 Stacked
Hubble Space Telescope images of ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu | |
| Discovery [1] | |
|---|---|
| Discovered by | Marc Buie |
| Discovery site | Kitt Peak Observatory |
| Discovery date | 11 March 2005 |
| Designations | |
| (469705) ﾇKﾃ｡ﾌｦgﾃ｡ra | |
| Pronunciation |
|
Named after | ﾇKﾃ｡ﾌｦgﾃ｡ra ( San mythology) [2] |
| 2005 EF298 | |
| Cold classical KBO [2] | |
| Orbital characteristics [3] [1] | |
| Epoch ( JD 2458600.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 10.10 yr (3688 d) |
| Aphelion | 44.058 AU |
| Perihelion | 40.013 AU |
| 44.081 AU | |
| Eccentricity | 0.085 |
| 292.45 yr (106744.25 d) | |
| 118.059 ﾂｰ | |
| 0.00337 0ﾂｰ 0m 0s / day | |
| Inclination | 1.60ﾂｰ |
| 118.059ﾂｰ | |
| 77.966ﾂｰ | |
| Known satellites | 1 [4] |
| Physical characteristics | |
| 138+21 竏25 km, assuming same albedo as ﾇォﾃ｣unu | |
| Mass | (1.29ﾂｱ0.07)ﾃ1018 kg, assuming same density and albedo as ﾇォﾃ｣unu |
Mean
density | 1.1+0.9 竏0.4 g/cm3, assuming equal compositions of the bodies |
| HV = 6.2ﾂｱ0.5 | |
469705 ﾇKﾃ｡ﾌｦgﾃ｡ra (provisional designation 2005 EF298) is a trans-Neptunian object and binary system of the core Kuiper belt, located in the outermost region of the Solar System. It was discovered on 11 March 2005 by American astronomer Marc Buie at the Kitt Peak Observatory in Arizona. [1] The primary body measures around 140 kilometers (90 miles) in diameter. Its 120-kilometer (75-mile) companion ﾇォﾃ｣unu was discovered with the Hubble Space Telescope in 2009. The ﾇKﾃ｡ﾌｦgﾃ｡ra窶読ォﾃ｣unu system is currently undergoing mutual occultation and eclipsing events in which one body casts a shadow on or obstructs the view of the other as seen from Earth.
The names ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu are from the mythology of the ﾇXam people of South Africa. ﾇKﾃ｡ﾌｦgﾃ｡ra (also rendered ﾇKaﾊｻgara) and his brother-in-law ﾇォﾃ｣unu fought an epic battle in the east using thunder and lightning, producing mountainous clouds and rain. The conflict was fought over ﾇKﾃ｡ﾌｦgﾃ｡ra's returning his younger sister, ﾇォﾃ｣unu's wife, to their parents. [2] [5] The names were approved and an official naming citation was published on 16 June 2021 by the International Astronomical Union's Working Group on Small Body Nomenclature. [6]
In the ﾇXam language, ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu are thought to have been pronounced [ﾇは｡kﾃ｡ﾋ､ﾉ｡ﾃ｡ﾉｾa] [Note 1] and [盞体管μｰﾉ冰nu] , [Note 2] respectively. [7] The initial letters ﾇK and !H (and indeed the letter ﾇX in 'ﾇXam') represent some of the many click consonants that characterize ﾇXam and other San languages. The diacritic under the first vowel in ﾇKﾃ｡ﾌｦgﾃ｡ra indicates that it is a pharyngealized vowel, another characteristic of San languages. When pronounced in English, the click consonants in words from ﾇXam and other San languages are usually ignored (much as Xhosa is pronounced /ﾋkoﾊzﾉ/ ( KOH-zﾉ) rather than [ﾇ¬ｰosa]), resulting in /ﾋkﾉ騨ﾊﾉ｡ﾉ騨rﾉ/ ( KAHﾊｼ-gar-ﾉ) and /ﾋhaﾊnuﾋ/ ( HOW-noo).[ citation needed] ASCII approximations of the names are =Ka'gara and !Haunu.
