It is difficult to estimate the diameter of TNOs. For very large objects, with very well known orbital elements (namely, Pluto and Charon), diameters can be precisely measured by occultation of stars.

For other large TNOs, diameters can be estimated by thermal measurements. The intensity of light illuminating the object is known (from its distance to the Sun), and one assumes that most of its surface is in thermal equilibrium (usually not a bad assumption for an airless body). For a known albedo, it is possible to estimate the surface temperature, and correspondingly the intensity of heat radiation. Further, if the size of the object is known, it is possible to predict both the amount of visible light and emitted heat radiation reaching the Earth. A simplifying factor is that the Sun emits almost all of its energy in visible light and at nearby frequencies, while at the cold temperatures of TNOs, the heat radiation is emitted at completely different wavelengths (the far infrared).

Thus there are two unknowns (albedo and size), which can be determined by two independent measurements (of the amount of reflected light and emitted infrared heat radiation).

Unfortunately, TNOs are so far from the Sun that they are very cold, hence produce black-body radiation around 60 micrometres in wavelength. This wavelength of light is impossible to observe on the Earth's surface, but only from space using, e.g., the Spitzer Space Telescope. For ground-based observations, astronomers observe the tail of the black-body radiation in the far infrared. This far infrared radiation is so dim that the thermal method is only applicable to the largest KBOs. For the majority of (small) objects, the diameter is estimated by assuming an albedo. However, the albedos found range from 0.50 down to 0.05 resulting, as example for magnitude of 1.0, in uncertainty from 1200 – 3700 km![3].

[

Largest discoveries

It has been suggested that this article or section be merged into dwarf planet. (Discuss)

Currently lying at 97 AU away, Eris is the farthest known object in the solar system, and the third brightest of the TNOs. Classified as a scattered disk object (SDO), Eris follows an orbit at 10 billion kilometres from the Sun, completing it in 560 years at an unusual 45-degree angle.

The brightest known TNOs (with absolute magnitudes < 4.0), are:

Permanent Designation	Provisional Designation	Absolute magnitude	Albedo	Equatorial diameter (km)	Semimajor axis (AU)	Class	Discovery date	Discoverer(s)	Diameter method
(136199) Eris	2003 UB313	−1.2	~0.86 ± 0.07	2400 ± 100	67.7	SDO	2005	M. Brown, C. Trujillo & D. Rabinowitz	thermal
(134340) Pluto		−1.0	0.49 to 0.66	2306 ± 20	39.4	KBO	1930	C. Tombaugh	occultation
Charon	S/1978 P 1	1	0.36 to 0.39	1205 ± 2	39.4	KBO satellite	1978	J. Christy	occultation

TNOs that are larger or comparable in diameter to Ceres

Name	Category	Estimated diameter (km)				Mass (×1020 kg)	Orbital radius (AU)
			by [13]	by [14]	by [15]
2003 EL61	cubewano	2000	1380	1350	1200	~42	43.31
Sedna	extended-SDO	1800	1500	<1800	<1500	17–61	486.0
2005 FY9	cubewano	1600	1500	1500	1250	~40	45.66
Quaoar	cubewano	1290	1260	1260	1200	10–26	43.58
Orcus	plutino	1100	909	946	1500	6.2–7.0	39.34
Ixion	plutino	980	570	650	1065	~5.8	39.65
Ceres	asteroid	975				9.5	2.77
2002 AW197	cubewano	940	793	977	890	~5.2	47.30
Varuna	cubewano	780	874	1016	900	~5.9	42.90
2002 TC302	SDO	710	1200	1150	—	0.78	55.02

The list has been sorted by increasing absolute magnitude. Estimated diameter is greatly affected by surface albedo which has often been assumed, not measured. Some potentially large Kuiper belt objects have not been included.

Sources:^{[16][17][18][19]}

[

External links

• Minor Planet Center List of Transneptunian Objects
• TNO Italian website An Italian website about TNO
• Nine planets, University of Arizona
• David Jewitt's Kuiper Belt site
  • Large KBO page
• A list of the estimates of the diameters from jonhnstonarchive with references to the original papers
• Trans-Neptunian Object Orbital Database TNO Orbital Database

[

See also

• List of trans-Neptunian objects
• Triton
• Nemesis
• Dwarf planet
• Mesoplanet
• Small solar system body

