3 papers
astro-ph.EP2026
JWST Observations of Asteroid 2024 YR4 Rule Out a 2032 Lunar Impact and Demonstrate a New Regime for Planetary Defense Follow-up
Julien de Wit, Andrew S. Rivkin, Marco Micheli +12
At the end of its discovery apparition, the 60 m near-Earth object 2024 YR4 was associated with a non-zero probability of lunar impact during its 2032 December 22 close appro…
astro-ph.EP2025
Colors and Dynamics of a Near-Sun Orbital Asteroid Family: 2021 PH27 and 2025 GN1
Scott Sheppard, Henry Hsieh, Petr Pokorny +6
We observed the dynamically similar near-Sun asteroids 2021 PH27 and 2025 GN1 for their optical colors. These objects have the lowest known semi-major axes of any asteroids. 2021 P…
astro-ph.EP2024
New Moons of Uranus and Neptune from Ultra-Deep Pencil Beam Surveys
Scott Sheppard, David Tholen, Marina Brozovic +4
We have conducted extremely ultra-deep pencil beam observations for new satellites around both Uranus and Neptune. Tens of images on several different nights in 2021, 2022 and 2023…