120347 Salacia

120347 Salacia
	Keck Telescope image of Salacia (bright, center) and its moon Actaea (faint, at left)
Discovery
Discovered by	H. G. Roe; M. E. Brown; K. M. Barkume
Discovery site	Palomar Obs.
Discovery date	22 September 2004
Designations
MPC designation	(120347) Salacia
Pronunciation	/səˈleɪʃə/ (sə-LAY-shə)
Named after	Salacia (Roman mythology)
Alternative designations	2004 SB60
Minor planet category	TNO · Cubewano; Extended
Adjectives	Salacian
Symbol	or
Orbital characteristics
	Epoch 31 May 2020 (JD 2459000.5)
	Uncertainty parameter 3
Observation arc	37.16 yr (13,572 days)
Earliest precovery date	25 July 1982
Aphelion	46.670 AU
Perihelion	37.697 AU
Semi-major axis	42.184 AU
Eccentricity	0.10636
Orbital period (sidereal)	273.98 yr (100,073 days)
Mean anomaly	123.138°
Mean motion	0° 0m 12.951s / day
Inclination	23.921°
Longitude of ascending node	279.880°
Argument of perihelion	312.294°
Known satellites	1 (Actaea)
Physical characteristics
Mean diameter	846±21 km; 854±45 km (equal albedos); 866±37 km
Mass	(4.922±0.071)×1020 kg (system); (4.38±0.16)×1020 kg (system mass)
Mean density	1.5±0.12 g/cm3; 1.29+0.29; −0.23 g/cm3 (system); 1.26±0.16 g/cm3
Synodic rotation period	6.09 h (0.254 d)
Sidereal rotation period	6.09 h
Geometric albedo	0.044±0.004; 0.042±0.004
Spectral type	BB; B−V=0.66±0.06; V−R=0.40±0.04; V−I=0.83±0.04
Apparent magnitude	20.7
Absolute magnitude (H)	4.360±0.011 (system); 4.476±0.013 (Salacia); 6.850±0.053 (Actaea); 3.9

Salacia (minor-planet designation: 120347 Salacia) is a large trans-Neptunian object in the Kuiper belt, approximately 850 km (530 mi) in diameter. It was discovered on 22 September 2004, by American astronomers Henry Roe, Michael Brown and Kristina Barkume at the Palomar Observatory in California, United States. Salacia orbits the Sun at an average distance that is slightly greater than that of Pluto. It was named after the Roman goddess Salacia and has a single known moon, Actaea.

Brown estimated that Salacia is nearly certainly a dwarf planet.^[10] However, William Grundy et al. argue that objects in the size range of 400–1,000 km, with densities of ≈ 1.2 g/cm³ or less and albedos less than ≈ 0.2, have likely never compressed into fully solid bodies or been resurfaced, let alone differentiated or collapsed into hydrostatic equilibrium, and so are highly unlikely to be dwarf planets.^[11] Salacia is at the upper end of this size range and has a very low albedo, though Grundy et al. later found it to have the relatively high density of 1.5±0.1 g/cm³.^[5]

^ ^a ^b ^c ^d ^e Cite error: The named reference jpldata was invoked but never defined (see the help page).
^ ^a ^b Cite error: The named reference MPC-Salacia was invoked but never defined (see the help page).
^ Cite error: The named reference MPEC 2009-R09 was invoked but never defined (see the help page).
^ Cite error: The named reference Buie was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference Grundy-orbits was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference TNOsCool8 was invoked but never defined (see the help page).
^ ^a ^b ^c Cite error: The named reference Brown2017 was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference Stansberry-result was invoked but never defined (see the help page).
^ ^a ^b ^c ^d Cite error: The named reference Belskaya2015 was invoked but never defined (see the help page).
^ Cite error: The named reference Brown-dplist was invoked but never defined (see the help page).
^ W.M. Grundy, K.S. Noll, M.W. Buie, S.D. Benecchi, D. Ragozzine & H.G. Roe, 'The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK₁₂₆)', Icarus (forthcoming, available online 30 March 2019) Archived 7 April 2019 at the Wayback Machine DOI: 10.1016/j.icarus.2018.12.037,

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[Grundy2019-12] W.M. Grundy, K.S. Noll, M.W. Buie, S.D. Benecchi, D. Ragozzine & H.G. Roe, 'The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK₁₂₆)', Icarus (forthcoming, available online 30 March 2019) Archived 7 April 2019 at the Wayback Machine DOI: 10.1016/j.icarus.2018.12.037,

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Discovery^[1]^[2]
Keck Telescope image of Salacia (bright, center) and its moon Actaea (faint, at left)
Discovered by	H. G. Roe M. E. Brown K. M. Barkume
Discovery site	Palomar Obs.
Discovery date	22 September 2004
Designations
MPC designation	(120347) Salacia
Pronunciation	/səˈleɪʃə/ (sə-LAY-shə)
Named after	Salacia (Roman mythology)^[2]
Alternative designations	2004 SB₆₀
Minor planet category	TNO^[1] · Cubewano^[3] Extended^[4]
Adjectives	Salacian
Symbol	or
Orbital characteristics^[1]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 3
Observation arc	37.16 yr (13,572 days)
Earliest precovery date	25 July 1982
Aphelion	46.670 AU
Perihelion	37.697 AU
Semi-major axis	42.184 AU
Eccentricity	0.10636
Orbital period (sidereal)	273.98 yr (100,073 days)
Mean anomaly	123.138°
Mean motion	0° 0^m 12.951^s / day
Inclination	23.921°
Longitude of ascending node	279.880°
Argument of perihelion	312.294°
Known satellites	1 (Actaea)
Physical characteristics
Mean diameter	846±21 km^[5]^[a] 854±45 km (equal albedos)^[6] 866±37 km^[7]
Mass	(4.922±0.071)×10²⁰ kg (system)^[5] (4.38±0.16)×10²⁰ kg (system mass)^[6]^[8]
Mean density	1.5±0.12 g/cm³^[5] 1.29+0.29 −0.23 g/cm³ (system)^[6] 1.26±0.16 g/cm³^[7]
Synodic rotation period	6.09 h (0.254 d)
Sidereal rotation period	6.09 h^[1]
Geometric albedo	0.044±0.004^[6] 0.042±0.004^[7]
Spectral type	BB^[9] B−V=0.66±0.06^[9] V−R=0.40±0.04^[9] V−I=0.83±0.04^[9]
Apparent magnitude	20.7
Absolute magnitude (H)	4.360±0.011 (system)^[8] 4.476±0.013 (Salacia)^[8] 6.850±0.053 (Actaea)^[8] 3.9^[1]