Makemake
![]() Artist's conception of Makemake, by Ann Feild (Space Telescope Science Institute) | |
Discovery | |
---|---|
Discovered by | Michael E. Brown, Chad Trujillo, David Rabinowitz |
Discovery date | March 31 2005 |
Designations | |
Designation | (136472) Makemake |
2005 FY9 | |
TNO | |
Orbital characteristics[1][2] | |
Epoch January 28 1955 (JD 2435135.5) | |
Aphelion | 7,939.7 Gm (53.074 AU) |
Perihelion | 5,760.8 Gm (38.509 AU) |
6,850.3 Gm (45.791 AU) | |
Eccentricity | 0.159 |
113,183 d (309.88 a) | |
Average orbital speed | 4.419 km/s |
85.13° | |
Inclination | 28.96 ° |
79.382° | |
298.41° | |
Physical characteristics | |
Dimensions | 1,300–1,900 km |
750+200 −100 km[3] | |
~7,000,000 km²[e] | |
Volume | ~1.8 km³[D] |
Mass | ~4 kg |
Mean density | ~2 g/cm³ (assumed) |
~0.47 m/s²[g] | |
~0.84 km/s[h] | |
? | |
pole-on ? | |
Albedo | 78.2+10.3 −8.6 (geometric)[3] |
Temperature | 30–35 K [c](assuming the same albedo) |
16.7 (opposition)[4] | |
−0.48[2] | |
Makemake (Template:Pron-en, or as Rapanui [5]), formally designated (136472) Makemake, is the third-largest known dwarf planet in the Solar System and one of the two largest Kuiper belt objects (KBO) in the classical KBO population.[a] Its diameter is roughly three-quarters that of Pluto.[6] Makemake has no known satellites, which makes it unique among the largest KBOs. Its extremely low average temperature (about 30 K) means its surface is covered with methane, ethane and possibly nitrogen ices.[7]
Initially known as 2005 FY9 (and later given the minor planet number 136472), it was discovered on March 31, 2005 by a team led by Michael Brown, and announced on July 29, 2005. On June 11, 2008, the IAU included Makemake in its list of potential candidates to be given "plutoid" status, a term for dwarf planets beyond the orbit of Neptune that would place the object alongside Pluto and Eris. Makemake was formally classified as a plutoid in July 2008.[8][9][10][11]
Discovery
Makemake was discovered on March 31, 2005 by a team led by Michael Brown.[2] Its discovery was announced on July 29, 2005, which was the same day as Eris and two days after 2003 EL61.[12]
Despite its relative brightness (it is about a fifth as bright as Pluto),[b] Makemake was not discovered until well after many much fainter Kuiper belt objects. Most searches for minor planets are conducted relatively close to the ecliptic, due to the greater probability of finding objects there. Due to its relatively high orbital inclination, and the fact that it was at its farthest distance from the ecliptic (the region of the sky that the Sun, Moon and planets appear to lie in, as seen from Earth) at the time of its discovery (in the northern constellation of Coma Berenices),[4] it probably escaped detection from the earlier surveys.
Makemake is the only other dwarf planet that was bright enough for Clyde Tombaugh to have possibly detected during his search for Pluto.[13] At the time of Tombaugh's survey, Makemake was only a few degrees from the ecliptic, near the border of Taurus and Auriga,[d] at an apparent magnitude of 16.0.[4] This position, however, was also very near the Milky Way, and Makemake was almost impossible to find against the dense background of stars. Tombaugh continued searching for some years after the discovery of Pluto,[14] but he failed to find Makemake or any other trans-Neptunian objects.
Name
The provisional designation 2005 FY9 was given to Makemake when the discovery was made public. Before that, the discovery team used the codename "Easterbunny" for the object, because of its discovery shortly after Easter.[15]
In July 2008, in accordance with IAU rules for classical Kuiper belt objects, 2005 FY9 was given the name of a creator deity. The name of Makemake, the creator of humanity in the mythos of the Rapanui, the native people of Easter Island,[8] was chosen in part to preserve the object's connection with Easter.[15]
Orbit and classification
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/fe/TheKuiperBelt_Orbits_2003EL61_2005FY9.svg/250px-TheKuiperBelt_Orbits_2003EL61_2005FY9.svg.png)
As of 2008, Makemake is at a distance of 52 AU from the Sun;[4] almost as far from the Sun as it ever reaches on its orbit.[7] Makemake follows an orbit very similar to that of 2003 EL61: highly inclined (29°) and moderately eccentric (e~0.15).[16] Nevertheless, Makemake's orbit is slightly farther from the Sun (in terms of both the semi-major axis and perihelion). Its orbital period is nearly 310 years,[1] more than Pluto's 248 years and EL61's 285 years.
