| 👁 Image | |
| Discovery[1] | |
|---|---|
| Discovered by | S. S. Sheppard D. J. Tholen C. Trujillo |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 17 February 2021 |
| Designations | |
| 2021 DR15 | |
| 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 |
| 67.171 AU | |
| Eccentricity | 0.4369 |
| 551 yr | |
| 334.122° | |
| 0° 0m 6.445s / day | |
| Inclination | 30.691 |
| 334.122 | |
| 21.846 | |
| Known satellites | 0 |
| Physical characteristics | |
| 530–850 km (for albedo = est. 0.1–0.2)[5]
716 km ? (Assuming an albedo of 0.124)[6] | |
| 0.124 ?[7][a] | |
| 23.2[1] | |
| 3.61±0.15[2] | |
2021 DR15 is a large trans-Neptunian object orbiting the Sun in the scattered disc.
History
[edit]Discovery
[edit]2021 DR15 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.
The discovery was announced on 17 December 2021.[1]
Precovery
[edit]2021 DR15 has been identified in several precovery images as far back as 10 March 2005.[2]
Naming and Numbering
[edit]As of 2026, 2021 DR15 has not been named or even been numbered by the Minor Planet Center yet.[8]
Orbit and observations
[edit]Orbital characteristics
[edit]2021 DR15 orbits the Sun at a distance of 37.8–96.5 AU with an semi-major axis or average orbital distance of 67.2 AU once every 551 years (for reference, Neptune's orbit is at 30 AU).[4][9]
Its orbit has a relatively high eccentricity of 0.437 and an inclination of 30.7° with respect to the ecliptic.[2][4]
Observations
[edit]It was 89.4 astronomical units (AU) 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].[3]
Classification
[edit]2021 DR15 belongs to the scattered disc,[3] which is a population of TNOs that have distant, inclined, and eccentric orbits that come close to Neptune at perihelion.
The scattered disc population, which includes the dwarf planets Eris and Gonggong, are strongly influenced by Neptune's gravitational perturbations and consequently experience gravitational scattering.[10]: 52
The Minor Planet Center also classifies 2021 DR15 as a scattered disc object.[3]
Physical characteristics
[edit]Size, brightness
[edit]Based on its absolute magnitude of 3.61±0.15,[2] it may be the brightest known object in the Solar System that does not have a directly measured size.
Its diameter is estimated to be between 530 to 850 kilometres (330 to 530 miles), assuming a typical trans-Neptunian object's albedo of 0.1–0.2.[5]
Size estimate by Johnston's archive
[edit]Johnston's Archive gives a diameter of 716 kilometres for the 2021 DR15, under the assumption of it having an albedo of 0.124, which is generally what he assumes for scattered disc objects.[11]
Density theory
[edit]Based on its size of 530–850 km,[5] 2021 DR15 belongs to the proposed class of "mid-sized" TNOs between 400 and 1,000 km (250 and 620 mi) in diameter, which are believed to represent the transition between small, low-density TNOs and large, high-density dwarf planets.[12][13]: 1
Planetary scientists have hypothesized that mid-sized TNOs should theoretically have highly porous and unheated interiors, because TNOs in this size range (namely Uni and Gǃkúnǁʼhòmdímà) have been found to have low densities of around 1 g/cm3.[12]
Upcoming observations
[edit]2021 DR15 has not been imaged by high-resolution telescopes yet, so it does not have any known natural satellites or moons,[14] which means there is currently no way to measure its mass and density.[15]: 1, 3
The Hubble Space Telescope is planned to image 2021 DR15 in 2026, which should determine if it has any significantly sized moons.[14]
See also
[edit]- List of possible dwarf planets
- 2014 UZ224 – large scattered disc object and a possible dwarf planet
- 2017 OF201 – extreme scattered disc object and a possible dwarf planet
- 532037 Chiminigagua - large scattered disc object and a possible dwarf planet
- List of Solar System objects by size
- List of Solar System objects most distant from the Sun
Notes
[edit]- ^ Johnston's archive usually estimates an albedo of 0.124 for scattered disc objects like 2021 DR15
References
[edit]- ^ a b c "MPEC 2021-Y28 : 2021 DR15". Minor Planet Electronic Circular. Minor Planet Center. 17 December 2021. Retrieved 17 December 2021.
