[astro-ph.EP] We present multiband, long-baseline photometric observations of interstellar comet 3I throughout its 2025–2026 apparition using coordinated ground-based global relay observations.
3I/ATLAS
![Sky-coverage of the four surveys utilized in this study, with celestial coordinates displayed. It depicts three consecutive observation sectors of TESS, labeled as i−1, i, and i+1. Each of the four TESS cameras is represented by a different color. The beginning of each sector is marked in gray at an ecliptic latitude of 6 deg. The green area indicates the observing region of the fourth camera, which begins at an ecliptic latitude of 78 deg and encompasses the entire ecliptic pole. The magenta, yellow, and grey areas depict the typical 15-day observation coverage of LSST, Pan-STARRS, and ATLAS-W68, respectively. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/1IOumuamua.png?resize=1200%2C717&ssl=1)
Posted inInterstellar
1I/’Oumuamua-like Objects’s SFDs With Older, Current And Future Surveys
[astro-ph.EP] Interstellar Objects (ISOs) may provide direct evidence of planetesimals ejected from early-stage solar systems. Studying these objects and predicting their detection through various surveys is vital for enhancing our […]
![Temporal evolution of selected species and D/H ratios during the cloud (top panels) and core stages (lower panels). Panels (a) and (e) show the abundances of selected species during the cloud and core stages, respectively. Solid, dashed, and dotted lines denote models with Z = 1, 0.5, and 0.2, respectively. The remaining panels show the temporal evolution of the D/H ratios and the H2 OPR for Z = 1 (b, f), Z = 0.5 (c, g), and Z = 0.2 (d, h). In all panels, time is normalized by τfreeze for the corresponding density and metallicity. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/High-water.png?resize=1200%2C719&ssl=1)
Posted inAstrochemistry
High Water D/H Ratio of the Interstellar object 3I/ATLAS is Consistent With a Low-metallicity Origin
[astro-ph.EP] Recent JWST observations have revealed unusually high 12C/13C ratios in carbon-bearing molecules of the interstellar object 3I/ATLAS, consistent with formation in a lower-metallicity environment than the present-day local interstellar […]
Posted inUncategorized
Multi-Wavelength Post-Perihelion Polarimetry of Interstellar Comet 3I/ATLAS
[astro-ph.EP] We present new post-perihelion polarimetric observations of the third discovered interstellar object, 3I/ATLAS (C/2025 N1; hereafter 3I), obtained using FORS2 at the Very Large Telescope, ALFOSC at the Nordic […]
![Example of the stacking procedure for the Maidanak data obtained on 2025 August 15, based on ten 60 s exposures in each of the B, V , and R filters. Left: Comet-centered stack, showing the coma morphology without trailing of the comet signal. The pink circle indicates an aperture radius of 10 000 km. Right: Sidereal stack used for photometric calibration, in which the comet appears trailed.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/The-Inbound.png?resize=1200%2C720&ssl=1)
Posted inComets and Asteroids
The Inbound Gas and Dust Evolution of Interstellar Comet 3I/ATLAS from Optical Spectroscopy and Multi-band Photometry
[astro-ph.EP] Interstellar objects (ISOs) provide direct constraints on the composition and evolution of extrasolar planetary systems. As the third confirmed ISO, comet 3I/ATLAS offers a rare opportunity to study pristine […]
Posted inComets and Asteroids
An Enriched Methane D/H Ratio in the Interstellar Object 3I/ATLAS
[astro-ph.EP]. Interstellar objects are interlopers from other planetary systems, and their volatile compositions provide a glimpse into planet formation around their host star.
![Candidate component r55 with period of P0 = 18.87 s in 1050–1140 MHz (a) and r952 with period of P0 = 16.58 s 1300–1450 MHz (b) in our search. The layout of the two panels are the same as Figure 1. -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/07/Periodic-Radio.png?resize=1200%2C720&ssl=1)
Posted inSETI & Technosignatures
Periodic Radio Technosignature Search Toward 3I/ATLAS With FAST
[astro-ph.IM] 3I/ATLAS, the third confirmed interstellar object discovered in the Solar System, provides a unique opportunity for targeted technosignature searches.
Posted inComets and Asteroids
Older Than The Sun: Astronomers Find New Clues To The Origin Of Interstellar Comet 3I/ATLAS
[ESO] Astronomers have used the European Southern Observatory’s Very Large Telescope (ESO’s VLT) to study the composition of 3I/ATLAS, the brightest interstellar object ever seen, in detail.
Posted inSETI & Technosignatures
Narrowband Radio Technosignature Search Toward 3I/ATLAS with FAST
[astro-ph.IM] 3I/ATLAS is the third confirmed interstellar object passing through the Solar System.
Posted inComets and Asteroids
The Dust Mineralogy of Interstellar Comet 3I/ATLAS from JWST/MIRI Observations
[astro-ph.EP] We present the first spectroscopic mineralogical analysis of the dust coma of an interstellar object (ISO) from JWST mid-infrared spectroscopy of 3I/ATLAS (3I).