Both Makemake and EL61 are currently far above the ecliptic. Makemake is approaching its 2033 aphelion,[4] while EL61 passed its aphelion in late 1991.[17]
Makemake is classified a classical Kuiper belt object,[18] which means it lies in the region of the belt gravitationally unaffected by the orbit of Neptune (between 42 and 48 AU).[19][20][a] Unlike plutinos, which can cross Neptune's orbit due to their 2:3 resonance with the planet, the classical objects have perihelia further from the Sun, free from Neptune’s perturbation.[19] Such objects have relatively low eccentricities and orbit the Sun in much the same way the planets do. Makemake, however, is a member of the "dynamically hot" class of classical KBOs, meaning that it has a high inclination compared to others in its population.[21]
On August 24, 2006, the International Astronomical Union (IAU) announced a formal definition of planet that established a tripartite classification for objects in orbit around the Sun: "small Solar System bodies" were those objects too small for their gravity to have collapsed their surfaces into a rounded shape; "dwarf planets" were those objects large enough to be rounded, but who had yet to clear their orbits of similar-sized objects; "planets" were those objects that were both large enough to be rounded by self-gravity and which had cleared their orbits of similar-sized objects.[22] Under this classification, Pluto, Eris and Ceres were reclassified as dwarf planets.[22]
On June 11, 2008, the IAU further elaborated on this classification scheme by creating a subclass of dwarf planet, plutoid, specifically for those dwarf planets found beyond the orbit of Neptune. Eris and Pluto are thus plutoids, while Ceres is not. To be considered a plutoid, an object must be exceptionally bright with an absolute magnitude of H= +1,[23] which meant that only Makemake and 2003 EL61 were likely to be included.[24] On July 11, 2008, the IAU/USGS Working Group on Planetary Nomenclature included Makemake in the plutoid class, making it officially both a dwarf planet and a plutoid, alongside Pluto and Eris.[8][11]
Physical characteristics
Brightness, size, and rotation
Makemake is currently visually the second brightest Kuiper belt object after Pluto,[13] having a March opposition apparent magnitude of about 16.7 in the constellation Coma Berenices.[4] This is bright enough to be visible using a high-end amateur telescope. Makemake's high albedo of roughly 80 percent suggests an average surface temperature of about 30 K.[c][3] The size of Makemake is not precisely known, but the detection in infrared by the Spitzer space telescope, combined with the similarities of spectrum with Pluto yielded an estimate of a 1,500+400
−200 km diameter.[3] This is slightly larger than the size of 2003 EL61 making Makemake the third largest known Trans-Neptunian object after Eris and Pluto.[16] Makemake is now designated the fourth dwarf planet in the Solar System because it has a bright V-band absolute magnitude of −0.48.[2] This practically guarantees that it is large enough to achieve hydrostatic equilibrium.[8]
Error: Image is invalid or non-existent.
As of July 2008 the rotation period of Makemake was not known, because it exhibits no discernible photometric variations.[25] There two possible reasons for this: Makemake's atmosphere could be frozen to its surface, rendering it fairly homogeneous, or it may be facing Earth pole-on. In the latter case a strong asymmetry is expected in the surface composition: the currently invisible summer hemisphere would have far fewer volatiles on it than the winter hemisphere.[26]
Spectra
In a letter written to the journal Astronomy and Astrophysics in 2006, Licandro et al. reported the measurements of the visible and near infrared spectrum of Makemake. They used the William Herschel Telescope and Telescopio Nazionale Galileo and showed that the surface of Makemake resembles that of Pluto.[27] It like Pluto appears red in the visible spectrum, but significantly less red than the surface Eris (see colour comparison of TNOs).[27] The near-infrared spectrum is marked by the presence of the broad methane (CH4) absorption bands. The methane is observed also on Pluto and Eris, but its spectral signature is much weaker.[27]
Spectral analysis of Makemake's surface revealed that methane must be present in the form of large grains at least one centimetre in size.[7] In addition large amounts of ethane and tholins may be present as well, most likely created by photolysis of methane by solar radiation.[7] The tholins are probably responsible for the red color in visible. Although evidence exists for the presence of nitrogen ice on its surface, at least mixed with other ices, there is nowhere near the same level of nitrogen as on Pluto and Triton, where it composes more than 98 percent of the crust. The relative lack of nitrogen ice suggests that its supply of nitrogen has somehow been depleted over the age of the Solar System.[7][26][28]
Atmosphere
The presence of methane and possibly nitrogen suggests that Makemake could have a transient atmosphere similar to that of Pluto near its perihelion.[27] If nitrogen is present, it will be the dominant component of it.[7] The existence of atmosphere also provides a natural explanation for the nitrogen depletion: since the gravity of Makemake is weaker than that of Pluto, Eris and Triton, the large amounts of nitrogen has probably been lost via atmospheric escape; methane is lighter than nitrogen, but has significantly lower vapor pressure at temperatures prevalent at the surface of Makemake (30–35 K),[c] which hinders its escape; the result of this process is a higher relative abudance of methane.[29]
Satellites
No satellites have been detected around Makemake to a radius of 0.4 arcseconds with a brightness more than one percent of the primary.[13] This contrasts with the other largest trans-Neptunian objects, which all possess at least one satellite: Eris has one, 2003 EL61 has two and Pluto has three. From 10% to 20% of all trans-Neptunian objects are expected to have one or more satellites.[13] Since satellites offer a simple method to measure an object's mass, lack of a satellite makes obtaining an accurate figure for Makemake's mass more difficult.[13]
Notes
- ^ Astronomers Mike Brown, David Jewitt and Marc Buie classify Makemake as a near scattered object but the Minor Planet Center, from which Wikipedia draws most of its definitions for the trans-Neptunian population, places it among the main Kuiper belt population.[7][30][1][31].
