]. Many objects are found near the 1 2 resonance with Neptune (while Neptune completes two revolutions about the Sun, the KBO completes only one). 

Largest known trans-Neptunian objects (TNOs)... 

Pig. 5.1 Comparison of some known Trans Neptunian Objects, TNOs. Courtesy A. Feild (Space Telescope Science Institute)... 

Fulvio, D., Guglielmino, S., Favone, T., Palumbo, M.E. Near-infrared laboratory spectra of H2O trapped in N2, CH4, and CO hints for trans-Neptunian objects observations. Astron. Astrophys. 511,62 (2010)... 

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