Difference between revisions of "Eris"

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: ''This article is about the [[Dwarf Planet]] named Eris. For the classical goddess, see [[Eris (mythology)]]. For any other use, see [[Eris (disambiguation)]].
 
{{Planet|image=Eris and Dysnomia.jpg
 
{{Planet|image=Eris and Dysnomia.jpg
 
|date=October 21, 2003<ref name=IAU1>"[http://www.cfa.harvard.edu/iau/lists/NumberedMPs.html Discovery Circumstances: Numbered Minor Planets]." [[International Astronomical Union]], Minor Planet Center, May 1, 2007. Accessed May 15, 2008.</ref>
 
|date=October 21, 2003<ref name=IAU1>"[http://www.cfa.harvard.edu/iau/lists/NumberedMPs.html Discovery Circumstances: Numbered Minor Planets]." [[International Astronomical Union]], Minor Planet Center, May 1, 2007. Accessed May 15, 2008.</ref>
|discname=Michael E. Brown<ref name=IAU1/><ref name=usgs>"[http://planetarynames.wr.usgs.gov/append7.html Gazetteer of Planetary Nomenclature: Planetary Body Names and Discoverers]." US Geological Survey, Jennifer Blue, ed. March 31, 2008. Accessed April 17, 2008.</ref><ref name=Brown2>Brown, M.E., Van Dam, M. A., Bouchez, A. H., Le Mignant, D., ''et al''. "[http://arxiv.org/pdf/astro-ph/0510029 Satellites of the Largest Kuiper Belt Objects]." ''Astrophys. J. Lett.'' 639(L43), October 3, 2005. <arXiv:astro-ph/0510029.> Accessed May 15, 2008.</ref>
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|discname=Michael E. Brown<ref name=IAU1/><ref name=usgs>"[http://planetarynames.wr.usgs.gov/append7.html Gazetteer of Planetary Nomenclature: Planetary Body Names and Discoverers]." US Geological Survey, Jennifer Blue, ed. March 31, 2008. Accessed April 17, 2008.</ref><ref name=Brown2>Brown, M.E., Van Dam, M. A., Bouchez, A. H., Le Mignant, D., ''et al''. "[https://arxiv.org/pdf/astro-ph/0510029 Satellites of the Largest Kuiper Belt Objects]." ''Astrophys. J. Lett.'' 639(L43), October 3, 2005. <arXiv:astro-ph/0510029.> Accessed May 15, 2008.</ref>
 
|origname=Greek goddess of discord<ref name=usgs/>
 
|origname=Greek goddess of discord<ref name=usgs/>
 
|primary=Sun
 
|primary=Sun
|order=11
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|order=12
 
|periapsis=37.93 AU<ref name=johnston>Johnston, William Robert. "[http://www.johnstonsarchive.net/astro/astmoons/am-136199.html Entry for 136199 Eris and Dysnomia]." Johnston Archive, August 21, 2007. Accessed May 15, 2008.</ref>
 
|periapsis=37.93 AU<ref name=johnston>Johnston, William Robert. "[http://www.johnstonsarchive.net/astro/astmoons/am-136199.html Entry for 136199 Eris and Dysnomia]." Johnston Archive, August 21, 2007. Accessed May 15, 2008.</ref>
 
|apoapsis=97.53 AU<ref name=johnston/>
 
|apoapsis=97.53 AU<ref name=johnston/>
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|reference=the ecliptic
 
