Plutoid

Sze of the major Trans-Neptunian dwarf planets

Plutoid is an astronomical designation for dwarf planets beyond the orbit of Neptune.

Astronomy

Currently this group in cludes Pluto, Haumea, Makemake, and Eris.
Official astronomy's (IAU) candidates for receiving the status of a plutoid are Quaoar and Sedna.

Table

Name	Type	Date of discovery, Photographic proof (UT), Place	Diameter + Moon(s)	Perihelion q Aphelion Q	Orbital Period	Degree of Perihelion (ca.)
Pluto	Plutoid	18.2.1930 23:00 Flagstaff (AZ)	2.370 km + 1.208 km + ca. 45 km + ca. 35 km + ca. 30 km + ca. 8 km	q Sep 1989 29.658 AU	247.68 a	15°
Quaoar	Cubewano	4.6.2002 5:41:40 Palomar Mountain (CA)	1170 km	Q Sep 2070 45,169 AU q Mar 1927 42,008 AU	285.97 a	11°
Eris	Plutoid/ SDO	21.10.2003 6:25:09 Palomar Mountain (CA)	2.326 km	q Jan 1698 38.540 AU Q Oct 1978 97.557 AU	556,97 a	14°
Sedna	TNO	14.11.2003 6:32:57 Palomar Mountain (CA)	995 km	q Aug 2075 76.361 AU Q 960.782 AU	11.222 a	7°
Haumea	Plutoid	28.12.2004 0:40:40 Observatorio de Sierra Nevada (SPA)	1.150 x 2.200 km + 310 km + 160 km	Q Feb 1991 51.524 AU q Oct 2133 35.159 AU	285,3 a	29°
Makemake	Plutoid	31.3.2005 6:13:30 Palomar Mountain (CA)	1.473 km	q Nov 1879 38,543 AU Q Jun 2034 52,778 AU	308,54 a	17°

Critical Review

Astronomy's classification of Pluto as being both a plutino and a plutoid is rather confusing.
In his chapter "Plutoids, Rutoids, Schmutoids" David Jewitt summarizes : "Big KBOs are best called... Big KBOs. Fussing about with other names may have value to some, but it is not scientific value."

See also

• Plutino
• Trans-Neptunians

Weblinks

• Wikipedia: Plutoid
• How big is Pluto? New Horizons settles decades-long debate (NASA, 2015)
• Plutoid chosen as name for Solar System objects like Pluto - IAU (2008)
• philipsedgwick.com (Plutoids, Eris, Sedna, Centaurs & Kuiper Belt Objects)