TNOs: a vs. e (semi-log plot, 30–1000 AU): Distribution of 5,630 listed TNO objects (with a > 30.1 AU) by subclass from Johnston's Archive (hover)
This is a list of unnumbered trans-Neptunian objects (TNOs) first observed since 1993 and grouped by the year of principal provisional designation. The data is sourced from the Minor Planet Center's (MPC) List of Trans Neptunian Objects, List Of Centaurs and Scattered-Disk Objects, List Of Other Unusual Objects, and Database Search. These objects will eventually be numbered as secured discoveries with an official discoverer determined by the MPC. Until then, additional observations are needed to sufficiently decrease an object's orbital uncertainty. , there are 6,218 unnumbered objects, defined here as minor planets with a semi-major axis larger than 30.1 AU (Neptune's average orbital distance from the Sun).
The list also contains information from "Johnston's Archive", such as an object's diameter, its dynamical class and binary status with the satellite's diameter, as well as its albedo, spectral taxonomy and B–R color index. Members of the extreme trans-Neptunian objects (ESDOs, EDDOs and sednoids) – with a semi-major axis greater than 150 AU and perihelion greater than 30 AU – are also identified.
Statistics
List
1993 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 15 September 1993 D. C. Jewitt, J. X. Luu () 50 res4:5 35.3 0.06 4 33.1 37.5 albedo: 0.126
1994 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 13 March 1994 J. X. Luu, D. C. Jewitt () 83 cubewano (cold) 45.8 0.11 1 40.6 50.9 albedo: 0.152; BRmag: 1.65 3 October 1994 Maunakea () 188 cubewano (hot) 42.3 0.00 7 42.3 42.3 albedo: 0.079 8 October 1994 European Southern Observatory, La Silla () 136 cubewano (cold)? 42.4 0.00 2 42.4 42.4 albedo: 0.152 3 October 1994 Maunakea () 147 other TNO 40.9 0.00 16 40.9 40.9 albedo: 0.13
1995 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 24 February 1995 D. C. Jewitt, J. X. Luu () 96 cubewano (cold) 46.5 0.14 4 40.1 53.0 albedo: 0.152 29 March 1995 Siding Spring Observatory () 108 cubewano (cold)? 42.4 0.00 1 42.4 42.4 albedo: 0.152 3 April 1995 Maunakea () 154 plutino? 39.5 0.12 4 34.8 44.2 albedo: 0.074 3 April 1995 Maunakea () 188 cubewano (hot)? 42.9 0.09 23 39.0 46.8 albedo: 0.079 6 April 1995 European Southern Observatory, La Silla () 108 cubewano (cold)? 41.3 0.00 1 41.3 41.3 albedo: 0.152 30 May 1995 Maunakea () 171 cubewano (cold)? 43.5 0.00 3 43.5 43.5 albedo: 0.152 30 May 1995 Maunakea () 74 other TNO 39.5 0.19 9 32.0 47.0 albedo: 0.13 24 December 1995 Maunakea () 74 other TNO 39.6 0.22 0 30.8 48.4 albedo: 0.13