|reference=the ecliptic
 
|siderealday=8 h
 
|siderealday=8 h
|mass=1.66 * 10<sup>22</sup> kg<ref name=johnston/><ref name=Brown1>Brown, Michael E., and Schaller, Emily L. "[http://www.sciencemag.org/cgi/content/abstract/316/5831/1585 The Mass of Dwarf Planet Eris]." ''Science'', 316(5831):1585, June 15, 2007. <doi:10.1126/science.1139415> Accessed May 15, 2008.</ref><ref name=reitan>Reitan, Kari. "[http://www.nasa.gov/mission_pages/hubble/news/eris.html Astronomers Measure Mass of Largest Dwarf Planet]." Space Telescope Science Institute, [[National Aeronautics and Space Administration]], June 14, 2007. Accessed January 21, 2008.</ref>
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|mass=1.66 * 10<sup>22</sup> kg<ref name=johnston/><ref name=Brown1>Brown, Michael E., and Schaller, Emily L. "[http://www.sciencemag.org/cgi/content/abstract/316/5831/1585 The Mass of Dwarf Planet Eris]." ''Science'', 316(5831):1585, June 15, 2007. <doi:10.1126/science.1139415> Accessed May 15, 2008.</ref><ref name=reitan>Reitan, Kari. "[https://www.nasa.gov/mission_pages/hubble/news/eris.html Astronomers Measure Mass of Largest Dwarf Planet]." Space Telescope Science Institute, [[National Aeronautics and Space Administration]], June 14, 2007. Accessed January 21, 2008.</ref>
 
|density=2,260 kg/m³<ref name=johnston/>
 
|density=2,260 kg/m³<ref name=johnston/>
 
|surfacegrav=0.6554 m/s²<ref name=calc/>
 
|surfacegrav=0.6554 m/s²<ref name=calc/>
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|color=white to light gray
 
|color=white to light gray
 
|albedo=0.87<ref name=johnston/>
 
|albedo=0.87<ref name=johnston/>
}}'''Eris''', alias '''Xena''', alias '''2003 UB<sub>313</sub>''', the largest of all [[dwarf planet]]s, is named for the Greek goddess of discord and strife. Considering the debate that the discovery of this object provoked, the name is probably quite apt.
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}}'''Eris''', also known as '''Xena''', also known as '''2003 UB<sub>313</sub>''', the largest of all [[dwarf planet]]s (also classified as a [[Dwarf Planet#Plutoids|plutoid]]), is named for the Greek goddess of discord and strife. Considering the debate that the discovery of this object provoked, the name is probably quite apt.
  
 
== Discovery, Naming, and Debate ==
 
== Discovery, Naming, and Debate ==
 
Eris was first photographed on October 21, 2003, but was at first too slow-moving for the Palomar Observatory image-analytic software to detect. Later, [[Michael E. Brown]], [[Chad Trujillo]], and [[David Rabinowitz]] ordered  re-analysis of the images with greater sensitivity. They soon realized that the images depicted a new object, and announced their findings on January 5, 2005.
 
Eris was first photographed on October 21, 2003, but was at first too slow-moving for the Palomar Observatory image-analytic software to detect. Later, [[Michael E. Brown]], [[Chad Trujillo]], and [[David Rabinowitz]] ordered  re-analysis of the images with greater sensitivity. They soon realized that the images depicted a new object, and announced their findings on January 5, 2005.
  
