Transneptunian Asteroids

TNOs

The TNOs (Trans Neptunian Objects) are objects orbiting beyond the orbit of Neptune, extending beyond 50 ua from the Sun. The existence of asteroidal bodies in that region of space was theorized in 1951 by Gerard Kuiper (and before him, in 1943, by Kenneth Edgeworth): fro this reason the objects predicted by this model are often called Kuiper (or Kuiper-Edgeworth) Objects (KBOs).

The first TNO was discovered in 1992; after that date, and up to now, their numbers are continuously increasing, and today many hundreds are known. Orbital similarities, as the 3:2 resonance with Neptune, between many of these objects and Pluto, lead many to consider the latter not as a planet, but as the major representative of the KBOs family, as decided by the IAU in August 2006, when the Solar System lost its ninth planet.

Unfortunately, because of the great distance from Earth and the small size, the relative magnitude of most of the TNOs is often greater than 20. This aspect, makes them extremely faint and hard to observe with amateur-level instruments. Only a very limited number of them keeps a brightness below this value.

In the following all the TNOs within reach of our instruments are listed (Mag. < 20,4). Objects classified as Centaurs are included, although they orbit in the outer Solar System, and not properly in the trans-neptunian region.
The objects with pictures have already been observed, while the remaining are planned for the future.

The classification is shown after the ID number:
Cen (Centaur), Cub (Cubewano, or classical KBO), Plu (Plutino, resonant 2:3), Res (Resonant, but not Plutino), SDO (Scattered Disc Object)

Plutone - Dedicated website: (134340) Pluto (Plu)
(29 and 30 July 2000 - Mag. 13,8)
(145452) 2005RN43 (Cub)
(20 October 2012 - Mag. 19,7)
2010RM64 (Cen)
(21 October 2012 - Mag. 18,3)
(343842) 2008YB3 (Cen)
(23 December 2011 - Mag. 17,5)
(230965) 2004XA192 (Cen)
(22 November 2011 - Mag. 19,2)
(346889) 2009QV38 (Cen)
(22 December 2011 - Mag. 19,7)
(310071) 2010KR59 (Cen)
(6 April 2011 - Mag. 18,8)
(281371) 2008FC76 (Cen)
(22 September 2011 - Mag. 19,4)
(250112) 2002KY14 (Cen)
(9 October 2010 - Mag. 19,2)
2010BK118 (Cen)
(9 October 2010 - Mag. 18,5)
(54598) Bienor (Cen)
(11 November 2009 - Mag. 19,5)
(120178) 2003OP32 (Cub)
(19 July 2009 - Mag. 19,9)
(281371) 2008FC76 (Cen)
(21 July 2009 - Mag. 19,5)
(60558) Echeclus (Cen)
(23 March 2009 - Mag. 18,6)
 
(55565) 2002AW197 (Cub)
(22 March 2009 - Mag 19,9)
.
(42355) Typhon (SDO)
(19 March 2009 - Mag. 19,6)
(208996) 2003AZ84 (Plu)
(18 February 2009 - Mag. 20,2)

.(229762) 2007UK126 (SDO)
(29 January 2009 - Mag 20,0)

(145486) 2005UJ438 (Cen)
(26 December 2008 - Mag. 19,6)
(145453) 2005RR43 (Cub)
(6 December 2008 - Mag. 19,2)
(55638) 2002VE95 (Plu)
(7 December 2008 - Mag. 18,6)
 
.
(32532) Thereus (Cen)
(19 November 2008 - Mag. 19,1)
(2060) Chiron (Cen)
(19 October 2008 - Mag. 17,6)
.
.(8405) Asbolus (Cen)
(19 October 2008 - Mag. 19,7)
 
(250112) 2002 KY14 (Cen)
(6 October 2008 - Mag. 19,0)
(47171) 1999TC36 (Plu)
(6 October 2008 - Mag. 19,8)
 
(26375) 1999DE9 (Res)
(14 March 2008 - Mag. 20,4)
 
(52872) Okyrhoe (Cen)
(03 March 2008 - Mag. 18,2)
 
(90482) Orcus (Plu)
(10 February 2008 - Mag. 19,1)
(145451) 2005RM43 (SDO)
(7 February 2008 - Mag. 18,9)
(84922) 2003VS2 (Plu)
(5 February 2008 - Mag. 19,9)
 
(55637) 2002UX25 (Cub)
(29 December 2007 - Mag. 20,1)
(38628) Huya (Plu)
(12 May 2007 - Mag. 19,6)
(28978) Ixion (Plu)
(12 July 2007 - Mag. 19,7)
(20000) Varuna (Cub)
(12 January 2007 - Mag. 20,0)
2006 EX52 (TNO)
(14 December 2006 - Mag. 18,8)
(136199) Eris (SDO)
(1 August 2005 - Mag. 18,7)
(136108) Haumea (Cub)
(31 July 2005 - Mag. 17,5)
(136472) Makemake (Cub)
(31 July 2005 - Mag. 16,9)
(55636) 2002TX300 (Cub)
(22 August 2003 - Mag. 19,7)
(50000) Quaoar (Cub)
(3 July 2004 - Mag. 18,6)

Useful links: http://www.boulder.swri.edu/ekonews/
                  

Wladimiro MARINELLO