(136472) 2005 FY₉

Artist's conception of 2005 FY9
Discovery
Discovered by:	Michael E. Brown, Chad Trujillo, David Rabinowitz
Discovery date:	March 31, 2005
Orbital characteristics
Epoch January 28, 1955 (JD 2435135.5)
Aphelion	7939.7 Gm (53.0736 AU)
Perihelion:	5760.7 Gm (38.508 AU)
Semi-major axis:	6850.2 Gm (45.791 AU)
Eccentricity:	0.159
Orbital period:	113179 d (309.868 a)
Avg. orbital speed:	4.419 km/s
Mean anomaly:	85.14653°
Inclination:	28.963°
Longitude of ascending node:	79.3816°
Argument of perihelion:	298.407°
Physical characteristics
Dimensions:	1300 – 1900 km
Mean radius:	1500+400-200 km[1]
Surface area:	~ 7000000 km²
Volume:	~ 1.8×109 km³
Mass:	~ 4×1021 kg
Mean density:	~2 g/cm³
Equatorial surface gravity:	~ 0.5 m/s²
Escape velocity:	~ 0.8 km/s
Albedo:	0.8 ± 0.2
Temperature:	~30 K
Absolute magnitude:	-0.4

(136472) 2005 FY₉ (also written (136472) 2005 FY9) is a very large Kuiper belt object, and one of the two largest among the population in the classical KBO orbits. It was discovered on March 31, 2005 by the team led by Michael Brown. Prior to making it public, the discovery team referred to it by the codename "Easterbunny". The designation 2005 FY₉ is only provisional, and it will eventually receive a permanent name after a creation deity from the International Astronomical Union. Image File history File links No higher resolution available. ... Michael (Mike) E. Brown (born c. ... Chadwick A. Chad Trujillo (born November 22, 1973), is the co-discoverer of Eris, which he claims to be the Tenth Planet. ... David L. Rabinowitz (born 1960) is a professor at Yale University researching the Kuiper belt and the outer solar system. ... is the 90th day of the year (91st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... is the 28th day of the year in the Gregorian calendar. ... Year 1955 (MCMLV) was a common year starting on Saturday (link displays the 1955 Gregorian calendar). ... “JDN” redirects here. ... A diagram of Keplerian orbital elements. ... A diagram of Keplerian orbital elements. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... Look up giga- in Wiktionary, the free dictionary. ... This article is about the unit of length. ... The astronomical unit (AU or au or a. ... (This page refers to eccitricity in astrodynamics. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Look up day in Wiktionary, the free dictionary. ... In astronomy, a Julian year is a unit of time defined as exactly 365. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... This article is about the unit of time. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... For the science fiction novella by William Shunn, see Inclination (novella). ... This article describes the unit of angle. ... The Longitude of the ascending node (☊, also noted Ω) is one of the orbital elements used to specify the orbit of an object in space. ... The argument of periapsis (ω) is the orbital element describing the angle between an orbiting bodys ascending node (the point where the body crosses the plane of reference from South to North) and its periapsis (the point of closest approach to the central body), measured in the orbital plane and... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ... For other uses, see Volume (disambiguation). ... For other uses, see Mass (disambiguation). ... Kg redirects here. ... For other uses, see Density (disambiguation). ... A cubic centimetre (cm3) is an SI derived unit of volume, equal to the volume of a cube with side length of 1 centi metre. ... The surface gravity of a Killing horizon is the acceleration, as exerted at infinity, needed to keep an object at the horizon. ... Space Shuttle Atlantis launches on mission STS-71. ... For other uses, see Albedo (disambiguation). ... For other uses, see Temperature (disambiguation). ... For other uses, see Kelvin (disambiguation). ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... The Kuiper belt (KYE per) is an area of the solar system extending from within the orbit of Neptune (at 30 AU) to 50 AU from the sun, at inclinations consistent with the ecliptic. ... A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... is the 90th day of the year (91st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Michael (Mike) E. Brown (born c. ... THIS IS A FACT Creation is a doctrinal position in many religions and philosophical belief systems which maintains that a single God, or a group of or deities is responsible for creating the universe. ... Look up deity in Wiktionary, the free dictionary. ... IAU redirects here. ...

Physical characteristics

(136472) 2005 FY₉ compared to Eris, Pluto, (136108) 2003 EL₆₁, Sedna, Orcus, Quaoar, Varuna, and Earth.