The initial name for the new object was Xena, the title character in an [[United States|American]] [[television]] action-adventure dramatic series,<ref>The character is supposed to be a princess from a tribe of warriors, either Argive or closely allied with them, in the days of the Mycenean civilization, and a contemporary of, and occasional rival to, Hercules. No historical warrant exists for the existence of such a person or even for a classical poem mentioning that name.</ref> and also a name beginning with X, in keeping with the suspicion that this object was the long-sought "Planet X." But the announcement of Eris' discovery on July 29, 2005 presented the [[International Astronomical Union]] with an embarrassing problem.<ref name=Hamilton>Hamilton, Calvin J. "[http://www.solarviews.com/eng/eris.htm Entry for 'Eris']." ''Views of the Solar System'', 2007. Accessed January 21, 2008.</ref> Other observations<ref name=Ingham>Ingham, Richard. "[http://www.abc.net.au/science/news/stories/s1560563.htm 'Tenth planet' Xena bigger than Pluto]." Agence France-Presse, quoted by Australian Broadcasting Corporation, February 2, 2006. Accessed May 15, 2008.</ref><ref name=solstation>[http://www.solstation.com/stars/UB313.htm Eris (2003 UB<sub>313</sub>) and Dysnomia]. Accessed January 22, 2008.</ref> had already suggested that 2003 UB<sub>313</sub> might be more massive even than [[Pluto]], then considered the ninth [[planet]] in the [[solar system]]. Because planets and Kuiper-Belt objects have different naming conventions, and because [[scatter disk]] objects had ''no'' naming convention at the time, the names for these two objects remained unofficial.<ref name=Tytell>Tytell, David. "[http://www.skyandtelescope.com/news/home/3916126.html All Hail Eris and Dysnomia]." ''Sky and Telescope'', September 14, 2006. Accessed May 15, 2008.</ref>
+
The initial name for the new object was Xena, the title character in an [[United States|American]] [[television]] action-adventure dramatic series,<ref>The character is supposed to be a princess from a tribe of warriors, either Argive or closely allied with them, in the days of the Mycenean civilization, and a contemporary of, and occasional rival to, Hercules. No historical warrant exists for the existence of such a person or even for a classical poem mentioning that name.</ref> and also a name beginning with X, in keeping with the suspicion that this object was the long-sought "Planet X." The object also had a satellite, which the discoverers tentatively named Gabrielle, after the supporting character in that dramatic series.
 +
 
 +
The announcement of Eris' discovery on July 29, 2005 presented the [[International Astronomical Union]] with an embarrassing problem.<ref name=Hamilton>Hamilton, Calvin J. "[http://www.solarviews.com/eng/eris.htm Entry for 'Eris']." ''Views of the Solar System'', 2007. Accessed January 21, 2008.</ref> Other observations, specifically of the period and orbital characteristics of the satellite,<ref name=Ingham>Ingham, Richard. "[http://www.abc.net.au/science/news/stories/s1560563.htm 'Tenth planet' Xena bigger than Pluto]." Agence France-Presse, quoted by Australian Broadcasting Corporation, February 2, 2006. Accessed May 15, 2008.</ref><ref name=solstation>[http://www.solstation.com/stars/UB313.htm Eris (2003 UB<sub>313</sub>) and Dysnomia]. Accessed January 22, 2008.</ref> had already suggested that 2003 UB<sub>313</sub> might be more massive even than [[Pluto]], then considered the ninth [[planet]] in the [[solar system]]. Because planets and Kuiper-Belt objects have different naming conventions, and because [[scattered disk]] objects had ''no'' naming convention at the time, the names for the new primary and satellite remained unofficial.<ref name=Tytell>Tytell, David. "[http://www.skyandtelescope.com/news/home/3916126.html All Hail Eris and Dysnomia]." ''Sky and Telescope'', September 14, 2006. Accessed May 15, 2008.</ref>
 +
 
 +
Finally the [[International Astronomical Union]] arbitrarily declared<ref>"[http://www.iau.org/iau0602.423.0.html IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting]," ''International Astronomical Union'', 2005. Accessed January 14, 2008.</ref> that Pluto and 2003 UB<sub>313</sub> were not planets, but belonged to a new category called [[dwarf planet]]s. Then on September 6, 2006, Mike Brown and his team<ref name=Brown4>Brown, Mike. "[http://www.gps.caltech.edu/%7Embrown/planetlila/index.html The discovery of Eris, the largest known dwarf planet]." California Institute of Technology. Accessed January 22, 2008.</ref> recognized that the name "Xena" was inappropriate for 2003 UB<sub>313</sub> and suggested to the IAU that they name it Eris, after the Greek goddess of discord and strife. They also suggested that the IAU name the satellite Dysnomia, for the Greek goddess of lawlessness and daughter of Eris.<ref>Dysnomia, meaning "lawlessness," is also a play on the name of the American actress who portrayed Xena, Lucy Lawless.</ref> Four days later, the IAU officially named the primary Eris and named its satellite Dysnomia.<ref name=IAU2>[http://cfa-www.harvard.edu/iau/special/08747.pdf IAU Circular No. 8747], International Astronomical Union, September 10, 2006. Accessed May 15, 2008.</ref>
 +
 
