(118228) 1996 TQ66

(118228) 1996 TQ₆₆
Discovery
Discovered by	J. Chen; D. C. Jewitt; C. Trujillo; J. X. Luu
Discovery site	Mauna Kea Obs.
Discovery date	8 October 1996
Designations
MPC designation	(118228) 1996 TQ66
Alternative designations	1996 TQ66
Minor planet category	TNO · plutino
Orbital characteristics
	Epoch 1 July 2021 (JD 2459396.5)
	Uncertainty parameter 2
Observation arc	24.17 yr (8,828 d)
Aphelion	44.219 AU
Perihelion	34.535 AU
Semi-major axis	39.377 AU
Eccentricity	0.1230
Orbital period (sidereal)	247.10 yr (90,254 d)
Mean anomaly	33.659°
Mean motion	0° 0m 14.4s / day
Inclination	14.650°
Longitude of ascending node	10.613°
Argument of perihelion	18.541°
Physical characteristics
Mean diameter	185 km (est. at 0.09)
Spectral type	RR (very red); B–V = 1.190±0.020; V–R = 0.660±0.030; V–I = 1.440±0.140;
Apparent magnitude	22.85
Absolute magnitude (H)	7.14

(118228) 1996 TQ₆₆ (provisional designation 1996 TQ₆₆) is a resonant trans-Neptunian object of the plutino population in the Kuiper belt, located in the outermost region of the Solar System. It was discovered on 8 October 1996, by American astronomers Jun Chen, David Jewitt, Chad Trujillo, and Jane Luu, using the UH88 telescope at the Mauna Kea Observatories, Hawaii.^[1]^[2] The very red object measures approximately 185 kilometers (110 miles) in diameter. As of 2021^[update], it has not been named.

Orbit and classification

1996 TQ₆₆ orbits the Sun at a distance of 34.5–44.2 AU once every 247 years and 1 month (90,254 days; semi-major axis of 39.38 AU). Its orbit has an eccentricity of 0.12 and an inclination of 15° with respect to the ecliptic.^[3] The body's observation arc begins with its official discovery observation at the Mauna Kea Observatories on 8 October 1996.^[2] It came to perihelion in 1998. As of 2021^[update], it is at 35.6 AU from the Sun and has an apparent magnitude of 22.85.^[8]

1996 TQ₆₆ is a trans-Neptunian object and belongs to the plutino population,^[4]^[5] a large group of objects named after their largest member, Pluto. These resonant trans-Neptunian objects stay in a 2:3 mean-motion orbital resonance with Neptune, orbiting exactly two times the Sun for every three orbits Neptune does and are therefore protected from Neptune's scattering effect. Plutinos are located in the inner rim of the Kuiper belt, a large circumstellar disc of mostly non-resonant classical Kuiper belt objects.

Numbering and naming

1996 TQ₆₆ was numbered by the Minor Planet Center on 16 November 2005, receiving the number (118228) in the minor planet catalog (M.P.C. 55524).^[9] As of 2021^[update], it has not been named.^[2] According to the established naming conventions, it will be given a mythological name associated with the underworld.^[10]

Physical characteristics

1996 TQ₆₆ has a very red surface color (RR) in the visible part of the spectrum, with B−V and V–R color indices of 1.190±0.020 and 0.660±0.030, respectively, for a combined B−R magnitude of 1.85.^[4]^[6]^[7] A red surface color is typically associated with the presence of tholins, polymer-like organic compounds, formed by long exposures to solar and cosmic radiation.

Rotation period

In 1999, results of a photometric survey of Kuiper belt objects by Romanishin and Tegler were published in the Journal Nature. For 1996 TQ₆₆, a brightness variation of no more than 0.22 in magnitude could be determined, which is indicative of a modestly irregular shape.^[7]^[11] As of 2021^[update], no rotational lightcurve for this object has been obtained from photometry. The body's rotation period, pole and actual shape remain unknown.^[3]^[7]

Diameter and albedo

Based on a generic magnitude-to-diameter conversion, 1996 TQ₆₆ measures approximately 185 kilometers (110 miles) in diameter, for an assumed albedo of 0.9 and an magnitude of 7.^[4]^[12] According to Mike Brown, who estimates a mean-diameter of 186 km (120 mi), the object is too small for being considered a dwarf planet candidate ("probably not").^[13]