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 […]
3I/ATLAS
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.
Posted inAstrochemistry, Astrogeology, Comets and Asteroids, Icy Worlds, Interstellar, Missions & Hardware, Press Release
SwRI-proposed Mission Could Encounter And Explore A Future Interstellar Comet Like3I/ATLAS Up Close
Southwest Research Institute (SwRI) has completed a mission study detailing how a proposed spacecraft could fly by an interstellar comet, providing remarkable insights into the properties of bodies originating beyond […]
![CN production versus heliocentric distance: Blue circles show VLT/X-shooter measurements of 3I/ATLAS (this work); the black solid and gray dashed curves are power–law fits to the 3I data only, giving Q(CN) ∝ r −9.38±1.2 h (weighted) and Q(CN) ∝ r −9.14±1.57 h (unweighted), respectively. Colored symbols compare with Solar–system comets compiled from the literature, grouped by dynamical class as in the legend; green squares mark measurements for 2I/Borisov. The left axis gives log10[Q(CN)/atoms s−1 ] and the bottom axis in log-scale the heliocentric distance rh (au). The right axis shows an approximate equilibrium surface temperature T(rh). Horizontal dashed lines indicate sublimation thresholds for CO, NH3, CO2, and H2O. Other comets references: Manfroid et al. (2021), Opitom et al. (2016), Opitom et al. (2017), Opitom et al. (2019), Fitzsimmons et al. (2019), Rauer et al. (2003) and S -- astro-ph.SR](https://i0.wp.com/astrobiology.com/wp-content/uploads/2025/08/VLT-Observations-Of-Interstellar.png?resize=1200%2C785&ssl=1)
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report
VLT Observations Of Interstellar Comet 3I/ATLAS II. From quiescence To Glow: Dramatic Rise Of Ni I Emission And Incipient CN Outgassing At Large Heliocentric Distances
We report VLT spectroscopy of the interstellar comet 3I/ATLAS (C/2025 N1) from rh≃4.4 to 2.85 au using X-shooter (300-550 nm, R≃3000) and UVES (optical, R≃35k−80k).
Posted inAstrochemistry, Astrogeology, Astronomy & Telescopes, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Status Report
JWST Detection Of A Carbon Dioxide Dominated Gas Coma Surrounding Interstellar Object 3I/ATLAS
3I/ATLAS is the third confirmed interstellar object to visit our Solar System, and only the second to display a clear coma.
Posted inComets and Asteroids, Imaging & Spectroscopy, Intelligence & Language, Interstellar, SETI & Technosignatures, Status Report
Technosignature Searches Of Interstellar Objects
With the discovery of the third confirmed interstellar object (ISO), 3I/ATLAS, we have entered a new phase in the exploration of these long-predicted objects.