[

References

1. ^ List of Transneptunian obects
2. ^ Evidence for an Extended Scattered Disk?
3. ^ D.Jewitt, A.Delsanti The Solar System Beyond The Planets in Solar System Update : Topical and Timely Reviews in Solar System Sciences , Springer-Praxis Ed., ISBN 3-540-26056-0 (2006) Preprint of the article (pdf)
4. ^ Rodney S. Gomes, John J. Matese, and Jack J. Lissauer A Distant Planetary-Mass Solar Companion May Have Produced Distant Detached Objects To appear in Icarus (2006). Preprint
5. ^ J. L. Elliot, S. D. Kern, K. B. Clancy, A. A. S. Gulbis, R. L. Millis, M. W. Buie, L. H. Wasserman, E. I. Chiang, A. B. Jordan, D. E. Trilling, and K. J. Meech The Deep Ecliptic Survey: A Search for Kuiper Belt Objects and Centaurs. II. Dynamical Classification, the Kuiper Belt Plane, and the Core Population. The Astronomical Journal, 129 (2006), pp. preprint
6. ^ ^{a b} David L. Rabinowitz, K. M. Barkume, Michael E. Brown, H. G. Roe, M. Schwartz, S. W. Tourtellotte, C. A. Trujillo (2005), Photometric Observations Constraining the Size, Shape, and Albedo of 2003 El₆₁, a Rapidly Rotating, Pluto-Sized Object in the Kuiper Belt, Astrophysical Journal, submitted Preprint on arXiv
7. ^ ^{a b} N. Peixinho, A. Doressoundiram, A. Delsanti, H. Boehnhardt, M. A. Barucci, and I. Belskaya Reopening the TNOs Color Controversy: Centaurs Bimodality and TNOs Unimodality Astronomy and Astrophysics, 410, L29-L32 (2003). Preprint on arXiv(pdf)
8. ^ O. R. Hainaut & A. C. Delsanti (2002) Color of Minor Bodies in the Outer Solar System Astronomy & Astrophysics, 389, 641 datasource
9. ^ A. Doressoundiram, N. Peixinho, C. de Bergh, S. Fornasier, Ph. Thébault, M. A. Barucci and C. Veillet The color distribution in the Edgeworth-Kuiper Belt The Astronomical Journal, 124, pp. 2279-2296. Preprint on arXiv
10. ^ Gulbis, Amanda A. S.; Elliot, J. L.; Kane, Julia F. The color of the Kuiper belt Core Icarus, 183 (July 2006), Issue 1, p. 168-178.
11. ^ Michael E. Brown. The Dwarf Planets. California Institute of Technology, Department of Geological Sciences. Retrieved on 2008-01-26.
12. ^ A. Barucci Trans Neptunian Objects’ surface properties, IAU Symposium #229, Asteroids, Comets, Meteors, Aug 2005, Rio de Janeiro
13. ^ Johnston, Robert (2007-11-24). List of Known Trans-Neptunian Objects. Johnston's Archive.net. Retrieved on 2008-01-26.
14. ^ Barucci, M.A.; Stansberry, John; Grundy, Will; Brown, Mike; Cruikshank, Dale; Spencer, John; Trilling, David; Margot, Jean-Luc (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". The Solar System beyond Neptune. University of Arizona Press. 
15. ^ David Jewitt. Kluipert Belt: The 1000 km Scale KBOs. University of Hawaii, Institute for Astronomy. Retrieved on 2008-02-10.
16. ^ Grundy et al. Diverse Albedos of Small Trans-Neptunian Objects Icarus Notes. Preprint on arXiv (pdf)
17. ^ Dale P. Cruikshank et al. Albedos, Diameters (and a Density) of Kuiper Belt and Centaur Objects from a session of the 37th meeting of the Division for Planetary Sciences of the American Astronomical Society and the Royal Astronomical Society (September 2005, Cambridge, UK) Abstract
18. ^ The original press release announcing the measuring of the albedo of 2003 UB₃₁₃ by Bertoldi et al.
19. ^ MPC Circular 2006-A28 for 2003 MW₁₂ data

v • d • e Trans-Neptunian dwarf planets and candidates Kuiper belt Orcus · 2003 AZ84 · Ixion · Pluto · 2005 RN43 · 2002 MS4 · 2002 UX25 · Varuna · 2003 EL61 · 2002 TX300 · 2005 UQ513 · Quaoar · 2005 FY9 · 2003 MW12 · 2002 AW197 Scattered disc 2002 TC302 · 2006 QH181 · Eris · 2007 UK126 · 2005 QU182 · Sedna See also Triton · Astronomical objects and List of objects in the Solar System (by radius · by mass) For a pronunciation guide, see Centaur and TNO pronunciation.

