(469306) 1999 CD158

(469306) 1999 CD₁₅₈ (provisional designation 1999 CD₁₅₈) is a resonant trans-Neptunian object from the circumstellar disc of the Kuiper belt, located in the outermost region of the Solar System. It measures approximately 310 kilometers (190 miles) in diameter. It was discovered on 10 February 1999, by American astronomers Jane Luu, David Jewitt, and Chad Trujillo at Mauna Kea Observatories on the Big Island of Hawaii, United States.^[3]

(469306) 1999 CD₁₅₈

Discovery[1]
Discovered by	J. X. Luu D. C. Jewitt C. Trujillo
Discovery site	Mauna Kea Obs.
Discovery date	10 February 1999
Designations
MPC designation	(469306) 1999 CD158
Alternative designations	1999 CD158
Minor planet category	TNO[1] · res 4:7?[2] distant[3] · detached[4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 3
Observation arc	16.18 yr (5,908 days)
Aphelion	50.139 AU
Perihelion	37.410 AU
Semi-major axis	43.775 AU
Eccentricity	0.1454
Orbital period (sidereal)	289.63 yr (105,787 days)
Mean anomaly	250.48°
Mean motion	0° 0m 12.24s / day
Inclination	25.486°
Longitude of ascending node	119.03°
Time of perihelion	≈ 17 February 2107[5] ±3 days
Argument of perihelion	143.51°
Physical characteristics
Mean diameter	310 km[2]
Synodic rotation period	6.88±0.02 h[6]
Geometric albedo	0.13[2]
Spectral type	IR[2][7] · C[8] B–V = 0.770[9] · 0.830[10] · 0.864[11] · 0.860[7] V–R = 0.630[9] · 0.510[10] · 0.520[11] · 0.520[7] V–I = 1.110[9] · 1.092[11] · 1.100[7]
Apparent magnitude	21.8[12]
Absolute magnitude (H)	4.837±0.111 (R)[13] · 5.28[1][3]

Orbit and classification

1999 CD₁₅₈ is a candidate member of the Haumea family, the only collisional group of trans-Neptunian objects currently determined.^[6] It is also sub-classified as a resonant trans-Neptunian object, as it stays in a 4:7 orbital resonance with the ice giant Neptune, which means, that for every seven orbits of Neptune around the Sun, it makes four orbits. It orbits the Sun at a distance of 37.4–50.1 AU once every 289 years and 8 months (105,787 days). Its orbit has an eccentricity of 0.15 and an inclination of 25° with respect to the ecliptic.^[1]

Its observation arc begins with its official discovery observation at Mauna Kea in 1999, as no precovery images were taken and no prior identifications were made.^[3] As of 2017 its current position is at 46.7 AU from the Sun.^[14]

Physical characteristics

Photometry

Photometric observation of 1999 CD₁₅₈ in March 2015, gave a classically shaped bimodal lightcurve with a rotation period of 6.88 hours and a large brightness variation of 0.49 magnitude (U=3-).^[6]

Observations with the New Technology Telescope at ESO's La Silla Observatory in Chile in 2008, determined the body's BVRI colors to be 0.770 (B–V), 0.630 (V–R), and 1.110 (V–I) for their respective passbands.^[9] Color indices have since been repeatedly measured.^[8]

Diameter and albedo

According to estimates by Johnston's Archive, the Collaborative Asteroid Lightcurve Link, and American astronomer Michael Brown, 1999 CD₁₅₈ measures between 420 and 477 kilometers in diameter.^[8][2][15] It is "probably" a dwarf planet according to Brown's assessment (see List of possible dwarf planets § list).^[15]

Naming

As of 2025, this minor planet remains unnamed.^[3]