2026 ED138

2026 ED138
Snapshots of 2026 ED138 by the Vera C. Rubin Observatory from March–July 2026
Discovery
Discovered byMatthew J. Holman
Discovery siteSimonyi Survey Telescope (Vera C. Rubin Observatory)
Discovery date
  • 4 March 2026 (first obs.)
  • 13 October 2026 (recognition)
Designations
Orbital characteristics
Epoch 9 June 2026 (JD 2461200.5)
Uncertainty parameter 4
Observation arc10.37 yr (3,789 d)
Earliest precovery date25 February 2016
Aphelion49.036 AU
Perihelion36.861 AU
42.949 AU
Eccentricity0.1417
281 yr
128.336°
0° 0m 12.606s/day
Inclination24.471°
322.501°
4 February 1926
167.952°
Physical characteristics
600~1500 km
2.92±0.16

2026 ED138 is a large trans-Neptunian object and possible dwarf planet in the Kuiper belt. It was discovered by Matthew Holman on 13 October 2026, while searching through Vera C. Rubin Observatory data taken earlier that year. It has an absolute magnitude between 2.8 and 3.1, making it as bright as the dwarf planet candidates Quaoar or Chiminigagua. The brightness of 2026 ED138 implies that it has a diameter between 600 and 1,500 kilometers (370 and 930 mi), making it among the largest known dwarf planet candidates.

Discovery

2026 ED138 was discovered by Matthew Holman on 13 October 2026, while searching through Vera C. Rubin Observatory data taken earlier that year. The search made use of a computer program that Holman co-developed with Kevin Napier to automatically identify moving objects in images. Upon discovering 2026 ED138, Holman recognized the object's unusually large size and brightness and prompted further searches of earlier images. Mario Jurić uncovered 20 more Rubin images of 2026 ED138 going back to 4 March 2026, while the B612 Asteroid Institute uncovered even earlier observations taken by the Cerro Tololo Inter-American Observatory's Dark Energy Camera (DECam) from 2016–2019. With over 10 years of collected observations, the Minor Planet Center and the Vera C. Rubin Observatory team jointly announced the discovery of 2026 ED138 on 27 October 2026.

Name

2026 ED138 is the provisional designation of this object, given by the Minor Planet Center upon announcing its discovery. The provisional designation includes the year of the object's discovery (2026), the half-month of its discovery date (E = first half of March), and the order of its discovery after other minor planets found during this half-month (D138 = 3,454th minor planet discovered). According to the Minor Planet Center, minor planets eventually receive a permanent catalog number once their orbits are sufficiently known and have been extensively observed over several years. It is only after this point that minor planets can be named.

2026 ED138 is considered a classical trans-Neptunian object. According to the International Astronomical Union, these types of objects must be given mythological names, preferably those associated with creation myths.

Orbit

Diagram showing the orbits of 2026 ED138 (blue) and the other dwarf planets (yellow)

As of October 2026, it is at a distance of roughly 46 AU from the Sun.

References

  1. 1 2 3 4 "2026 ED138". Minor Planet Center. Retrieved 27 October 2026.
  2. 1 2 3 4 5 6 7 8 9 10 11 "NSF–DOE Vera C. Rubin Observatory Reveals Its First Dwarf Planet Candidate in Our Solar System". Vera C. Rubin Observatory. 27 October 2026. Retrieved 27 October 2026.
  3. 1 2 "JPL Small-Body Database Browser: (2026 ED138)" (2026-07-11 last obs.). Jet Propulsion Laboratory. Retrieved 28 October 2026.
  4. 1 2 3 "MPEC 2026-U85 : 2026 ED138". Minor Planet Electronic Circular. 2026-U85. Minor Planet Center. 27 October 2026. Retrieved 28 October 2026.
  5. ↑ "New- And Old-Style Minor Planet Designations". Minor Planet Center. Archived from the original on 6 May 2021. Retrieved 28 October 2026.
  6. ↑ "Guide to Minor Body Astrometry". Minor Planet Center. Retrieved 28 October 2026. {{cite web}}: |chapter= ignored (help)
  7. 1 2 "Rules and Guidelines for Naming Non-Cometary Small Solar-System Bodies" (PDF). IAU Working Group for Small Bodies Nomenclature. 22 February 2025. Archived (PDF) from the original on 20 March 2023. Retrieved 27 October 2026.