- ^ It has an apparent magnitude in opposition of 16.7 vs. 15 for Pluto.[25]
- ^ Calculated using the formula
where Teff =54.8 K at 52 AU, =0.78 is the geometrical albedo, q=0.8 is the phase integral. Teff scales as , where is the distance from the Sun. All parameters are taken from Stansberry, et al., 2007.[3] - ^ Based on Minor Planet Center online Minor Planet Ephemeris Service: March 1 1930: RA: 05h51m, Dec: +29.0.
- ^ Surface area derived from the radius r: .
- ^ Volume v derived from the radius r: .
- ^ Surface gravity derived from the mass m, the gravitational constant G and the radius r: .
- ^ Escape velocity derived from the mass m, the gravitational constant G and the radius r: .
References
- ^ a b c Marc W. Buie (2008-04-05). "Orbit Fit and Astrometric record for 136472". SwRI (Space Science Department). Retrieved 2008-07-13.
- ^ a b c d e "JPL Small-Body Database Browser: 136472 (2005 FY9)". NASA Jet Propulsion Laboratory. 2008-04-05 last obs. Retrieved 2008-06-11.
{{cite web}}
: Check date values in:|date=
(help) - ^ a b c d e J. Stansberry, W. Grundy, M. Brown; et al. (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope" (abstract). The Solar System beyond Neptune. Univeristy of Arizona Press. Retrieved 2008-08-04.
{{cite journal}}
: Explicit use of et al. in:|author=
(help); Unknown parameter|month=
ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b c d e f "Asteroid 136472 Makemake (2005 FY9)". HORIZONS Web-Interface. JPL Solar System Dynamics. Retrieved 2008-07-01.
- ^ Robert D. Craig (2004). Handbook of Polynesian Mythology. ABC-CLIO. p. 63. ISBN 1576078949. Retrieved 2008-07-14.
- ^ Michael E. Brown (2006). "The discovery of 2003 UB313 Eris, the 10th planet largest known dwarf planet". California Institute of Technology. Retrieved 2008-07-14.
- ^ a b c d e f g Mike Brown, K. M. Barksume, G. L. Blake, E. L. Schaller, D. L. Rabinowitz, H. G. Roe and C. A. Trujillo (2007). "Methane and Ethane on the Bright Kuiper Belt Object 2005 FY9". The Astronomical Journal. 133: 284–289. doi:10.1086/509734.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ a b c d "Dwarf Planets and their Systems". Working Group for Planetary System Nomenclature (WGPSN). U.S. Geological Survey. 2008-11-07 11:42:58. Retrieved 2008-07-13.
{{cite web}}
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(help) - ^ Gonzalo Tancredi, Sofia Favre (2008). "Which are the dwarfs in the Solar System?" (PDF). Icarus. 195 (2): 851–862. doi:10.1016/j.icarus.2007.12.020. Retrieved 2008-08-03.
{{cite journal}}
: Unknown parameter|month=
ignored (help) - ^ Michael E. Brown. "The Dwarf Planets". California Institute of Technology, Department of Geological Sciences. Retrieved 2008-01-26.
- ^ a b International Astronomical Union (2008-07-19). "Fourth dwarf planet named Makemake" (Press release). International Astronomical Union (News Release - IAU0806). Retrieved 2008-07-20.
- ^ Thomas H. Maugh II and John Johnson Jr. (2005). "His Stellar Discovery Is Eclipsed". Los Angeles Times. Retrieved 2008-07-14.
- ^ a b c d e M. E. Brown, M. A. van Dam, A. H. Bouchez; et al. (2006-03-01). "Satellites of the Largest Kuiper Belt Objects". The Astrophysical Journal. 639: L43–L46. doi:10.1086/501524.
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(help)CS1 maint: multiple names: authors list (link) - ^ "Clyde W. Tombaugh". New Mexico Museum of Space History. Retrieved 2008-06-29.
