90482 Orcus

A dwarf planet in kuiper belt

90482 Orcus, originally known by the provisional designation 2004 DW, is a Kuiper belt object (KBO). It is also a dwarf planet. It was found by Michael Brown, Chad Trujillo and David Rabinowitz on February 17, 2004. It was also seen in pictures from November 8, 1951. Like Pluto it is in orbital resonance with Neptune but it stays on the opposite side of the Sun from Pluto.

90482 Orcus
Orcus nasa.jpg
Discovered byM. Brown,
C. Trujillo,
D. Rabinowitz
Discovery dateFebruary 17, 2004
2004 DW
Orbital characteristics
Epoch November 30, 2008 (JD 2 454 800)
Aphelion7 188.17 Gm (48.05 AU)
Perihelion4 535.80 Gm (30.32 AU)
5 862.44 Gm (39.188 AU)
Eccentricity0.226 18
89 606 d (245.33 yr)
4.68 km/s
Known satellites1 (92-432 km)
Physical characteristics
Dimensions946.3 +74.1
km (diameter)[2]
Mass~7.5×1020 kg
Mean density
~1.5 g/cm³ (assumed)
~0.2 m/s²
~0.44 km/s
Albedo19.75 +3.40
Temperature~45 K
Spectral type
B-V=0.68; V-R=0.37 [4]
19.1 (opposition)[5]


A moon of Orcus was found on 22 February 2007.[7]

The satellite was found at 0.25 arcsec from Orcus with magnitude difference of 2.7.[8] Assuming an albedo similar to that of the primary, the magnitude suggests a diameter of about 220 km. It is thought to be a smaller KBO that was captured.

Other websitesEdit


  1. Buie, Marc W. (2007-12-22). "Orbit Fit and Astrometric record for 90482". SwRI (Space Science Department). Archived from the original on 2012-02-08. Retrieved 2008-09-19.
  2. Stansberry, J.; Grundy, W.; Brown, M.;; et al. (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". Cite journal requires |journal= (help)CS1 maint: extra punctuation (link) CS1 maint: multiple names: authors list (link)
  3. "Overlooked dwarf planet candidates". BBC. 2008-02-19. Retrieved 2008-07-25.
  4. Tegler, Stephen C. (2006-01-26). "Kuiper Belt Object Magnitudes and Surface Colors". Archived from the original on 2007-11-16. Retrieved 2006-11-05.
  5. "HORIZONS Web-Interface". JPL Solar System Dynamics. Archived from the original on 2012-02-08. Retrieved 2008-07-02.
  6. "JPL Small-Body Database Browser: 90482 Orcus (2004 DW)". 2008-02-10. Archived from the original on 2012-02-08. Retrieved 2008-07-02.
  7. "(90482) Orcus and Vanth". Archived from the original on 2012-02-08. Retrieved 2009-02-27.CS1 maint: bot: original URL status unknown (link)
  8. Distant EKO The Kuiper Belt Electronic newsletter, March 2007