The Mars-crossing Asteroid that was Actually a Comet: Citizen Science and AI Reveal Activity from (446816) 2000 EE38
Year: 2026
Type: article
Abstract: We report the discovery of a long, diffuse tail from Mars-crossing minor planet (446816) 2000 EE 38 . This discovery was made by the AI assistant “ TailNet ” for our Citizen science projects Active Asteroids and Rubin Comet Catchers , which scored 2000 EE 38 a very low inactivity score. The 44 images displaying unambiguous activity, all from the Canada–France–Hawaii Telescope MegaPrime camera, were identified through our archival investigation of over 1500 images spanning UT 2016 January 31 to UT 2016 May 10, when 2000 EE 38 was at true anomaly angles ranging from 301 ∘ < f < 357 ∘ . 2000 EE 38 crosses the orbit of Mars and has encounters within <0.5 au of Earth. Although it has a Tisserand Parameter with respect to Jupiter T J = 3.005, slightly above the nominal T J = 3.0 asteroid–comet boundary, we classify 2000 EE 38 as a Jupiter-family comet due to the nature of its orbit, including close approaches to Jupiter.
Source: Research Notes of the AAS
Authors: Naomi Morato, Colin Orion Chandler, Nima Sedaghat, William J. Oldroyd, Joseph Murtagh, Dmitrii Vavilov, Richard Wainscoat, Karen Meech, Marco Micheli, Robert Weryk, Maxwell K. Frissell, Henry H. Hsieh, Chadwick A. Trujillo, William A. Burris, Jay K. Kueny, Devanshi Singh, Jinshuo Zhang, Kennedy A. Farrell, Jarod A. DeSpain, Mark Jesus Mendoza Magbanua, Scott S. Sheppard, Michele T. Mazzucato, Milton K. D. Bosch, Tiffany Rindler, Virgilio Gonano, Al Lamperti, José A. da Silva Campos, Brian L. Goodwin, Ivan A. Terentev, Charles J. A. Dukes, Antonio Pasqua
Institutions: University of Washington, Northern Arizona University, Institute of Astronomy, European Space Agency, Western University, Planetary Science Institute, Institute of Astronomy and Astrophysics, Academia Sinica, University of Arizona, Lowell Observatory, University of California, San Francisco, Carnegie Institution for Science, Royal Astronomical Society
Topic: Astro and Planetary Science
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7170695065