ﾇKﾃ｡ﾌｦgﾃ｡ra is a cold classical Kuiper belt object. It orbits the Sun at a distance of 44 AU once every 290 years. Its orbit has an eccentricity of 0.09 and an inclination of 3 degrees with respect to the ecliptic. [3]
If the two bodies are spheres with equal density, then mutual occultation events between ﾇKﾃ｡ﾌｦgﾃ｡ra and its satellite ﾇォﾃ｣unu should have begun in 2015 and should continue until 2035. When ﾇKﾃ｡ﾌｦgﾃ｡ra passes in front of ﾇォﾃ｣unu, events may last as long as 8 hours, but when ﾇォﾃ｣unu passes in front of ﾇKﾃ｡ﾌｦgﾃ｡ra they are expected to last as long as 2 days. These latter events are only expected to occur from 2022 to 2027. [2]
Prograde orbits dominate tight binary systems such as 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra, those with satellite semimajor axes less than about 5% of their Hill radii. Grundy et al. suggest that this could be "the signature of planetesimal formation through gravitational collapse of local density enhancements such as caused by the streaming instability", [2] which has been suggested as the formative mechanism of the only visited planetesimal, 486958 Arrokoth.
| Discovery | |
|---|---|
| Discovery date | 2009 |
| Designations | |
| Pronunciation |
|
Named after | ﾇォﾃ｣unu ( San mythology) [2] |
| |
| Orbital characteristics [2] [8] [4] | |
| 7670ﾂｱ140 km | |
| Eccentricity | 0.694ﾂｱ0.013 |
| 128.107ﾂｱ0.027 d (prograde) | |
| Inclination |
|
| Physical characteristics | |
| 122+16 竏19 km, assuming same albedo as ﾇKﾃ｡ﾌｦgﾃ｡ra | |
| Mass | (0.89ﾂｱ0.05)ﾃ1018 kg, assuming same density and albedo as ﾇKﾃ｡ﾌｦgﾃ｡ra |
| ﾎ禰 = 0.59 | |
469705 ﾇKﾃ｡ﾌｦgﾃ｡ra has one known satellite, ﾇォﾃ｣unu. The magnitude difference between ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu is 0.59 mag. This corresponds to a difference in diameter of 13%, if the two bodies have the same albedo. [2]
The system mass is (2.18ﾂｱ0.12)ﾃ1018 kg, and, given the albedo, the bodies are equivalent to a single sphere of diameter 174+27
竏32 km. This corresponds to a density of 1.1+0.9
竏0.4 g/cm3. This does not particularly constrain the composition of the bodies, as the error bars cover the densities of both small, porous bodies and larger, collapsed bodies. Assuming the two bodies have the same albedo and density, their masses are (1.29ﾂｱ0.07)ﾃ1018 kg and (0.89ﾂｱ0.05)ﾃ1018 kg, and their diameters are 138+21
竏25 km and 122+16
竏19 km.
[2]
- ^ Bleek & Lloyd wrote ⟨ﾇＬ⟩ when the posterior release of the click was audible. Based on the sounds attested in the closely related language Nﾇ］g, this [ﾇは｡k] may therefore represent a palatal pulmonic-contour click, though this is not certain.
- ^ Based on the co-occurrence of the letter ⟨H⟩ for aspiration of the click and the tilde for nasalization on the following vowel, together with the patterns of sounds in Nﾇ］g, it is suspected that the click in ﾇォﾃ｣unu has delayed aspiration (i.e., is a long, aspirated, nasalized click), rather than a simple IPA: [ﾇμｰﾉ厠ブnu], though again this is not certain.
- ^ a b c "469705 (2005 EF298)". Minor Planet Center. Retrieved 7 April 2019.