- ^ a b c d e "JPL Small-Body Database Browser: (2021 DR15)" (2021-12-06 last obs.). Jet Propulsion Laboratory. Retrieved 17 December 2021.
- ^ a b c d "List Of Centaurs and Scattered-Disk Objects". Minor Planet Center. International Astronomical Union. Retrieved 17 December 2021.
- ^ a b c d "2021 DR15". Minor Planet Center. International Astronomical Union. Retrieved 17 December 2021.
- ^ a b c "Asteroid Size Estimator". Center for Near Earth Object Studies. Jet Propulsion Laboratory. Retrieved 17 December 2021.
- ^ "List of known trans-Neptunian objects". www.johnstonsarchive.net. Retrieved 14 January 2026.
- ^ "List of known trans-Neptunian objects". www.johnstonsarchive.net. Retrieved 14 January 2026.
- ^ "JPL Small-Body Database Browser: (2021 DR15)". JPL Small-Body Database. Jet Propulsion Laboratory.
- ^ Yeomans, Donald K. "HORIZONS Web-Interface for Neptune Barycenter (Major Body=8)". JPL Horizons On-Line Ephemeris System. Archived from the original on 7 September 2021. Retrieved 18 July 2014.—Select "Ephemeris Type: Orbital Elements", "Time Span: 2000-01-01 12:00 to 2000-01-02". ("Target Body: Neptune Barycenter" and "Center: Solar System Barycenter (@0)".)
- ^ Gladman, Brett; Marsden, Brian G.; VanLaerhoven, Christa (2008). "Nomenclature in the Outer Solar System" (PDF). The Solar System Beyond Neptune. University of Arizona Press. pp. 43–57. arXiv:astro-ph/0702538. Bibcode:2008ssbn.book...43G. ISBN 9780816527557. S2CID 14469199. Archived from the original (PDF) on 1 August 2023.
- ^ "List of known trans-Neptunian objects". www.johnstonsarchive.net. Retrieved 14 January 2026.
- ^ a b Grundy, W. M.; Noll, K. S.; Buie, M. W.; Benecchi, S. D.; Ragozzine, D.; Roe, H. G. (December 2019). "The Mutual Orbit, Mass, and Density of Transneptunian Binary Gǃkúnǁʼhòmdímà ((229762) 2007 UK126)" (PDF). Icarus. 334: 30–38. Bibcode:2019Icar..334...30G. doi:10.1016/j.icarus.2018.12.037. S2CID 126574999.
- ^ Sheppard, Scott; Fernandez, Yanga; Moullet, Arielle (6 September 2018). "The Albedos, Sizes, Colors and Satellites of Dwarf Planets Compared with Newly Measured Dwarf Planet 2013 FY27". The Astronomical Journal. 156 (6): 270. arXiv:1809.02184. Bibcode:2018AJ....156..270S. doi:10.3847/1538-3881/aae92a. S2CID 119522310.
- ^ a b Proudfoot, Benjamin (August 2025). "A Search For The Moons of Mid-Sized TNOs". Mikulski Archive for Space Telescopes. Space Telescope Science Institute: HST Proposal 18010. Cycle 33. Retrieved 17 August 2025.
- ^ Grundy, W. M.; McKinnon, W. B.; Ammannito, E.; Aung, M.; Bellerose, J.; Brenker, F.; et al. (December 2009). Exploration Strategy for the Ice Dwarf Planets 2013-2022 (PDF). American Geophysical Union Fall Meeting 2009. Bibcode:2009AGUFM.P43D1471G. P43D-1471. Archived from the original (PDF) on 30 March 2025.
External links
[edit]- 2021 DR15 at AstDyS-2, Asteroids—Dynamic Site
- 2021 DR15 at the JPL Small-Body Database
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