1996 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 14 January 1996 Spacewatch () 76 centaur 35.8 0.62 11 13.6 58.0 albedo: 0.058 21 May 1996 C. A. Trujillo, D. C. Jewitt, J. X. Luu () 164 cubewano (hot) 45.0 0.11 8 40.2 49.9 albedo: 0.079 22 May 1996 Maunakea () 97 plutino? 39.5 0.10 2 35.7 43.4 albedo: 0.074 16 May 1996 Maunakea () 123 plutino? 39.5 0.10 31 35.7 43.3 albedo: 0.074 9 August 1996 NEAT () 10 damocloid 272.4 0.99 30 2.6 542.2 albedo: 0.048 6 September 1996 D. L. Rabinowitz () 185 cubewano (hot) 44.1 0.10 32 39.6 48.7 albedo: 0.079; BRmag: 1.57; taxonomy: IR
1997 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 8 February 1997 Maunakea () 245 plutino? 39.4 0.08 19 36.3 42.5 albedo: 0.074 3 April 1997 B. Gladman () 90 cubewano (hot)? 47.1 0.18 8 38.8 55.4 albedo: 0.079 27 August 1997 D. C. Jewitt, C. A. Trujillo, J. X. Luu, K. Berney () 188 cubewano (hot) 42.9 0.09 13 39.1 46.7 albedo: 0.079; BRmag: 1.94; taxonomy: RR 5 September 1997 Palomar Mountain () 60 cubewano (hot)? 44.5 0.00 6 44.5 44.5 albedo: 0.079 7 September 1997 B. Gladman () 103 cubewano (hot) 41.7 0.05 30 39.6 43.8 albedo: 0.079 6 September 1997 La Palma () 150 cubewano (hot) 41.4 0.00 12 41.4 41.4 albedo: 0.079 5 October 1997 Palomar Mountain () 94 cubewano (hot)? 39.3 0.19 9 32.0 46.6 albedo: 0.079 26 October 1997 La Palma () 68 cubewano (cold)? 43.3 0.00 1 43.3 43.3 albedo: 0.152
1998 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 23 March 1998 Northfield Mount Hermon School () 213 cubewano (hot) 41.7 0.02 10 40.7 42.7 albedo: 0.079; BRmag: 1.53; taxonomy: IR 29 April 1998 D. C. Jewitt, J. X. Luu, C. A. Trujillo, D. J. Tholen () 88 other TNO 40.6 0.09 28 36.9 44.3 albedo: 0.13; BRmag: 1.06 21 April 1998 J. Kormendy, R. Wainscoat, D. J. Tholen, D. C. Jewitt () 83 other TNO 37.9 0.05 25 35.9 39.8 albedo: 0.13 22 April 1998 R. Wainscoat, J. Kormendy, D. C. Jewitt, J. X. Luu () 108 cubewano (hot) 41.3 0.09 17 37.5 45.1 albedo: 0.079 28 April 1998 Maunakea () 90 cubewano (hot)? 45.5 0.12 7 39.9 51.1 albedo: 0.079 29 May 1998 Cerro Tololo Observatory, La Serena () 78 cubewano (hot)? 43.1 0.05 5 40.9 45.3 albedo: 0.079 29 May 1998 Cerro Tololo Observatory, La Serena () 54 cubewano (cold)? 42.1 0.00 3 42.1 42.1 albedo: 0.152 29 May 1998 Cerro Tololo Observatory, La Serena () 54 plutino? 39.5 0.21 6 31.1 47.9 albedo: 0.074 29 May 1998 Cerro Tololo Observatory, La Serena () 57 cubewano (cold)? 45.2 0.00 4 45.2 45.2 albedo: 0.152 29 May 1998 G. Bernstein () 101 cubewano (cold) 43.7 0.03 1 42.3 45.2 albedo: 0.152; BRmag: 1.73; taxonomy: RR-IR 29 May 1998 G. Bernstein () 119 cubewano (cold) 44.3 0.05 2 42.1 46.5 albedo: 0.152 22 October 1998 M. W. Buie () 106 plutino 39.8 0.23 9 30.8 48.9 albedo: 0.074; BRmag: 1.27; taxonomy: BR 18 November 1998 M. W. Buie () 107 plutino 39.7 0.21 7 31.5 47.9 albedo: 0.074; BRmag: 1.32; taxonomy: IR-BR 18 November 1998 M. W. Buie () 162 plutino? 