Asteroid Terrestrial-impact Last Alert System (ATLAS) Archives

[TOP] Example observations of (2060) Chiron for survey/telescopes (left) ATLAS, (middle) ZTF, and (right) LCO/LOOK. [BOTTOM] Example observations of 103P/Hartley 2 for survey/telescopes (left) ATLAS, (middle) ZTF, and (right) LCO/LOOK. -- astro-ph.EP

Comets and Asteroids

Multi-year Ground-Based Survey Photometry of Active Comet 103P/Hartley 2 and Centaur (2060) Chiron: A Tale of Two Comets in the Pre-LSST Era

by Keith CowingJuly 5, 2026July 5, 2026

[astro-ph.EP] Comets and Centaurs trace the evolution of trans-Neptunian objects (TNOs) into the inner solar system.

Interstellar Comet 3I/ATLAS (NIRSpec IFU) -- ESA (larger Image)

Comets and Asteroids

Webb Finds Clues To The Ancient Origin Of Comet 3I/ATLAS

by Keith CowingJune 23, 2026June 23, 2026

The third identified interstellar comet in human history has a surprising chemical makeup, raising questions as to how common, or unusual, conditions in our own Solar System may be.

Distribution of hits (circles) and events (stars) over frequency and drift rate. The marker size gives the S/N. The gray-shaded regions show ranges not sampled, including narrow notch filter regions in the L and S bands. The color-shaded regions give the range of drift rates expected from Earth’s orbital motion and rotational motion and 3I/ATLAS’s rotation at each of the four observing bands. These regions do not perfectly align between bands due to 3I/ATLAS’s radial acceleration changing during overhead time between observations. No events lie in the expected drift rate regions. -- astro-ph.IM

Astronomy & Telescopes, Comets and Asteroids, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report

Breakthrough Listen Observations Of 3I/ATLAS With The Green Bank Telescope at 1-12 GHz

by Keith CowingDecember 31, 2025December 31, 2025

3I/ATLAS (also designated C/2025 N1 (ATLAS) and, formerly, A11pl3Z) is the third interstellar object (ISO), following 1I/‘Oumuamua and 2I/Borisov, to be discovered during a passage through the Solar System. The […]