- ^ a b c d e f g h i Grundy, W.M.; Noll, K.S.; Roe, H.G.; Buie, M.W.; Porter, S.B.; Parker, A.H.; Nesvornﾃｽ, D.; Levison, H.F.; Benecchi, S.D.; Stephens, D.C.; Trujillo, C.A. (April 2019). "Mutual orbit orientations of transneptunian binaries". Icarus. 334: 62窶78. doi: 10.1016/j.icarus.2019.03.035. Retrieved 6 April 2019. (heliocentric parameters averaged over 10Myr)
- ^ a b "JPL Small-Body Database Browser: 469705 (2005 EF298)" (2015-04-06 last obs.). Jet Propulsion Laboratory. Retrieved 7 April 2019.
- ^ a b Johnston, Wm. Robert (27 May 2019). "Asteroids with Satellites Database 窶 (469705) 2005 EF298". Johnston's Archive. Retrieved 18 June 2021.
- ^ 竕kagara's fight with !haunu in the east. Lucy Lloyd |xam notebooks, vol. VIII-30, July 1879.
- ^ "WGSBN Bulletin" (PDF), Working Group Small Body Nomenclature, vol. 1, no. 3, p. 15, 16 June 2021
- ^ Will Grundy: 469705 (how to say)
- ^ "ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu (469705 2005 EF298)". Mutual Orbits of Binary Transneptunian Objects. Retrieved 7 April 2019. (heliocentric parameters averaged over 10Myr)
- Asteroids with Satellites, Johnston's Archive
- List of Known Trans-Neptunian Objects, Johnston's Archive
- List of Transneptunian Objects, Minor Planet Center
- 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra at the JPL Small-Body Database
- 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra at AstDyS-2, Asteroids窶妊ynamic Site
Natural satellites of the
Solar System | ||
|---|---|---|
|
Planetary satellites of |    | |
|
Dwarf planet satellites of | ||
|
Minor-planet moons | ||
| Ranked by size | ||
|
Stacked
Hubble Space Telescope images of ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu | |
| Discovery [1] | |
|---|---|
| Discovered by | Marc Buie |
| Discovery site | Kitt Peak Observatory |
| Discovery date | 11 March 2005 |
| Designations | |
| (469705) ﾇKﾃ｡ﾌｦgﾃ｡ra | |
| Pronunciation |
|
Named after | ﾇKﾃ｡ﾌｦgﾃ｡ra ( San mythology) [2] |
| 2005 EF298 | |
| Cold classical KBO [2] | |
| Orbital characteristics [3] [1] | |
| Epoch ( JD 2458600.5) | |
| Uncertainty parameter 3 | |
| Observation arc | 10.10 yr (3688 d) |
| Aphelion | 44.058 AU |
| Perihelion | 40.013 AU |
| 44.081 AU | |
| Eccentricity | 0.085 |
| 292.45 yr (106744.25 d) | |
| 118.059 ﾂｰ | |
| 0.00337 0ﾂｰ 0m 0s / day | |
| Inclination | 1.60ﾂｰ |
| 118.059ﾂｰ | |
| 77.966ﾂｰ | |
| Known satellites | 1 [4] |
| Physical characteristics | |
| 138+21 竏25 km, assuming same albedo as ﾇォﾃ｣unu | |
| Mass | (1.29ﾂｱ0.07)ﾃ1018 kg, assuming same density and albedo as ﾇォﾃ｣unu |
Mean
density | 1.1+0.9 竏0.4 g/cm3, assuming equal compositions of the bodies |
| HV = 6.2ﾂｱ0.5 | |
469705 ﾇKﾃ｡ﾌｦgﾃ｡ra (provisional designation 2005 EF298) is a trans-Neptunian object and binary system of the core Kuiper belt, located in the outermost region of the Solar System. It was discovered on 11 March 2005 by American astronomer Marc Buie at the Kitt Peak Observatory in Arizona. [1] The primary body measures around 140 kilometers (90 miles) in diameter. Its 120-kilometer (75-mile) companion ﾇォﾃ｣unu was discovered with the Hubble Space Telescope in 2009. The ﾇKﾃ｡ﾌｦgﾃ｡ra窶読ォﾃ｣unu system is currently undergoing mutual occultation and eclipsing events in which one body casts a shadow on or obstructs the view of the other as seen from Earth.
