Discovery of a Dwarf Planet Candidate in an Extremely Wide Orbit: 2017 OF201
Abstract
Abstract We report the discovery of a dwarf planet candidate, 2017 OF201, currently located at a distance of 90 au. Its orbit is extremely wide and extends to the inner Oort cloud, with a semimajor axis of 830 au and a perihelion of 45 au, precisely determined from 24 observations over 20 yr. Assuming a typical albedo of 0.13, we estimate a diameter ∼700 km, making it the second-largest known object in this dynamical population and a dwarf planet candidate with the widest orbit. Its high eccentricity suggests that an unseen population of similar objects would total ∼1% of Earth’s mass. Notably, the longitude of perihelion of 2017 OF201 lies outside the clustering observed in extreme trans-Neptunian objects, posing a challenge to the proposed dynamical evidence for the hypothetical Planet Nine.
Fields of Study & Subjects
Astro and Planetary Science
Stellar
planetary
and galactic studies
Gamma-ray bursts and supernovae
Publication details
- Journal / source
- The Astrophysical Journal Letters
- Publisher
- American Astronomical Society
- Volume
- 998
- Issue
- 1
- Pages
- L6–L6
- Publication date
- 3 February 2026
- Language
- EN