Related papers: Dynamical simulation of the Interstellar Comet 3I/…
We aim to characterize the physical and activity properties of the interstellar comet 3I/ATLAS through spectroscopic and photometric observations during the first month after its discovery. We performed time-series photometry and long-slit…
Interstellar comet 3I/ATLAS (C/2025 N1) exhibits an unusual, tightly collimated dust feature in the sunward hemisphere which has been widely described as an anti-tail. At the same time, precise constraints on the nucleus size have been…
Interstellar comets provide rare opportunities for probing the diversity of refractory and volatile inventory around other stars. As the second ever interstellar comet, and the third interstellar object, 3I/ATLAS has been the focus of…
We present multi-epoch optical spectroscopy of the interstellar comet 3I/ATLAS obtained between December 2025 and January 2026 (heliocentric distances 1.8-3.3 au), yielding post-perihelion production rates and mixing ratios for CN, C$_3$,…
The interstellar object 3I/ATLAS shows a weak cometary activity. Its brightness suggests a maximum radius of ~10km (A/0.05)^{-1/2} for an asteroid with an albedo A. I show that interstellar objects with that radius would amount to an…
Interstellar objects are the ejected building blocks of other solar systems. As such, they enable the acquisition of otherwise inaccessible information about nascent extrasolar systems. The discovery of the third interstellar object,…
We present a detailed analysis of the trajectory of the interstellar comet 3I/ATLAS, focusing on its non-gravitational acceleration (NGA) parameters and their uncertainties. Orbital solutions are computed with models that implement…
Comets are primitive remnants of the early Solar System whose composition offers fundamental clues to their formation and evolution. High-resolution, broad-wavelength spectroscopy is crucial for identifying volatile species and constraining…
Interstellar objects (ISOs), particularly those with cometary activity, provide unique insight into the primordial physical and chemical conditions present during the formation of the planetary system in which they originated. Observations…
The Earth will pass approximately downstream of the previous position of comet C/2023 A3 (Tsuchinshan-ATLAS) during 2024 October 10-13. We predict that spacecraft at the Sun-Earth Lagrange Point 1, L1, have a significant likelihood to…
Interstellar objects (ISOs) provide unique insights into the building blocks and conditions of extrasolar planetary systems. The newly discovered object, 3I/ATLAS (C/2025 N1), represents the third known ISO after 1I/'Oumuamua and…
Cometary activity from interstellar objects provides a unique window into the environs of other stellar systems. We report blue-sensitive integral field unit spectroscopy of the interstellar object 3I/ATLAS from the Keck-II-mounted Keck…
We identified a new ultra-distant comet C/2019 E3 (ATLAS) exhibiting preperihelion cometary activity at heliocentric distances $\gtrsim\!20$ au, making it the fourth member of this population after C/2010 U3 (Boattini), C/2014 UN$_{271}$…
3I/ATLAS is the third confirmed interstellar object to visit our Solar System, and only the second to display a clear coma. Infrared spectroscopy with the James Webb Space Telescope (JWST) provides the opportunity to measure its coma…
3I/ATLAS is the third known interstellar object to pass through our Solar System. NASA's Transiting Exoplanet Survey Satellite (TESS) made dedicated observations of 3I/ATLAS between 15 -- 22 January 2026 (Sector 1751), capturing…
3I/ATLAS is an interstellar object whose activity provides critical insights into its composition and origin. However, due to its orbital geometry, the object is too close to the Sun near perihelion to be observed from the ground, and…
We point out that on 22 January 2026, the interstellar object 3I/ATLAS will align to within an exceptionally small angle, alpha= 0.69 degrees, with the Earth-Sun axis. This rare alignment provides unique circumstances for measuring the…
We utilize serendipitous observations from the Asteroid Terrestrial-impact Last Alert System (ATLAS) and the Zwicky Transient Facility (ZTF) in addition to targeted follow-up observations from the Las Cumbres Observatory (LCO) and Liverpool…
We present the first spectroscopic characterization of an interstellar object at mid-infrared wavelengths. Post-perihelion observations of 3I/ATLAS using the JWST/MIRI medium-resolution spectrometer were obtained on 2025 December 15--16 and…
The discovery of the third interstellar object (ISO), 3I/ATLAS (`3I'), provides a rare chance to directly observe a small body from another Solar System. Studying its chemistry and dynamics will add to our understanding of how the processes…