arXiv:2505.15806astro-ph.EP
Discovery of a dwarf planet candidate in an extremely wide orbit: 2017 OF201
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 semi-major axis of 830 au and a perihelion of 45 au, precisely determined from 24 observations over 20 years. Assuming a typical albedo of 0.13, we estimate a diameter about 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 about 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.
Here is the arXiv preprint: https://arxiv.org/abs/2505.15806
calmbellView on HNParent context
> and probably out at several 1000 AU at maximum. The preprint announcing the discovery lists the semi-major axis as 838 au, so the major axis is 1676 au and aphelion is about 1630 au. https://arxiv.org/abs/2505.15806
jessriedelView on HNParent context
Well, the preprint announcing the discovery describes its orbit as extending to "the inner Oort cloud" even though aphelion is 1630 au. https://arxiv.org/abs/2505.15806
jessriedelView on HNParent context