Image File history File links Download high-resolution version (2750x1995, 1859 KB) Summary Comparison of the eight largest TNOs, based on the public domain NASA image: Image:2006-16-d-print. ...

Size and brightness

(136472) 2005 FY₉ is currently visually the second brightest Kuiper belt object after Pluto having the apparent magnitude of nearly 17, bright enough to be visible using a high-end amateur telescope. The size of 2005 FY₉ is not currently known, but the detection in infrared by the Spitzer space telescope, combined with the similarities of spectrum with Pluto yielded an estimate of a 1500⁺⁴⁰⁰_-200 km diameter ^[1]. This is slightly larger than the size of 2003 EL₆₁ making 2005 FY₉ the third largest known Trans-Neptunian object after Eris and Pluto. Currently 2005 FY₉ is the best candidate to be designated the fourth dwarf planet in the Solar System.^{[2] [3]} The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... Amateur astronomy, often called back yard astronomy, is a hobby whose participants enjoy observing celestial objects. ... This article does not cite any references or sources. ... The Spitzer Space Telescope (formerly the Space Infrared Telescope Facility [SIRTF]) is an infrared space observatory, the fourth and final of NASAs Great Observatories. ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... For other uses, see Pluto (disambiguation). ... Artists impression of Pluto (background) and Charon (foreground). ... This article is about the Solar System. ...

Spectra

In a recent paper, Licandro et al. showed that the surface of 2005 FY₉ resembles that of Pluto by measuring its visible and near infrared spectrum using the William Herschel Telescope and Telescopio Nazionale Galileo. It appears red in the visible spectrum, as opposed to e.g. Eris which has a neutral spectrum (see colour comparison for TNOs). The infrared spectrum is marked by the presence of methane (CH₄), as also observed on Pluto and Eris. Its presence, more prominent even than on Pluto, suggests that 2005 FY₉ could have a transient atmosphere similar to Pluto's near perihelion. Legend: γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves: EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultrahigh frequency VHF = Very high frequency HF = High frequency... This article is about the telescope on the Canary Islands. ... The Telescopio Nazionale Galileo, or TNG is a 3. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... Methane is a chemical compound with the molecular formula . ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... A diagram of Keplerian orbital elements. ...

Satellites

No satellites have been detected, a situation different from the other largest known trans-Neptunian objects: Eris (1 satellite), 2003 EL61 (2 satellites) and Pluto (3 satellites). From 10% to 20% of all trans-Neptunian objects are expected to have one or more satellites. Eris typically refers to: Eris (dwarf planet), 136199 Eris , the largest known dwarf planet in the Solar System (provisional designation ) Eris (mythology), in Greek mythology the goddess of discord, and the Goddess of Discordianism It may also refer to: Eris (Billy and Mandy), a humorous representation of the Greek goddess... 2003 EL61 (also written 2003 EL61), nicknamed Santa (non-official designation), is a large and very unusual Kuiper belt object discovered by Mike Brown at Caltech in the United States. ... For other uses, see Pluto (disambiguation). ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ...

Discovery circumstances

2005 FY₉ was discovered on March 31, 2005 by the team led by Michael Brown. Its discovery was announced on July 29, 2005 on the same day as two other very large trans-Neptunian objects, 2003 EL₆₁ and Eris. The designation 2005 FY₉ was given to the object when the discovery was made public. Before that, the discovery team used the codename "Easterbunny" for the object because of the discovery time shortly after Easter. The designation is only provisional; according to the current naming rules of the International Astronomical Union, it will receive a permanent name after a creation deity. is the 90th day of the year (91st in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Michael (Mike) E. Brown (born c. ... is the 210th day of the year (211th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... 2003 EL61 (also written 2003 EL61), nicknamed Santa (non-official designation), is a large and very unusual Kuiper belt object discovered by Mike Brown at Caltech in the United States. ... Absolute magnitude: −1. ... The provisional designation of comets and asteroids are similar to each other: they both follow a pattern set in 1925 by the Minor Planet Center of the IAU. Historical designations At first, astronomers strove to assign symbols to the minor planets: 1 Ceres a stylized sickle 2 Pallas a lozenge... This article is about the Christian festival. ... IAU redirects here. ... THIS IS A FACT Creation is a doctrinal position in many religions and philosophical belief systems which maintains that a single God, or a group of or deities is responsible for creating the universe. ... Look up deity in Wiktionary, the free dictionary. ...

