Eris (dwarf planet)

This article is about the dwarf planet. For the asteroid with a similar name, see 433 Eros. For other uses, see Eris.

136199 Eris
Low-resolution image of Eris and Dysnomia as imaged by the Hubble Space Telescope, August 2006
Discovery
Discovered by
Discovery dateJanuary 5, 2005[2]
Designations
(136199) Eris
Pronunciation/ˈɛrɪs/,[3][4] /ˈɪərɪs/[5][4]
Named after
Ἔρις Eris
2003 UB313[6]
Xena (nickname)
AdjectivesEridian /ɛˈrɪdiən/[9][10]
Symbol⯰ (mostly astrological)
Orbital characteristics[6]
Epoch May 31, 2020
(JD 2459000.5)
Earliest precovery dateSeptember 3, 1954
Aphelion97.457 AU (14.579 Tm)
Perihelion38.271 AU (5.725 Tm)
67.864 AU (10.152 Tm)
Eccentricity0.43607
559.07 yr (204,199 d)
3.434 km/s
205.989°
0° 0m 6.307s / day
Inclination44.040°
35.951°
≈ December 1, 2257[11]
±11 days
151.639°
Known satellites1 (Dysnomia)
Physical characteristics
2326±12 km
1163±6 km[12][13]
(1.70±0.02)×107 km2[a]
Volume(6.59±0.10)×109 km3[a]
Mass
  • (1.6466±0.0085)×1022 kg (system)[14]
  • (1.638±0.014)×1022 kg (Eris only)[b]
  • 0.0027 Earths; 0.22 Moons
Mean density
2.43±0.05 g/cm3[14]
Equatorial surface gravity
0.82±0.02 m/s2
0.084±0.002 g[c]
Equatorial escape velocity
1.38 ± 0.01 km/s[c]
15.786 d (synchronous)[15]
≈ 78.3° to orbit (assumed)[d][16]
≈ 61.6° to ecliptic (assumed)[d][e]
0.96+0.09
−0.04 [sic] geometric[12]
0.99+0.01
−0.09 Bond[17]
Surface temp. min mean max
(approx) 30 K 42 K[18] 56 K
B−V=0.78, V−R=0.45[19]
18.7[20]
–1.21[6]
34.4±1.4 milli-arcsec[21]

Eris (minor-planet designation: 136199 Eris) is the most massive and second-largest known dwarf planet in the Solar System.[22] It is a trans-Neptunian object (TNO) in the scattered disk and has a high-eccentricity orbit. Eris was discovered in January 2005 by a Palomar Observatory–based team led by Mike Brown and verified later that year. It was named in September 2006 after the Greco–Roman goddess of strife and discord. Eris is the ninth-most massive known object orbiting the Sun and the sixteenth-most massive overall in the Solar System (counting moons). It is also the largest known object in the solar system that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometres (1,445 ± 7 mi) in diameter;[12] its mass is 0.28% that of the Earth and 27% greater than that of Pluto,[23][24] although Pluto is slightly larger by volume.[25] Both Eris and Pluto have a surface area that is comparable to that of Russia or South America.

Eris has one large known moon, Dysnomia. In February 2016, Eris's distance from the Sun was 96.3 AU (14.41 billion km; 8.95 billion mi),[20] more than three times that of Neptune or Pluto. With the exception of long-period comets, Eris and Dysnomia were the most distant known natural objects in the Solar System until the discovery of 2018 AG37 and 2018 VG18 in 2018.[20]

Because Eris appeared to be larger than Pluto, NASA initially described it as the Solar System's tenth planet. This, along with the prospect of other objects of similar size being discovered in the future, motivated the International Astronomical Union (IAU) to define the term planet for the first time. Under the IAU definition approved on August 24, 2006, Eris, Pluto and Ceres are "dwarf planets",[26] reducing the number of known planets in the Solar System to eight, the same as before Pluto's discovery in 1930. Observations of a stellar occultation by Eris in 2010 showed that it was slightly smaller than Pluto,[27][28] which was measured by New Horizons as having a mean diameter of 2,377 ± 4 kilometres (1,477 ± 2 mi) in July 2015.[29][30]

  1. ^ Cite error: The named reference discovery was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference New Planet was invoked but never defined (see the help page).
  3. ^ "Eris". Lexico UK English Dictionary. Oxford University Press. Archived from the original on July 31, 2020.
    "Eris". Merriam-Webster.com Dictionary. Merriam-Webster.
  4. ^ a b "Eris". Dictionary.com Unabridged (Online). n.d.
  5. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  6. ^ a b c Cite error: The named reference jpldata was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference MPC was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Buie2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Morrison was invoked but never defined (see the help page).
  10. ^ Ian Douglas (2013) Semper Human
  11. ^ Cite error: The named reference Horizons2257 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference sicardy was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Beatty2010-NewScientist was invoked but never defined (see the help page).
  14. ^ a b c d Cite error: The named reference Holler2021 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Szakats2022 was invoked but never defined (see the help page).
  16. ^ a b Cite error: The named reference Holler2018 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Verbiscer2022 was invoked but never defined (see the help page).
  18. ^ "Eris Facts". Space Facts. Archived from the original on May 28, 2023. Retrieved May 26, 2021.
  19. ^ Cite error: The named reference Snodgrass et al. 2010 was invoked but never defined (see the help page).
  20. ^ a b c Cite error: The named reference AstDys was invoked but never defined (see the help page).
  21. ^ Cite error: The named reference Brown-2003-UB313 was invoked but never defined (see the help page).
  22. ^ "Dwarf Planets". Canadian Space Agency. March 12, 2020. Archived from the original on November 26, 2020. Retrieved January 1, 2023.
  23. ^ Cite error: The named reference Brown Schaller 2007 was invoked but never defined (see the help page).
  24. ^ Cite error: The named reference 070614_eris_mass was invoked but never defined (see the help page).
  25. ^ Cite error: The named reference NASA Pluto larger 2015 was invoked but never defined (see the help page).
  26. ^ Cite error: The named reference IAUPressRelease2006 was invoked but never defined (see the help page).
  27. ^ Cite error: The named reference Brown2010-occult was invoked but never defined (see the help page).
  28. ^ Cite error: The named reference Brown2010-Plutosize was invoked but never defined (see the help page).
  29. ^ "How Big Is Pluto? New Horizons Settles Decades-Long Debate". NASA. 2015. Archived from the original on July 13, 2015. Retrieved July 13, 2015.
  30. ^ Stern, S. A.; Grundy, W.; et al. (September 2018). "The Pluto System After New Horizons". Annual Review of Astronomy and Astrophysics. 56: 357–392. arXiv:1712.05669. Bibcode:2018ARA&A..56..357S. doi:10.1146/annurev-astro-081817-051935. S2CID 119072504. Archived from the original on October 21, 2022. Retrieved April 5, 2022.


Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).