Eris (dwarf planet)
Eris
Eris (centre) and Dysnomia (left of centre).
Hubble Space Telescope.
Discovery
Discovered by
M. E. Brown,
C. A. Trujillo,
D. L. Rabinowitz[1]
Discovery date
2005 January 5[2]
Designations
MPC designation
136199 Eris
Alternate name
2003 UB313[3]
Minor planet
category
dwarf planet,
TNO,
plutoid,
and SDO[4][5]
Adjective
Eridian
Orbital characteristics[6]
Epoch March 6, 2006
(JD 2453800.5)[7]
Aphelion
97.56 AU
14.60 × 109 km
Perihelion
37.77 AU
5.65 × 109 km
Semi-major axis
67.67 AU
10.12 × 109 km
Eccentricity
0.441 77
Orbital period
203,600 days
557 years
Average
orbital speed
3.436 km/s
Mean anomaly
197.634 27°
Inclination
44.187°
Longitude of
ascending node
35.869 6°
Argument of
perihelion
151.430 5°
Satellites
1
Physical characteristics
Mean radius
1300+200−100 km[8]
Mass
(1.67±0.02) × 1022
kg[9]
Equatorial
surface gravity
~0.8 m/s²
Sidereal rotation
period
> 8 h?
Albedo
0.86 ± 0.07
Surface temp.
(approx)
min mean max
30 K 42.5 K 55 K
Apparent magnitude
18.7[10]
Absolute magnitude
(H)
−1.12 ± 0.01[6]
Angular diameter
40 milli-arcsec[11]
Eris (pronounced /ˈɪərɨs/, or /ˈɛrɨs/ as in
Greek Έρις),[a] formal designation 136199
Eris, is the largest known dwarf planet in the
Solar System and the ninth-largest body
known to orbit the Sun directly. It is approx-
imately 2,500 kilometres in diameter and
27% more massive than Pluto.[12][9]
Eris was first spotted in January 2005 by a
Palomar Observatory-based team led by Mike
Brown, and its identity verified later that
year. It is a trans-Neptunian object (TNO)
native to a region of space beyond the Kuiper
belt known as the scattered disc. Eris has
one moon, Dysnomia; recent observations
have found no evidence of further satellites.
The current distance from the Sun is 96.7
AU,[10] roughly three times that of Pluto.
With the exception of some comets the pair
From Wikipedia, the free encyclopedia
Eris (dwarf planet)
1
are the most distant known natural objects in
the Solar System.[2]
Because Eris is larger than Pluto, its dis-
coverers and NASA called