Despite its relative brightness, 2005 FY₉ was not discovered until fairly recently, well after many much fainter Kuiper belt objects. This is probably due to its relatively high orbital inclination, and the fact that its angular distance from the ecliptic was near maximum at the time of its discovery (in the northern constellation of Coma Berenices). Most searches for minor planets are conducted relatively close to the ecliptic, due to the greater probability of finding objects there. For the science fiction novella by William Shunn, see Inclination (novella). ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... Coma Berenices (IPA: , Latin: ) is a traditional asterism that has since become a constellation. ...

However, at the time of Clyde Tombaugh's discovery of Pluto, 2005 FY₉ was only a few degrees from the ecliptic, near the border of Taurus and Auriga. Unfortunately, this position was also very near the galactic equator, making it almost impossible to find such an object within the dense concentration of background stars of the Milky Way. Tombaugh continued searching for some years after the discovery of Pluto, but he failed to find 2005 FY₉ or any other trans-Neptunian objects. An image of Clyde Tombaugh Clyde William Tombaugh (February 4, 1906 – January 17, 1997) was an American astronomer who discovered the dwarf planet Pluto in 1930. ... For other uses, see Pluto (disambiguation). ... Taurus (IPA: , Latin: , symbol , ) is one of the constellations of the zodiac. ... Auriga (IPA: , Latin: ) is a northern constellation. ... Many galaxies, including the Milky Way in which our Sun and Earth are located, are disk-shaped: the majority of their visible mass (excluding possible dark matter) lies very close to a plane. ...

Orbit

Orbits of 2005 FY₉ (blue), 2003 EL₆₁ (green) and Pluto (red).

2005 FY₉ is classified a classical Kuiper belt object and follows an orbit very similar to that of 2003 EL₆₁: highly inclined (29°) and moderately eccentric (e~0.16). 2005 FY₉ is slightly farther from the Sun (in terms of both the semi major axis and perihelion). Unlike Pluto and the other plutinos, which can cross Neptune's orbit due to their resonance, the classical objects have perihelia further from the Sun, free from Neptune’s perturbation. Its orbital period is nearly 310 Earth years, more than Pluto. Image File history File links TheKuiperBelt_Orbits_2003EL61_2005FY9. ... Image File history File links TheKuiperBelt_Orbits_2003EL61_2005FY9. ... 2003 EL61 (also written 2003 EL61), nicknamed Santa (non-official designation), is a large and very unusual Kuiper belt object discovered by Mike Brown at Caltech in the United States. ... For other uses, see Pluto (disambiguation). ... A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... The Kuiper belt, derived from data from the Minor Planet Center. ... 2003 EL61 (also written 2003 EL61), nicknamed Santa (non-official designation), is a large and very unusual Kuiper belt object discovered by Mike Brown at Caltech in the United States. ... Inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit and is the angular distance of the orbital plane from the plane of the reference (usually planets equator or the ecliptic), stated in degrees. ... (This page refers to eccitricity in astrodynamics. ... In astronomy, a plutino is a trans-Neptunian object that has a 3:2 orbital resonance with Neptune. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... In astrodynamics orbital perturbation is an effect on an objects orbit due to the range of external influences. ...

The diagram shows the similar orbits of the two cubewanos contrasted with the orbit of Pluto. The perihelia (q) and the aphelia (Q) are marked with the dates of passage. The present positions (as of April 2006) are marked with the spheres illustrating relative sizes and differences in albedo and colour. Both cubewanos are currently far above the ecliptic (illustrated as Neptune's orbit in grey). 2005 FY₉ is approaching its aphelion while 2003 EL₆₁ passed its own in 1991. A cubewano is any substantial Kuiper belt object, orbiting beyond about 41 AU and not controlled by resonances with the outer planets. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ...

External links

• MPEC listing for 2005 FY₉
• AstDys orbital elements
• Orbital simulation from JPL (Java)
• Press release from WHT and TNG on 2005 FY₉ 's similarity to Pluto.
• 2005 FY9 chart and Orbit Viewer

Moonrise over the WHT dome The William Herschel Telescope or WHT is a 4. ... The Telescopio Nazionale Galileo, or TNG is a 3. ...

References

• Licandro, J.; Pinilla-Alonso, N.; Pedani, M.; Oliva, E.; Tozzi, G. P.; Grundy, W. M. The methane ice rich surface of large TNO 2005 FY_9: a Pluto-twin in the trans-neptunian belt? , Astronomy and Astrophysics, 445 (2006), pp. L35-L38 Abstract.