 +
== [[Earth]] and [[Mars]] as [[dwarf planet|dwarf planets]] under the current [[International Astronomical Union]] definition ==
 +
 
 +
According to Number 1 (c) and 2 (c) of the [[International Astronomical Union|IAU]] definition, also [[Earth]] and [[Mars]] wouldn't be planets because they haven't "cleared" their orbits as several asteroids are in their respective orbits, these asteroids are also called "quasi-moons" of Earth and Mars. The IAU precluded this possibility by arbitrarily listing the earth and mars as planets in spite of the current definition (see the quote in the section [[Pluto#the_dwarf_planet_controversy|The dwarf planet controversy]] where it says ''"<sup>1</sup>The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune."'').
 +
This, however, calls into question the "''scientific''" basis of downgrading Pluto to a dwarf plant as this conflicting standard(of confirming [[earth]] and [[mars]] as planets while classifying Pluto as a dwarf planet) suggests it is merely the '''''opinion''''' of the IAU that Pluto is not a planet <ref>https://www.iau.org/static/resolutions/Resolution_GA26-5-6.pdf ''International Astronomical Union'', 2005. Accessed February 9, 2022</ref>
  
Finally the [[International Astronomical Union]] declared<ref>"[http://www.iau.org/iau0602.423.0.html IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting]," ''International Astronomical Union'', 2005. Accessed January 14, 2008.</ref> that Pluto and 2003 UB<sub>313</sub> were not planets, but belonged to a new category called [[dwarf planet]]s. Then on September 6, 2006, Mike Brown and his team<ref name=Brown4>Brown, Mike. "[http://www.gps.caltech.edu/%7Embrown/planetlila/index.html The discovery of Eris, the largest known dwarf planet]." California Institute of Technology. Accessed January 22, 2008.</ref> recognized that the name "Xena" was inappropriate for 2003 UB<sub>313</sub> and suggested to the IAU that they name it Eris, after the Greek goddess of discord and strife. They also suggested that the IAU name the satellite Dysnomia, for the Greek goddess of lawlessness and daughter of Eris.<ref>Dysnomia, meaning "lawlessness," is also a play on the name of the American actress who portrayed Xena, Lucy Lawless.</ref> Four days later, the IAU oficially named the primary Eris and named its satellite Dysnomia.<ref name=IAU2>[http://cfa-www.harvard.edu/iau/special/08747.pdf IAU Circular No. 8747], International Astronomical Union, September 10, 2006. Accessed May 15, 2008.</ref>
 
  
 
== Orbital characteristics ==
 
== Orbital characteristics ==
At 67.7 AU from the [[Sun]], it is the most distant object yet discovered that has the [[Sun]] for a primary. At aphelion, it is far beyond the [[Kuiper belt]] and in what is known as the [[Scatter Disk]] of the [[solar system]]. Because Eris is so distant from [[Earth]] (currently near [[Apsis|aphelion]] and hence three times more distant than is Pluto as of 2008), it has a very long sidereal year of 557 Julian years. Its synodic year is very nearly the same as an [[Earth]] year.
+
At 67.7 AU from the [[Sun]], it is the most distant object yet discovered that has the [[Sun]] for a primary. At aphelion, it is far beyond the [[Kuiper belt]] and in what is known as the [[scattered disk]] of the [[solar system]]. Because Eris is so distant from [[Earth]] (currently near [[Apsis|aphelion]] and hence three times more distant than is Pluto as of 2008), it has a very long sidereal year of 557 Julian years. Its synodic year is very nearly the same as an [[Earth]] year.
  