39.2 0.04 2 37.8 40.7 binary: 106 km; albedo: 0.074; BRmag: 1.27; taxonomy: BR 19 November 1998 M. W. Buie () 118 plutino 39.5 0.27 6 28.9 50.2 albedo: 0.074; BRmag: 1.34; taxonomy: BR 18 November 1998 M. W. Buie () 145 cubewano (hot) 44.9 0.08 7 41.3 48.5 binary: 121 km; albedo: 0.16 18 November 1998 M. W. Buie () 156 cubewano (cold) 43.6 0.04 1 42.0 45.2 albedo: 0.152; BRmag: 1.79; taxonomy: RR 18 November 1998 M. W. Buie () 137 cubewano (cold) 45.5 0.12 2 40.0 51.0 albedo: 0.152 18 November 1998 Kitt Peak () 88 other TNO 39.5 0.18 5 32.4 46.6 albedo: 0.13 19 November 1998 M. W. Buie () 111 plutino 39.8 0.17 15 33.0 46.6 albedo: 0.074; BRmag: 1.26; taxonomy: IR-BR
1999–2007
List of unnumbered trans-Neptunian objects: 1999 List of unnumbered trans-Neptunian objects: 2000 List of unnumbered trans-Neptunian objects: 2001 List of unnumbered trans-Neptunian objects: 2002 List of unnumbered trans-Neptunian objects: 2003 List of unnumbered trans-Neptunian objects: 2004 List of unnumbered trans-Neptunian objects: 2005 List of unnumbered trans-Neptunian objects: 2006 List of unnumbered trans-Neptunian objects: 2007
2008 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 6 January 2008 P. A. Wiegert () 121 res4:7 43.9 0.16 1 37.0 50.8 albedo: 0.126 8 January 2008 Maunakea () 256 centaur 32.5 0.37 43 20.4 44.5 albedo: 0.058 30 January 2008 Spacewatch () 11 damocloid 35.2 0.93 29 2.6 67.8 albedo: 0.048 11 May 2008 Maunakea () 79 SDO 86.7 0.54 49 39.9 133.4 albedo: 0.124 7 June 2008 Maunakea () 81 other TNO 40.2 0.31 15 28.0 52.5 albedo: 0.13 27 August 2008 Maunakea () — — 46.1 0.18 8 37.8 54.5 — 7 October 2008 D. J. Tholen () 144 plutino 39.7 0.10 32 35.7 43.8 albedo: 0.074 26 October 2008 L. H. Wasserman () 220 res1:4 76.4 0.51 31 37.1 115.6 albedo: 0.126; taxonomy: BR
2009–2023
List of unnumbered trans-Neptunian objects: 2009 List of unnumbered trans-Neptunian objects: 2010 List of unnumbered trans-Neptunian objects: 2011 List of unnumbered trans-Neptunian objects: 2012 List of unnumbered trans-Neptunian objects: 2013 List of unnumbered trans-Neptunian objects: 2014 List of unnumbered trans-Neptunian objects: 2015 List of unnumbered trans-Neptunian objects: 2016 List of unnumbered trans-Neptunian objects: 2017 List of unnumbered trans-Neptunian objects: 2018 List of unnumbered trans-Neptunian objects: 2019 List of unnumbered trans-Neptunian objects: 2020 List of unnumbered trans-Neptunian objects: 2021 List of unnumbered trans-Neptunian objects: 2022 List of unnumbered trans-Neptunian objects: 2023
2024 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q 10 January 2024 WFST, Lenghu () 164 plutino 39.7 0.30 4 27.9 51.5 albedo: 0.074 7 February 2024 Cerro Tololo-DECam () 152 other TNO 58.4 0.10 84 52.6 64.2 albedo: 0.13 7 February 2024 Cerro Tololo-DECam () 150 other TNO 37.3 0.10 26 33.7 40.9 albedo: 0.13 18 February 2024 Pan-STARRS 1 () 4 unusual 38.7 0.92 25 3.2 74.3 albedo: 0.051 4 March 2024 Korea Microlensing Telescope Network-CTIO () 160 cubewano (cold)? 