5 papers
Astrometric follow-up of near-Earth asteroid 2024 YR4 during a Torino scale level 3 alert
Marco Micheli, Maxime Devogèle, Larry Denneau +38
The discovery of 2024 YR4 presented the planetary defense community with the most significant impact threat in almost two decades, reaching level 3 on the Torino scale. The communi…
Dynamically New Comet C/2025 D1 (Groeller) with Record Perihelion Distance
Man-To Hui, Robert Weryk, Marco Micheli +5
We studied C/2025 D1 (Groeller), a long-period comet with an unprecedented perihelion distance of 14.1 au, using archival observations. The data reveals that it had been active at…
Discovery and Preliminary Characterization of a Third Interstellar Object: 3I/ATLAS
Darryl Z. Seligman, Marco Micheli, Davide Farnocchia +44
We report initial observations aimed at the characterization of a third interstellar object. This object, 3I/ATLAS or C/2025 N1 (ATLAS), was discovered on 2025 July 1 UT and has an…
A limit on the mass of the Taurid Resonant Swarm at sub-100 meter sizes
Paul Wiegert, Denis Vida, David L. Clark +3
We report on a pencil-beam survey of the Taurid Swarm, a possible concentration of bodies in the Taurid meteoroid stream associated with the 7:2 mean-motion resonance with Jupiter.…
2019 UO: A Transient Trojan of Saturn
Man-To Hui, Paul A. Wiegert, Robert Weryk +5
Saturn has long been the only giant planet in our solar system without any known Trojan members. In this paper, with serendipitous archival observations and refined orbit determina…