 
== Surface and atmosphere ==
 
== Surface and atmosphere ==
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Yet Eris is the second most reflective body in the entire solar system, reflecting about 86% of the incident sunlight. Eris is also uniformly white on its surface, whereas Pluto is a mottled brown. The discoverers believe that this is due entirely to Eris' present far-flung position (near aphelion), and point out that Eris' orbit is the most eccentric orbit of any satellite of the [[Sun]], except for [[comet]]s.
 
Yet Eris is the second most reflective body in the entire solar system, reflecting about 86% of the incident sunlight. Eris is also uniformly white on its surface, whereas Pluto is a mottled brown. The discoverers believe that this is due entirely to Eris' present far-flung position (near aphelion), and point out that Eris' orbit is the most eccentric orbit of any satellite of the [[Sun]], except for [[comet]]s.
 +
 +
== Implications for Other Trans-Neptunian Objects ==
 +
Brown ''et al.'' noted<ref name=Brown2/> in 2005 that Eris, Dysnomia's primary, is one of three of the four brightest Kuiper belt objects that have satellites. (The other two are [[Pluto]] and 2003 EL<sub>61</sub>.) The fourth, 2005 FY<sub>9</sub>, has no satellite that Earth-based telescopes can presently detect. Most Kuiper belt objects ''do not'' have satellites, and that three of the four brightest should have satellites suggests that their origins were significantly different from those of other Kuiper belt objects.
 +
 +
== Problem for uniformitarian theories ==
 +
Brown states<ref name=Brown1/> that the near-circular orbit of Dysnomia about Eris actually is consistent with Dysnomia's origin as the result of a collision between Eris and another object. But no astronomer has ever explained how such a collision would leave an object in a nearly circular orbit about its primary.
  
 
== Satellites ==
 
== Satellites ==
 
Eris has one known satellite, a tiny moon called [[Dysnomia]]. In classical [[mythology]], Dysnomia is the name given to Eris' daughter, who is a symbol of actual lawlessness.
 
Eris has one known satellite, a tiny moon called [[Dysnomia]]. In classical [[mythology]], Dysnomia is the name given to Eris' daughter, who is a symbol of actual lawlessness.
 +
 +
== Observation and exploration ==
 +
The [[Hubble Space Telescope]] and the Keck Observatory are the first two telescopes to observe the Eridian system. No deep-space missions are planned.
 +
 +
== See Also ==
 +
* [[Pluto#the_dwarf_planet_controversy|The Dwarf Planet Controversy]]
  
 
== References ==
 
== References ==

Latest revision as of 03:25, February 10, 2022

This article is about the Dwarf Planet named Eris. For the classical goddess, see Eris (mythology). For any other use, see Eris (disambiguation).
Eris
Eris and Dysnomia.jpg
Date of discovery October 21, 2003[1]
Name of discoverer Michael E. Brown[1][2][3]
Name origin Greek goddess of discord[2]
Orbital characteristics
Primary Sun
Order from primary 12
Perihelion 37.93 AU[4]
Aphelion 97.53 AU[4]
Semi-major axis 67.732 AU[4]
Titius-Bode prediction 154 AU[5]
Orbital eccentricity 0.4400[4]
Sidereal year 557.4 a[4]
Avg. orbital speed 3.436 km/s
Inclination 44.1595°[4] to the ecliptic
Rotational characteristics
Sidereal day 8 h
Physical characteristics
Mass 1.66 * 1022 kg[4][6][7]
Density 2,260 kg/m³[4]
Mean radius 1,300 km[8]
Surface gravity 0.6554 m/s²[5]
Escape speed 1.305 km/s[5]
Surface area 21,237,166 km²[5]
Minimum temperature 30 K
Mean temperature 42.5 K
Maximum temperature 55 K
Number of moons 1
Color white to light gray
Albedo 0.87[4]
Eris, also known as Xena, also known as 2003 UB313, the largest of all dwarf planets (also classified as a plutoid), is named for the Greek goddess of discord and strife. Considering the debate that the discovery of this object provoked, the name is probably quite apt.

