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. Makemake and Haumea, 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.[1] This has led gradually to the acceptance of Pluto as the largest member of the Kuiper belt.[citation needed]
The brightest known dwarf planets and other KBOs (with absolute magnitudes < 4.0) are:
| Number | Permanent Designation[2] |
Provisional Designation[2] |
Absolute magnitude[3] |
Bond Albedo (%)[2] | Semimajor axis (AU)[3] |
Equatorial diameter (km)[2] |
Date found[2] | Discoverer[3] | Diameter method[4] |
|---|---|---|---|---|---|---|---|---|---|
| 134340 | Pluto | −0.8 | 72 | 39.4 | 2377 | 1930 | C. Tombaugh | direct imaging | |
| 136472 | Makemake | 2005 FY9 | −0.2 | 80 | 45.6 | 1430 | 2005 | M. Brown, C. Trujillo, D. Rabinowitz | occultation |
| 136108 | Haumea | 2003 EL61 | 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 | 2004 DW | 2.2 | 23 | 39.3 | 910 | 2004 | M. Brown, C. Trujillo, D. Rabinowitz | thermal |
| 50000 | Quaoar | 2002 LM60 | 2.4 | 11 | 43.7 | 1070 | 2002 | C. Trujillo, M. Brown | thermal |
| 174567 | Varda | 2003 MW12 | 3.2 | 10 | 46.1 | 705 | 2003 | J. A. Larsen | estimated |
| 55565 | 2002 AW197 | 3.3 | 11 | 47.2 | 768 | 2002 | NEAT | thermal | |
| 55636 | 2002 TX300 | 3.4 | 88 | 43.2 | 286 | 2002 | NEAT | Haumea family, estimated | |
| 202421 | 2005 UQ513 | 3.5 | 20 | 43.2 | 498 | 2005 | Palomar | estimated | |
| 307261 | 2002 MS4 | 3.6 | 5 | 42.0 | 934 | 2002 | C. Trujillo, M. Brown | thermal | |
| 208996 | 2003 AZ84 | 3.6 | 10 | 39.4 | 772 | 2003 | C. Trujillo, M. Brown | thermal | |
| 20000 | Varuna | 2000 WR106 | 3.6 | 11 | 42.3 | 678 | 2000 | Spacewatch | thermal |
| 55637 | 2002 UX25 | 3.6 | 11 | 42.5 | 665 | 2002 | Spacewatch | thermal | |
| 28978 | Ixion | 2001 KX76 | 3.6 | 14 | 39.8 | 617 | 2001 | DES | thermal |
| 145452 | 2005 RN43 | 3.7 | 11 | 41.6 | 679 | 2005 | A. C. Becker, A. W. Puckett, J. Kubica | thermal | |
| 120178 | 2003 OP32 | 3.9 | 70?[4] | 43.4 | 218?[4] | 2003 | M. Brown, C. Trujillo, D. Rabinowitz | Haumea family, estimated |
See also
editReferences
edit- ^ Audrey Delsanti & David Jewitt. "The Solar System Beyond The Planets" (PDF). Institute for Astronomy, University of Hawaii. Archived from the original (PDF) on 2007-01-29. Retrieved 2007-03-09.
- ^ a b c d e Johnston, W. R. (7 October 2018). "List of Known Trans-Neptunian Objects". Retrieved 6 February 2019.
- ^ a b c "List of Transneptunian Objects". Minor Planet Center. Retrieved 6 February 2019.
- ^ a b c Brown, M. (12 November 2018). "How many dwarf planets are there?". Retrieved 6 February 2019.
