![LDPI–ReTOF mass spectrum obtained after the deposition of 40 ML pure NH3 ice at 15 K (red), without VUV irradiation. A reference mass spectrum obtained for a bare, clean substrate is presented for comparison (black). The spectra are offset for clarity -- [astro-ph.IM]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Quantifying.png?resize=1200%2C720&ssl=1)
[astro-ph.IM] Gas–grain astrochemical models predict that a substantial fraction of elemental nitrogen in dense cores and protoplanetary disks is locked in molecular nitrogen (N2), in the gas or ice phase, […]
Comet
Posted inAstrochemistry
JWST Reveals Refractory-Rich Water Ice in Interstellar Comet 3I/ATLAS: Evidence for a Continuum of Grain Properties across Protoplanetary Disks
[astro-ph.EP] We present JWST/NIRSpec PRISM observations of the interstellar comet 3I/ATLAS obtained on 2025 August 6 (Epoch 1), 2025 December 22 (Epoch 2), and 2026 April 1 (Epoch 3), spanning […]
Posted inComets and Asteroids
Fragmentation Dynamics of Pristine Interstellar Comets: An Exploratory Multi-Physics Simulation Study
[astro-ph.EP] We present an exploratory numerical model for the thermal evolution and fragmentation of pristine interstellar comets during a first passage through the inner Solar System, and we apply it […]
![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 inAstrogeology
Trans-Neptunian Objects Remember Their Past
[NASA]. For the first time, scientists used the joint power of NASA’s Hubble and James Webb Space Telescopes to study some of the most far-flung bodies in our solar system, […]
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 […]
![LT solution with 2036 launch. Continuous thick curve: trajectory, Short segments: thrust law, Dashed lines: planet and comet orbits. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/09/Double-Gravity.png?resize=1200%2C718&ssl=1)
Posted inComets and Asteroids
Double Gravity-Assist Rendezvous Trajectory to Halley’s Comet Using Deep-Space Low Thrust
[astro-ph.EP] The perihelion of comet 1P/Halley in 2061 is an excellent chance to revisit this object of outstanding scientific and cultural relevance. During its 1986 approach to the Sun, it […]
Posted inExoplanets, -moons, -comets
Comets May Have Transported Water To A Young Planetary System
[Lund University] Astronomers at Lund University in Sweden have found evidence of exocomets – comets in other solar systems – orbiting a young star similar to our Sun. The observations […]
![Occam’s razor-based deconvolution result of the subset of signals associated with CnHmN parent and fragment species detected by the DFMS on 3 August 2015. The measured signals (measured) are given in arbitrary units (a. u.) with 30 % error margins. The different contributions of the chosen candidate molecules are colour-coded according to their molecular structure – in shades of red and purple for chain-based molecules and in shades of green and blue for cyclic molecules. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Nitrogen.png?resize=1200%2C707&ssl=1)
Posted inComets and Asteroids
Nitrogen- And Nitrogen-oxygen-bearing Organic Molecules In Comet 67P/Churyumov-Gerasimenko: An Untargeted Investigation
[astro-ph.EP] Comets provide a unique window into the history of the Solar System as they carry some of the best-preserved material and make it available to in situ exploration.
![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 […]