v • d • e Small Solar System bodies Asteroids (Vulcanoids · Near-Earth · Main belt · Jupiter Trojans · Centaurs · Damocloids · Neptune Trojans · Groups · Families · Moons) Comets · Trans-Neptunians (Kuiper belt · Scattered disc objects · Oort cloud) · Minor planets · Meteoroids Lists: Minor planets · Asteroid groups and families · Binary asteroids · Asteroid moons See also: Near-Earth object · Dwarf planet · Planet · Solar System · Pronunciation of asteroid names · Meanings of asteroid names.

v • d • e The Solar System The Sun · Mercury · Venus · Earth · Mars · Ceres · Jupiter · Saturn · Uranus · Neptune · Pluto · Eris Planets · Dwarf planets · Moons: Terrestrial · Martian · Jovian · Saturnian · Uranian · Neptunian · Plutonian · Eridian Small bodies:   Meteoroids · Asteroids/Asteroid moons (Asteroid belt) · Centaurs · TNOs (Kuiper belt/Scattered disc) · Comets (Oort cloud) See also astronomical objects, the Solar System's list of objects, sorted by radius or mass, and the Solar System Portal

v • d • e Trans-Neptunian objects Pronunciation guide Objects in italics are unnnumbered. Plutinos Pluto1 · 1993 SB · 1993 SC · 1994 JR1 · 1994 TB · 1995 QZ9 · 1996 SZ4 · 1996 TP66 · 1996 TQ66 · 1997 QJ4 · 1998 HK151 · 1998 US43 · 1998 VG44 · 1998 WW24 · 1998 WU31 · 38083 Rhadamanthus · 1999 TC36 · 38628 Huya · 28978 Ixion · 2002 KX14 · 2002 VR128 · 2003 VS2 · 90482 Orcus · 1993 RO · 1993 RP · 2003 AZ84 · 2001 QF298 Cubewanos 1992 QB1 · 1994 GV9 · 1994 JQ1 · 1994 VK8 · 1995 GJ · 1995 SM55 · 1996 TO66 · 58534 Logos · 1997 CS29 · 1997 CU29 · 1998 HJ151 · 1998 HP151 · 1998 HM151 · 1998 KR65 · 19521 Chaos · 1998 WA25 · 1999 DF9 · 1999 HT11 · 53311 Deucalion · 20000 Varuna · 2002 AW197 · 50000 Quaoar · 2002 TX300 · 2002 UX25 · 2003 EL61 · 2003 OP32 · 2004 GV9 · 2005 FY9 · 2005 RN43 · 88611 Teharonhiawako · 1998 WW31 · 2002 MS4 · 2003 MW12 · 2003 QW90 Twotinos 1996 TR66 · 1998 SM165 · 1999 RB216 · 2000 JG81 · 2002 WC19 · 1997 SZ10 Other resonant objects 1994 JS · 1995 DA2 · 1998 WA31 · 1999 CP133 · 1999 DE9 · 1999 HB12 · 2001 KC77 · 2001 KP77 · 2002 TC302 · 2003 LG7 Scattered disc objects Eris1, 2 · 1995 TL8 · 1996 GQ21 · 1996 TL66 · 1999 CC158 · 2000 EE173 · 2000 OO67 · 2000 OM67 · 2001 UR163 · 2002 CY224 · 2002 GX32 · 2002 RP120 · 90377 Sedna2 · 2005 RM43 · 2000 CR105 2004 XR190 · 2005 TN74 · 2006 QH181 Unclassified 1997 CR29 · 1998 SN165 · 1999 CL158 · 1999 HC12 · 1999 KR16 · 1999 OY3 · 2003 FY128 · 2004 SB60 · 2004 TY364 · 2005 RR43 Natural satellites Charon (Pluto) · Hydra (Pluto) · Nix (Pluto) · Dysnomia (Eris) · S/2000 (1998 WW31) 1 · S/2005 (2003 EL61) 1 · S/2005 (2003 EL61) 2 · Zoe (Logos) · S/2005 (79360) 1 · Sawiskera (Teharonhiawako) 1 Also classified as a dwarf planet. 2 Although currently classified as an SDO, Eris and Sedna may be part of the inner Oort Cloud.

BCUZ.com FACTS Encyclopedia content is licensed under the GFDL as approved by Wikipedia.
For more information review our copyright contact and privacy policy. © 1996 - BCUZ.COM - We have all the FACTS you need about Small Business Financing, Behavior Disorder, Having Too Many Bills, Needing Cash Fast, Structured Settlements, Frequent Flier Programs, Top Steak Houses, The Mayan Indians, Norfolk and Suffolk England, Growing Longer Hair and a full reference English Encyclopedia and Spanish Encyclopedia.Privacy Policy