We analyze polarimetric measurements of the interstellar Comet 3I/ATLAS reported recently by Z. Gray et al. Comparison with distant solar system comets suggests no significant difference in the microphysics of […]
3I/ATLAS
Posted inAstrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release
Astrochemistry: Physicists Uncork A Message In A Bottle From Another Star
For millions of years, a fragment of ice and dust drifted between the stars—like a sealed bottle cast into the cosmic ocean. This summer, that bottle finally washed ashore in […]
Posted inAstrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release
ExoMars And Mars Express Observe Interstellar Comet 3I/ATLAS
Between 1 and 7 October, ESA’s ExoMars Trace Gas Orbiter (TGO) and Mars Express spacecraft turned their eyes towards interstellar comet 3I/ATLAS, as it passed close to Mars.
![Continuum-subtracted spectra of comet 3I obtained on August 28 and September 3+4. Three narrow FeI lines are detected on August 28 in this spectral range, FeI λ3719.93Å being the brightest iron line detected in our spectra. On the average spectrum obtained in September 3+4 (shifted vertically for clarity), the FeI lines are brighter, and four of them are detected. Broad emission features due to background [OII] emission at 3727Å and 3729Å are also observed. -- astro-ph.EP](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/10/Extreme-NiIFeI.png?resize=1200%2C742&ssl=1)
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Status Report
Extreme NiI/FeI Abundance Ratio In The Coma Of The Interstellar Comet 3I/ATLAS
Emission lines of FeI and NiI are commonly found in the coma of solar system comets, even at large heliocentric distances.
Posted inAstrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Comets and Asteroids, Interstellar, Status Report
Prediscovery Activity of New Interstellar Object 3I/ATLAS: A Dynamically-Old Comet?
We report on the prediscovery observations and constraints of the new interstellar comet 3I/2025 N1 (ATLAS), made by the Zwicky Transient Facility (ZTF), for the inbound leg of the comet […]
Posted inAstronomy & Telescopes, Comets and Asteroids, Imaging & Spectroscopy, Interstellar, Status Report
3I/ATLAS: In Search Of The Witnesses To Its Voyage
3I/ATLAS is the third interstellar object discovered to date, following 1I/’Oumuamua and 2I/Borisov.
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release
Extreme Negative Polarisation of New Interstellar Comet 3I/ATLAS
We present the first polarimetric observations of the third discovered interstellar object, 3I/ATLAS (C/2025 N1), obtained pre-perihelion with FORS2/VLT, ALFOSC/NOT, and FoReRo2/RCC, over a phase angle range of 7.7-22.4°.
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report
Search For Past Stellar Encounters And The Origin Of 3I/ATLAS
3I/ATLAS, the third discovered interstellar object, has a heliocentric speed of 58 km/s and exhibits cometary activity.
Posted inAstronomy & Telescopes, Comets and Asteroids, Interstellar, Status Report
Near-Discovery SOAR Photometry of the Third Interstellar Object: 3I/ATLAS
3I/ATLAS was discovered on UT 2025 July 1 and joins a limited but growing population of detected ∼102−103 m scale interstellar objects.
Posted inAstrochemistry, Astronomy & Telescopes, Biosignatures & Paleobiology, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report
Onset of CN Emission in 3I/ATLAS: Evidence for Strong Carbon-Chain Depletion
Interstellar objects provide a direct window into the environmental conditions around stars other than the Sun.