- ^ a b Mike Brown (2008). "Mike Brown's Planets: What's in a name? (part 2)". California Institute of Technology. Retrieved 2008-07-14.
- ^ a b S. C. Tegler, W. M. Grundy, W. Romanishin, G. J. Consolmagno, K. Mogren, F. Vilas (2007-01-08). "Optical Spectroscopy of the Large Kuiper Belt Objects 136472 (2005 FY9) and 136108 (2003 EL61)". The Astronomical Journal. 133: 526–530. doi:10.1086/510134.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ "Asteroid 136108 (2003 EL61)". HORIZONS Web-Interface. JPL Solar System Dynamics. Retrieved 2008-08-04.
- ^ Brian G. Marsden (2006-12-12). "Minor Planet Electronic Circular 2006-X45: Distant Minor Planets". IAU Minor Planet Center. Harvard-Smithsonian Center for Astrophysics. Retrieved 2008-08-04.
- ^ a b David Jewitt (2000). "Classical Kuiper Belt Objects (CKBOs)". University of Hawaii. Retrieved 2008-08-04.
{{cite web}}
: Unknown parameter|month=
ignored (help) - ^ Jane X. Luu and David C. Jewitt (2002). "Kuiper Belt Objects: Relics from the Accretion Disk of the Sun" (pdf). Ann. Rev. Astron. Astrophys. 40: 63–101. doi:10.1146/annurev.astro.40.060401.093818. Retrieved 2008-08-04.
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at position 13 (help) - ^ Harold F. Levison, Alessandro Morbidelli (2003). "The formation of the Kuiper belt by the outward transport of bodies during Neptune's migration" (pdf). Nature. 426: 419–421. doi:10.1038/nature02120. Retrieved 2007-06-25.
- ^ a b "IAU 2006 General Assembly: Result of the IAU Resolution votes" (Press release). International Astronomical Union (News Release - IAU0603). 2006-08-24. Retrieved 2007-12-31. (orig link)
- ^ "Plutoid chosen as name for Solar System objects like Pluto" (Press release). Paris: International Astronomical Union (News Release - IAU0804). 2008-06-11. Retrieved 2008-06-11.
- ^ Michael Brown (2008). "Mike Brown's Planets:Plutoid fever" (blog). Retrieved 2008-07-14.
- ^ a b David L. Rabinowitz, Bradley E. Schaefer, Suzanne W. Tourtellotte (2007). "The Diverse Solar Phase Curves of Distant Icy Bodies. I. Photometric Observations of 18 Trans-Neptunian Objects, 7 Centaurs, and Nereid". The Astronomical Journal. 133: 26–43. doi:10.1086/508931. Retrieved 2008-08-03.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ a b S.C. Tegler, W.M. Grundy, F. Vilas, W. Romanishin, D.M. Cornelison and G.J. Consolmagno (2008). "Evidence of N2-ice on the surface of the icy dwarf Planet 136472 (2005 FY9)". Icarus. 195 (2): 844–850. doi:10.1016/j.icarus.2007.12.015.
{{cite journal}}
: Unknown parameter|month=
ignored (help)CS1 maint: multiple names: authors list (link) - ^ a b c d J. Licandro, N. Pinilla-Alonso, M. Pedani, E. Oliva, G. P. Tozzi, W. M. Grundy (2006). "The methane ice rich surface of large TNO 2005 FY9: a Pluto-twin in the trans-neptunian belt?". Astronomy and Astrophysics. 445 (3): L35–L38. doi:10.1051/0004-6361:200500219.
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - ^ Tobias C. Owen, Ted L. Roush; et al. (1993-08-06). "Surface Ices and the Atmospheric Composition of Pluto". Science. 261 (5122): 745–748. doi:10.1126/science.261.5122.745. PMID 17757212. Retrieved 2008-08-03.
{{cite journal}}
: Explicit use of et al. in:|author=
(help) - ^ E.L. Schaller, M.E. Brown (2007-04-10). "Volatile Loss and Retention on Kuiper Belt Objects". The Astrophysical Journal. 659: L61–L64. doi:10.1086/516709.
- ^ Audrey Delsanti, David Jewitt. "The Solar System Beyond The Planets" (PDF). University of Hawaii. Retrieved 2008-08-03.
- ^ "List Of Transneptunian Objects". Minor Planet Center. Harvard-Smithsonian Chenter for Astrophysics. Retrieved 2008-08-03.
External links
- MPEC listing for Makemake
- AstDys orbital elements
- Orbital simulation from JPL (Java) / Ephemeris
- Press release from WHT and TNG on Makemake's similarity to Pluto.
- Makemake chart and Orbit Viewer
- Precovery image with the 1.06 m Kleť Observatory telescope on 2003 April 20
- Makemake of the Outer Solar System APOD July 15, 2008