43.0 0.10 1 38.7 47.4 albedo: 0.152 — — 209 centaur 74.8 0.75 8 18.7 130.8 albedo: 0.058 16 March 2024 Cerro Tololo-DECam () 201 other TNO 38.4 0.11 2 34.1 42.7 albedo: 0.13 19 March 2024 Pan-STARRS 1 () 10 centaur 61.7 0.89 31 6.6 116.8 albedo: 0.058 16 March 2024 Cerro Tololo-DECam () 152 SDO 251.2 0.84 16 40.9 461.5 albedo: 0.124 16 March 2024 Cerro Tololo-DECam () 107 SDO 80.6 0.59 6 32.9 128.3 albedo: 0.124 16 March 2024 Cerro Tololo-DECam () 217 twotino 48.1 0.28 8 34.5 61.6 albedo: 0.126 3 April 2024 Cerro Tololo-DECam () 214 other TNO 41.6 0.17 37 34.7 48.5 albedo: 0.13 3 April 2024 Cerro Tololo-DECam () 163 centaur 46.9 0.41 31 27.9 66.0 albedo: 0.058 4 April 2024 ATLAS South Africa, Sutherland () 146 centaur 33.4 0.54 35 15.4 51.4 albedo: 0.058 2 May 2024 Pan-STARRS 1 () 3 damocloid 41.4 0.93 58 3.1 79.8 albedo: 0.048 15 June 2024 Pan-STARRS 2 () 35 centaur 60.2 0.84 146 9.7 110.7 albedo: 0.058 30 July 2024 Purple Mountain Observatory, XuYi Station () 107 centaur 35.8 0.52 19 17.2 54.4 albedo: 0.058 15 August 2024 Pan-STARRS 1 () 37 centaur 87.4 0.93 142 6.6 168.2 albedo: 0.058 3 August 2024 Pan-STARRS 1 () 44 centaur 187.3 0.97 153 6.3 368.4 albedo: 0.058 15 August 2024 Calar Alto-Schmidt () 4 damocloid 92.4 0.97 136 2.9 181.8 albedo: 0.048 27 August 2024 Pan-STARRS 1 () 4 damocloid 255.8 0.99 144 3.1 508.5 albedo: 0.048 11 September 2024 Pan-STARRS 2 () 96 centaur 53.6 0.64 26 19.4 87.8 albedo: 0.058 1 September 2024 Pan-STARRS 2 () 2.3 damocloid 58.2 0.95 133 2.7 113.7 albedo: 0.048 3 October 2024 Pan-STARRS 2 () 42 centaur 47.9 0.77 89 10.9 84.8 albedo: 0.058 8 December 2024 Pan-STARRS 2 () 2.7 damocloid 55.4 0.95 98 2.7 108.1 albedo: 0.048 2 December 2024 Subaru Telescope, Maunakea () 139 other TNO 48.2 0.24 19 36.4 59.9 albedo: 0.13 2 December 2024 Kitt Peak-Bok () 4 centaur 48.1 0.89 29 5.3 91.0 albedo: 0.058 3 December 2024 Subaru Telescope, Maunakea () 251 SDO 69.3 0.49 19 35.3 103.4 albedo: 0.124 3 December 2024 Subaru Telescope, Maunakea () 121 other TNO 47.9 0.29 9 34.2 61.6 albedo: 0.13 4 December 2024 Subaru Telescope, Maunakea () 92 other TNO 45.9 0.18 10 37.5 54.4 binary: 72 km; albedo: 0.13 2 December 2024 Subaru Telescope, Maunakea () 195 centaur 39.9 0.25 12 30.0 49.9 albedo: 0.058
2025 List of unnumbered trans-Neptunian objects: 2025
2026 Designation First Observed (discovered) D (km) Orbital description Remarks Refs Date Observer(Site) Class a e i q Q — — — — 64.6 0.96 36 2.5 126.7 — — — — — 44.2 0.14 53.7 37.9 50.5 — — — — — 49.6 0.64 40 17.9 81.2 —
See also List of unnumbered minor planets List of the brightest Kuiper belt objects List of Solar System objects by greatest aphelion List of Solar System objects most distant from the Sun
References
External links How many dwarf planets are there in the outer solar system?, Michael Brown, Caltech