Discovery, Naming, and Debate

Eris was first photographed on October 21, 2003, but was at first too slow-moving for the Palomar Observatory image-analytic software to detect. Later, Michael E. Brown, Chad Trujillo, and David Rabinowitz ordered re-analysis of the images with greater sensitivity. They soon realized that the images depicted a new object, and announced their findings on January 5, 2005.

The initial name for the new object was Xena, the title character in an American television action-adventure dramatic series,[9] and also a name beginning with X, in keeping with the suspicion that this object was the long-sought "Planet X." The object also had a satellite, which the discoverers tentatively named Gabrielle, after the supporting character in that dramatic series.

The announcement of Eris' discovery on July 29, 2005 presented the International Astronomical Union with an embarrassing problem.[10] Other observations, specifically of the period and orbital characteristics of the satellite,[11][12] had already suggested that 2003 UB313 might be more massive even than Pluto, then considered the ninth planet in the solar system. Because planets and Kuiper-Belt objects have different naming conventions, and because scattered disk objects had no naming convention at the time, the names for the new primary and satellite remained unofficial.[13]

Finally the International Astronomical Union arbitrarily declared[14] that Pluto and 2003 UB313 were not planets, but belonged to a new category called dwarf planets. Then on September 6, 2006, Mike Brown and his team[15] recognized that the name "Xena" was inappropriate for 2003 UB313 and suggested to the IAU that they name it Eris, after the Greek goddess of discord and strife. They also suggested that the IAU name the satellite Dysnomia, for the Greek goddess of lawlessness and daughter of Eris.[16] Four days later, the IAU officially named the primary Eris and named its satellite Dysnomia.[17]

Earth and Mars as dwarf planets under the current International Astronomical Union definition

According to Number 1 (c) and 2 (c) of the IAU definition, also Earth and Mars wouldn't be planets because they haven't "cleared" their orbits as several asteroids are in their respective orbits, these asteroids are also called "quasi-moons" of Earth and Mars. The IAU precluded this possibility by arbitrarily listing the earth and mars as planets in spite of the current definition (see the quote in the section The dwarf planet controversy where it says "1The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune."). This, however, calls into question the "scientific" basis of downgrading Pluto to a dwarf plant as this conflicting standard(of confirming earth and mars as planets while classifying Pluto as a dwarf planet) suggests it is merely the opinion of the IAU that Pluto is not a planet [18]


Orbital characteristics

At 67.7 AU from the Sun, it is the most distant object yet discovered that has the Sun for a primary. At aphelion, it is far beyond the Kuiper belt and in what is known as the scattered disk of the solar system. Because Eris is so distant from Earth (currently near aphelion and hence three times more distant than is Pluto as of 2008), it has a very long sidereal year of 557 Julian years. Its synodic year is very nearly the same as an Earth year.

Surface and atmosphere

Near infrared spectrum of dwarf planet Eris, taken with the Gemini 8 m telescope.
Infrared spectroscopic scans of Eris reveal an infrared reflectance spectrum remarkably like that of Pluto, which is known to have a layer of methane on its surface. From this, the discovery team concludes that Eris is surfaced with solid frozen methane, with rock and water ice beneath.

Yet Eris is the second most reflective body in the entire solar system, reflecting about 86% of the incident sunlight. Eris is also uniformly white on its surface, whereas Pluto is a mottled brown. The discoverers believe that this is due entirely to Eris' present far-flung position (near aphelion), and point out that Eris' orbit is the most eccentric orbit of any satellite of the Sun, except for comets.

Implications for Other Trans-Neptunian Objects

Brown et al. noted[3] in 2005 that Eris, Dysnomia's primary, is one of three of the four brightest Kuiper belt objects that have satellites. (The other two are Pluto and 2003 EL61.) The fourth, 2005 FY9, has no satellite that Earth-based telescopes can presently detect. Most Kuiper belt objects do not have satellites, and that three of the four brightest should have satellites suggests that their origins were significantly different from those of other Kuiper belt objects.

