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'''Trans-Neptunian Objects''' are objects that lie outside the orbit of Neptune.  The objects are too small to have been discovered until only recently. Pluto was the first trans-Neptunian object to be discovered in 1930.<ref>http://www.planetary.org/explore/topics/trans_neptunian_objects/</ref> The [[Kuiper belt]], [[Scattered disk]], and [[Oort Cloud]] are names for three divisions of this volume of space.<ref>http://www.answers.com/topic/trans-neptunian-object</ref>

{{OortKuiperSedna}}'''Trans-Neptunian Objects''' are objects having [[semi-major axis|semi-major axes]] larger than that of the [[planet]] [[Neptune]].<ref name=planetsoc1>"[http://www.planetary.org/explore/topics/trans_neptunian_objects/ Space Topics: Trans-Neptunian Objects]." The Planetary Society, n.d. Accessed June 24, 2008.</ref>

== List of Trans-Neptunian Objects ==

== Naming conventions ==

A significant number of [[Astronomy|astronomers]] today insist that all trans-Neptunian objects, regardless of whether Neptune has any gravitational influence upon them, should be called [[Kuiper belt]] objects.<ref name=Jewitt>Jewitt, David. "[http://www.ifa.hawaii.edu/faculty/jewitt/kb.html Kuiper Belt]." University of Hawaii, n.d. Accessed June 20, 2008.</ref><ref name=Johnston>Johnston, William Robert. "[http://www.johnstonsarchive.net/astro/tnos.html Trans-Neptunian Objects]." October 1, 2007. Accessed June 24, 2008.</ref>But today, an increasing number of astronomers distinguish the Kuiper belt from other trans-Neptunian regions, primarily using orbital characteristics as the criterion for this distinction.<ref name=planetsoc2>"[http://www.planetary.org/explore/topics/trans_neptunian_objects/facts.html Types of Trans-Neptunian Objects]." The Planetary Society, n.d. Accessed June 24, 2008.</ref>

The list is long - a link to a website at [[Harvard]] with a list of Trans-Neptunian objects can be found here:<br />

Since 1951, when [[Gerard P. Kuiper]] published his original hypothesis concerning non-accreted icy remnants of the [[nebula hypothesis|solar nebula]], trans-Neptunian objects, by whatever name, have been held to be the source of [[comets]], of periods long or short.

[http://www.cfa.harvard.edu/iau/lists/TNOs.html List Of Transneptunian Objects]

{{Invert-property|Member of|Includes}}[[Image:LargeTNO.jpg|250px|right]]Trans-Neptunian objects today belong to four major classes (not counting the [[Centaurs]], an entirely different class of object):

== Notable Trans-Neptunian Objects ==

* The [[Kuiper belt]], containing those objects that remain between 30 and 50 AU distant from the [[Sun]]<ref name=planetsoc2/>

* The [[scattered disk]], containing objects having [[apsis|perihelia]] of 30 AU or greater and semi-major axes of 50 AU or greater.<ref name=planetsoc2/>

* The [[Oort cloud]], the hypothetical and probably factitious sphere of icy objects held to be the source of long-period comets<ref name=planetsoc2/>

== Discovery and observation ==

The first-ever trans-Neptunian object to be discovered was the [[dwarf planet]] [[Pluto]] in 1930. The next was Pluto's largest satellite [[Charon]] in 1978.<ref name=Whitman>Whitman, Justine. "[http://www.aerospaceweb.org/question/astronomy/q0270.shtml Pluto and the Kuiper Belt]." <Aerospaceweb.org>, Apriil 16, 2006. Accessed June 24, 2008.</ref> After the discovery of object [[1992 QB1]], astronomers have discovered more than 800 of these objects, but not nearly as many as some astronomers have predicted. Other notable TNO's that have been discovered include:

(15760) 1992 QB1, the prototype cubewano, the first Kuiper belt object discovered after Pluto and Charon<br />

(15874) 1996 TL66, the first scattered disk object to be recognized<br />

(48639) 1995 TL8, the earliest discovered scattered disc object, and a binary

1993 RO, the next plutino discovered after Pluto<ref>http://www.answers.com/topic/trans-neptunian-object</ref><br />  

== References ==

== References ==

<references/>

 

* [http://cfa-www.harvard.edu/iau/lists/TNOs.html List of Transneptunian Objects]." [[Harvard University]], Cambridge, [[Massachusetts]]. Updated daily. Accessed June 24, 2008.

 

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[[Category:Astronomy]]

[[Category:Astronomy]]