The names ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu are from the mythology of the ﾇXam people of South Africa. ﾇKﾃ｡ﾌｦgﾃ｡ra (also rendered ﾇKaﾊｻgara) and his brother-in-law ﾇォﾃ｣unu fought an epic battle in the east using thunder and lightning, producing mountainous clouds and rain. The conflict was fought over ﾇKﾃ｡ﾌｦgﾃ｡ra's returning his younger sister, ﾇォﾃ｣unu's wife, to their parents. [2] [5] The names were approved and an official naming citation was published on 16 June 2021 by the International Astronomical Union's Working Group on Small Body Nomenclature. [6]
In the ﾇXam language, ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu are thought to have been pronounced [ﾇは｡kﾃ｡ﾋ､ﾉ｡ﾃ｡ﾉｾa] [Note 1] and [盞体管μｰﾉ冰nu] , [Note 2] respectively. [7] The initial letters ﾇK and !H (and indeed the letter ﾇX in 'ﾇXam') represent some of the many click consonants that characterize ﾇXam and other San languages. The diacritic under the first vowel in ﾇKﾃ｡ﾌｦgﾃ｡ra indicates that it is a pharyngealized vowel, another characteristic of San languages. When pronounced in English, the click consonants in words from ﾇXam and other San languages are usually ignored (much as Xhosa is pronounced /ﾋkoﾊzﾉ/ ( KOH-zﾉ) rather than [ﾇ¬ｰosa]), resulting in /ﾋkﾉ騨ﾊﾉ｡ﾉ騨rﾉ/ ( KAHﾊｼ-gar-ﾉ) and /ﾋhaﾊnuﾋ/ ( HOW-noo).[ citation needed] ASCII approximations of the names are =Ka'gara and !Haunu.
ﾇKﾃ｡ﾌｦgﾃ｡ra is a cold classical Kuiper belt object. It orbits the Sun at a distance of 44 AU once every 290 years. Its orbit has an eccentricity of 0.09 and an inclination of 3 degrees with respect to the ecliptic. [3]
If the two bodies are spheres with equal density, then mutual occultation events between ﾇKﾃ｡ﾌｦgﾃ｡ra and its satellite ﾇォﾃ｣unu should have begun in 2015 and should continue until 2035. When ﾇKﾃ｡ﾌｦgﾃ｡ra passes in front of ﾇォﾃ｣unu, events may last as long as 8 hours, but when ﾇォﾃ｣unu passes in front of ﾇKﾃ｡ﾌｦgﾃ｡ra they are expected to last as long as 2 days. These latter events are only expected to occur from 2022 to 2027. [2]
Prograde orbits dominate tight binary systems such as 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra, those with satellite semimajor axes less than about 5% of their Hill radii. Grundy et al. suggest that this could be "the signature of planetesimal formation through gravitational collapse of local density enhancements such as caused by the streaming instability", [2] which has been suggested as the formative mechanism of the only visited planetesimal, 486958 Arrokoth.
