Kuiper Belt Objects KBOs

Distinguish between comets, Kuiper Belt Objects (KBOs), and Oort cloud objects. 

Like the Oort cloud, the Kuiper Belt was initially hypothetical but, due to its proximity, techniques were eventually developed so that the larger Kuiper Belt objects (KBOs) could be telescopically detected from Earth. In 1992 the first KBO was discovered by Jewitt and Luu (1993). It was a 23rd magnitude object with a diameter of —320 km at an average solar distance of 44 AU. By the end of 2002, over 700 KBOs had been discovered, over 500 since the beginning of 1999. The dramatic rise in detection was due to heroic... 

Pluto - a Kuiper belt object ((KBO), considered to be a planet from its discovery in 1930 until 2006. It is named after the Greek god of the underworld. 

The Kuiper belt extends from about the orbit of Neptune (30 AU) to about 55 AU and even more. The first Kuiper Belt Object, KBO, was discovered in 1992, presently several thousand KBOs are known. Their total number is estimated over 70 000 for objects over 100 km in diameter. It can be compared with the asteroid belt which occurs between the orbits of Mars and Jupiter but there are two important differences ... 

The effect of heating and resultant radiation of any orbiting dust cloud particles around red giants should be also detectable in the IR. The Kuiper belt objects (KBO) start to sublimate because they are heated up to 170 K. This leads to an IR excess at 25 pm. 

Pluto, with a diameter of 2300 km, has now been demoted from the smallest planet to one of the largest Kuiper belt objects. Pluto and its satellite Charon could be considered a binary system because they are closer in size than any other known celestial pair in the solar system and the barycenter of their orbits does not lie within either body. There are also two smaller moons, Nix and Hydra. All four bodies are likely KBOs with similar compositions. Pluto has a thin atmosphere containing N2, with minor CH4, CO, and Ar. Curiously, the face of Pluto oriented towards Charon contains more methane ice, and the opposite face contains more nitrogen and carbon monoxide ice. 

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). 

A Pluto sized object in the Kuiper belt is 2003 ELes. Its apparent visual magnitude is 17.5 at a distance of 51 AU from the Sun. It is the third brightest KBO after Pluto and 2005 FY9. The rotation period is 3.9 hr and the amplitude of its lightcurve is 0.28 mag which is a very fast rotation for a body larger than 100 km. The data are consistent with a diameter ranging from 1960 to 2500 km and a mean density of 2.6-3.3 gcm and a visual albedo greater than 0.6 indicating an icy surface (Rabinowitz et al., 2006 [270]). 

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