2021 DR15

2021 DR₁₅ is a large trans-Neptunian object in the scattered disc, estimated to be around 600 to 800 kilometres (400 to 500 miles) in diameter. It was discovered on 17 February 2021, by American astronomers Scott Sheppard, David Tholen, and Chad Trujillo using the 8.2-meter Subaru Telescope of the Mauna Kea Observatories in Hawaii, and announced on 17 December 2021.^[1] With an absolute magnitude of between 3.4 and 3.8, it may be the brightest known object in the Solar System that does not have a directly measured size. It was 89.4 astronomical units from the Sun when it was discovered, making it the ninth-most distant known Solar System object from the Sun as of December 2021^[update].^[1] It has been identified in several precovery images as far back as 10 March 2005.^[2]

2021 DR₁₅

2021 DR15 imaged by Cerro Tololo Observatory's Dark Energy Camera on 30 April 2013
Discovery[1]
Discovered by	S. S. Sheppard D. J. Tholen C. Trujillo
Discovery site	Mauna Kea Obs.
Discovery date	17 February 2021
Designations
MPC designation	2021 DR15
Minor planet category	TNO[2] · SDO[3] · distant[4]
Orbital characteristics[4]
Epoch 21 January 2022 (JD 2459600.5)
Uncertainty parameter 5
Observation arc	16.74 yr (6,115 days)
Earliest precovery date	10 March 2005
Aphelion	96.518 AU
Perihelion	37.824 AU
Semi-major axis	67.171 AU
Eccentricity	0.4369
Orbital period (sidereal)	551 yr
Mean anomaly	334.122°
Mean motion	0° 0m 6.445s / day
Inclination	30.691
Longitude of ascending node	334.122
Argument of perihelion	21.846
Physical characteristics
Mean diameter	530–850 km (for albedo = est. 0.1–0.2)[5]
Apparent magnitude	23.2[1]
Absolute magnitude (H)	3.61±0.15[2]

2021 DR₁₅ has not yet been imaged by high-resolution telescopes, so it has no known moons.^[6] The Hubble Space Telescope is planned to image 2021 DR₁₅ in 2026, which should determine if it has significantly sized moons.^[6]

See also

• List of possible dwarf planets
  • 2014 UZ224 – large scattered disc object and dwarf planet candidate
  • 2017 OF201 – extreme scattered disc object and dwarf planet candidate
• List of Solar System objects by size
• List of Solar System objects most distant from the Sun