Problem for uniformitarian theories

Brown states[6] that the near-circular orbit of Dysnomia about Eris actually is consistent with Dysnomia's origin as the result of a collision between Eris and another object. But no astronomer has ever explained how such a collision would leave an object in a nearly circular orbit about its primary.

Satellites

Eris has one known satellite, a tiny moon called Dysnomia. In classical mythology, Dysnomia is the name given to Eris' daughter, who is a symbol of actual lawlessness.

Observation and exploration

The Hubble Space Telescope and the Keck Observatory are the first two telescopes to observe the Eridian system. No deep-space missions are planned.

See Also

References

  1. 1.0 1.1 "Discovery Circumstances: Numbered Minor Planets." International Astronomical Union, Minor Planet Center, May 1, 2007. Accessed May 15, 2008.
  2. 2.0 2.1 "Gazetteer of Planetary Nomenclature: Planetary Body Names and Discoverers." US Geological Survey, Jennifer Blue, ed. March 31, 2008. Accessed April 17, 2008.
  3. 3.0 3.1 Brown, M.E., Van Dam, M. A., Bouchez, A. H., Le Mignant, D., et al. "Satellites of the Largest Kuiper Belt Objects." Astrophys. J. Lett. 639(L43), October 3, 2005. <arXiv:astro-ph/0510029.> Accessed May 15, 2008.
  4. 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Johnston, William Robert. "Entry for 136199 Eris and Dysnomia." Johnston Archive, August 21, 2007. Accessed May 15, 2008.
  5. 5.0 5.1 5.2 5.3 Calculated
  6. 6.0 6.1 Brown, Michael E., and Schaller, Emily L. "The Mass of Dwarf Planet Eris." Science, 316(5831):1585, June 15, 2007. <doi:10.1126/science.1139415> Accessed May 15, 2008.
  7. Reitan, Kari. "Astronomers Measure Mass of Largest Dwarf Planet." Space Telescope Science Institute, National Aeronautics and Space Administration, June 14, 2007. Accessed January 21, 2008.
  8. "Comment on the recent Hubble Space Telescope size measurement of 2003 UB313 by Brown et al." Max Planck Institut für Radioastronomie, April 13, 2006. Accessed May 15, 2008.
  9. The character is supposed to be a princess from a tribe of warriors, either Argive or closely allied with them, in the days of the Mycenean civilization, and a contemporary of, and occasional rival to, Hercules. No historical warrant exists for the existence of such a person or even for a classical poem mentioning that name.
  10. Hamilton, Calvin J. "Entry for 'Eris'." Views of the Solar System, 2007. Accessed January 21, 2008.
  11. Ingham, Richard. "'Tenth planet' Xena bigger than Pluto." Agence France-Presse, quoted by Australian Broadcasting Corporation, February 2, 2006. Accessed May 15, 2008.
  12. Eris (2003 UB313) and Dysnomia. Accessed January 22, 2008.
  13. Tytell, David. "All Hail Eris and Dysnomia." Sky and Telescope, September 14, 2006. Accessed May 15, 2008.
  14. "IAU0602: the Final IAU Resolution on the Definition of 'Planet' Ready for Voting," International Astronomical Union, 2005. Accessed January 14, 2008.
  15. Brown, Mike. "The discovery of Eris, the largest known dwarf planet." California Institute of Technology. Accessed January 22, 2008.
  16. Dysnomia, meaning "lawlessness," is also a play on the name of the American actress who portrayed Xena, Lucy Lawless.
  17. IAU Circular No. 8747, International Astronomical Union, September 10, 2006. Accessed May 15, 2008.
  18. https://www.iau.org/static/resolutions/Resolution_GA26-5-6.pdf International Astronomical Union, 2005. Accessed February 9, 2022