Overview

• A preprint led by Amir Siraj proposes a Mercury-to-Earth–mass planet at roughly 100–200 astronomical units to explain a measured tilt in distant Kuiper belt orbits.
• The team finds the mean orbital plane of objects about 80–400 AU from the Sun appears warped by roughly 15 degrees relative to the solar system’s plane.
• The authors characterize the evidence as tentative, estimating a 2–4% chance the signal is a statistical fluke and noting no direct detection of the planet.
• The paper is posted on arXiv and, according to the authors, has been accepted for publication in Monthly Notices of the Royal Astronomical Society.
• Upcoming observations from the Vera C. Rubin Observatory’s LSST are expected to rapidly expand the TNO catalog and could confirm or refute the warp within the survey’s first few years.