| Discovery | |
|---|---|
| Discovery date | 2009 |
| Designations | |
| Pronunciation |
|
Named after | ﾇォﾃ｣unu ( San mythology) [2] |
| |
| Orbital characteristics [2] [8] [4] | |
| 7670ﾂｱ140 km | |
| Eccentricity | 0.694ﾂｱ0.013 |
| 128.107ﾂｱ0.027 d (prograde) | |
| Inclination |
|
| Physical characteristics | |
| 122+16 竏19 km, assuming same albedo as ﾇKﾃ｡ﾌｦgﾃ｡ra | |
| Mass | (0.89ﾂｱ0.05)ﾃ1018 kg, assuming same density and albedo as ﾇKﾃ｡ﾌｦgﾃ｡ra |
| ﾎ禰 = 0.59 | |
469705 ﾇKﾃ｡ﾌｦgﾃ｡ra has one known satellite, ﾇォﾃ｣unu. The magnitude difference between ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu is 0.59 mag. This corresponds to a difference in diameter of 13%, if the two bodies have the same albedo. [2]
The system mass is (2.18ﾂｱ0.12)ﾃ1018 kg, and, given the albedo, the bodies are equivalent to a single sphere of diameter 174+27
竏32 km. This corresponds to a density of 1.1+0.9
竏0.4 g/cm3. This does not particularly constrain the composition of the bodies, as the error bars cover the densities of both small, porous bodies and larger, collapsed bodies. Assuming the two bodies have the same albedo and density, their masses are (1.29ﾂｱ0.07)ﾃ1018 kg and (0.89ﾂｱ0.05)ﾃ1018 kg, and their diameters are 138+21
竏25 km and 122+16
竏19 km.
[2]
- ^ Bleek & Lloyd wrote ⟨ﾇＬ⟩ when the posterior release of the click was audible. Based on the sounds attested in the closely related language Nﾇ］g, this [ﾇは｡k] may therefore represent a palatal pulmonic-contour click, though this is not certain.
- ^ Based on the co-occurrence of the letter ⟨H⟩ for aspiration of the click and the tilde for nasalization on the following vowel, together with the patterns of sounds in Nﾇ］g, it is suspected that the click in ﾇォﾃ｣unu has delayed aspiration (i.e., is a long, aspirated, nasalized click), rather than a simple IPA: [ﾇμｰﾉ厠ブnu], though again this is not certain.
- ^ a b c "469705 (2005 EF298)". Minor Planet Center. Retrieved 7 April 2019.
- ^ a b c d e f g h i Grundy, W.M.; Noll, K.S.; Roe, H.G.; Buie, M.W.; Porter, S.B.; Parker, A.H.; Nesvornﾃｽ, D.; Levison, H.F.; Benecchi, S.D.; Stephens, D.C.; Trujillo, C.A. (April 2019). "Mutual orbit orientations of transneptunian binaries". Icarus. 334: 62窶78. doi: 10.1016/j.icarus.2019.03.035. Retrieved 6 April 2019. (heliocentric parameters averaged over 10Myr)
- ^ a b "JPL Small-Body Database Browser: 469705 (2005 EF298)" (2015-04-06 last obs.). Jet Propulsion Laboratory. Retrieved 7 April 2019.
- ^ a b Johnston, Wm. Robert (27 May 2019). "Asteroids with Satellites Database 窶 (469705) 2005 EF298". Johnston's Archive. Retrieved 18 June 2021.
- ^ 竕kagara's fight with !haunu in the east. Lucy Lloyd |xam notebooks, vol. VIII-30, July 1879.
- ^ "WGSBN Bulletin" (PDF), Working Group Small Body Nomenclature, vol. 1, no. 3, p. 15, 16 June 2021
- ^ Will Grundy: 469705 (how to say)
- ^ "ﾇKﾃ｡ﾌｦgﾃ｡ra and ﾇォﾃ｣unu (469705 2005 EF298)". Mutual Orbits of Binary Transneptunian Objects. Retrieved 7 April 2019. (heliocentric parameters averaged over 10Myr)
- Asteroids with Satellites, Johnston's Archive
- List of Known Trans-Neptunian Objects, Johnston's Archive
- List of Transneptunian Objects, Minor Planet Center
- 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra at the JPL Small-Body Database
- 469705 ﾇKﾃ｡ﾌｦgﾃ｡ra at AstDyS-2, Asteroids窶妊ynamic Site
Natural satellites of the
Solar System | ||
|---|---|---|
|
Planetary satellites of | | |
|
Dwarf planet satellites of | ||
|
Minor-planet moons | ||
| Ranked by size | ||