Since the year 2000, a number of Kuiper belt objects (KBOs) with diameters of between 500 and 1500 km (more than half that of Pluto) have been discovered. 50000 Quaoar, a classical KBO discovered in 2002, is over 1000 km across. and , both announced on 29 July 2005, are larger still. Other objects, such as 28978 Ixion (discovered in 2001) and 20000 Varuna (discovered in 2000) measure roughly 500 km across. This has gradually led to the acceptance of Pluto as the largest member of the Kuiper belt.
The brightest known dwarf planets and other KBOs (with absolute magnitudes < 4.0) are:
NumberPermanentDesignationProvisionalDesignationAbsolute magnitudeBond Albedo (%)Semimajor axis(AU)Equatorial diameter(km)Date foundDiscovererDiameter method 134340 −0.8 72 39.4 2377 1930 C. Tombaugh direct imaging 136472 −0.2 80 45.6 1430 2005 M. Brown, C. Trujillo, D. Rabinowitz occultation 136108 0.2 51 43.3 1595 2003 Sierra Nevada Observatory (unofficial) occultation Charon S/1978 P 1 1.0 20 to 50 (geometric) 39.4 1212 1978 J. Christy direct imaging 90482 Orcus 2.2 23 39.3 910 2004 M. Brown, C. Trujillo, D. Rabinowitz thermal 50000 Quaoar 2.4 11 43.7 1070 2002 C. Trujillo, M. Brown thermal 174567 Varda 3.2 10 46.1 705 2003 J. A. Larsen estimated 55565 Aya 3.3 11 47.2 768 2002 NEAT thermal 55636 3.4 88 43.2 286 2002 NEAT Haumea family, estimated 202421 3.5 20 43.2 498 2005 Palomar estimated 307261 Máni 3.6 5 42.0 934 2002 C. Trujillo, M. Brown thermal 208996 Achlys 3.6 10 39.4 772 2003 C. Trujillo, M. Brown thermal 20000 Varuna 3.6 11 42.3 678 2000 Spacewatch thermal 55637 Uni 3.6 11 42.5 665 2002 Spacewatch thermal 28978 Ixion 3.6 14 39.8 617 2001 DES thermal 145452 Ritona 3.7 11 41.6 679 2005 A. C. Becker, A. W. Puckett, J. Kubica thermal 120178 3.9 70? 43.4 218? 2003 M. Brown, C. Trujillo, D. Rabinowitz Haumea family, estimated
See also List of trans-Neptunian objects
References