[UC Riverside] The Planetary Geochemistry and Astrobiology Laboratory is led by Assistant Professor Fabian Klenner, a new faculty member in UCR’s Department of Earth and Planetary Sciences. His research focuses […]
astrochemistry
![Upper Panels. Maps of N × ρ for ortho-H2O and para-H2O, the derived OPR, and Trot(H2O) for the 6 µm band measured on February 28. Note that N for each species has been corrected for the derived OPR. Lower Panels. As in the upper panels for the 2.6 µm H2O bands measured on March 1. -- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/JWST-Spatial.png?resize=1200%2C727&ssl=1)
Posted inComets and Asteroids
JWST Spatial-Spectral Mapping of Green Comet C/2022 E3 (ZTF)
[astro-ph.EP] We report a survey of molecular emission from cometary volatiles using the James Webb Space Telescope (JWST) toward Oort cloud comet C/2022 E3 (ZTF) carried out on UT 2023 […]
![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 […]
![Schematic of generative process to determine most chemically relevant molecular candidates for the unassigned spectroscopic transitions.-- [astro-ph.GA]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Automated.png?resize=1200%2C711&ssl=1)
Posted inAstrochemistry
Automated Assignment and Prediction of Molecules in Astronomical Line Surveys Using Machine-Learning-Based Chemical Embeddings
[astro-ph.GA] Modern radio telescopes generate vast amounts of observational data, offering valuable insights into the molecular composition of interstellar sources. Identifying the molecules within these datasets typically involves time-consuming and […]
![Mechanisms that contribute to dust growth just beyond the snow line. Many-seed icy aggregates grow in the outer disk’s regions due to the high sticking efficiency of water ice and disintegrate as they cross the water snow line (green-to-blue interface) into silicate monomers and water vapor. Both diffuse back across the snow line due to turbulence, facilitating further accumulation of icy water and the growth of icy aggregates just behind the snow line, effects found in our numerical model as well (see Figs. 7 and E.2).-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Hydrodynamics.png?resize=1200%2C721&ssl=1)
Posted inAstrogeology
Hydrodynamics Modeling Of The Water Snow Line In Young Protoplanetary Disks With Dust-size-dependent Opacities
[astro-ph.EP] Aims. We investigated the properties of the water snow line during the early stages of disk evolution, paying particular attention to the effects of gravitational instability and dust growth […]
Posted inAstrochemistry
Catalytic Formation of H2 On Carbonaceous Dust Grains – Implications For Interstellar Observations
[astro-ph.GA] We use kinetic Monte Carlo (KMC) simulations to study molecular hydrogen formation on carbonaceous dust grain surfaces, validated against recent laboratory measurements of H2 formation on coronene films at […]
Posted inStellar Cartography
A High-Resolution Spectroscopic Survey of Directly Imaged Companion Hosts: III. Characterization of the Cold Imaged Planet Hosts AF Lep A and ε Indi A
[astro-ph.EP] JWST has enabled the measurement of carbon, oxygen, and sulfur abundances in the atmospheres of directly imaged planets. Interpretation of these abundances from a planet formation standpoint requires the […]
![CI mass as a function of radial distance from the host star, for a continuum of solid surface densities. Over-plotted is the FI1 mass (𝑀¤ = 10−9 M⊙ yr−1 ) for a continuum of maximum Stokes numbers, as well as the MFI1 (opaque purple) and MFI2 (dashed red) masses and the PI mass (dotted black). The last three show no continuum of mass distributions, since we vary their initial mutual Hill spacing within the simulation. Thus, all initial simulations begin from the same mass distribution model, albeit with a different number of embryos at different spacings.-- [astro-ph.EP]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/Effects-of-Pebble.png?resize=1200%2C715&ssl=1)
Posted inExoplanets, -moons, -comets
Effects Of Pebble Accretion Isolation Mass On Observable Exoplanet Properties
[astro-ph.EP] The Kepler Mission has discovered a plethora of planetary systems with super-Earth sized planets.
![The top panel shows comparisons of the observed spectrum of JADES-GS-BD-11 (black with grey 1σ error bars) and the median retrieved spectrum for both the PH3 and non-PH3 petitRADTRANS (red and green, respectively, with 1σ central credible intervals shaded around the median). The bottom panel shows the difference between the retrieved and observed spectra, divided by the observed uncertainty. The two retrieved median spectra are generally within 1σ of each other everywhere except at 4.3 µm (the Q-branch of the PH3 feature).-- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/08/JWSTNIRSpec.png?resize=1200%2C717&ssl=1)
Posted inBrown Dwarfs
JWST/NIRSpec Spectra for Three Ultracool Brown Dwarfs Detected in Extragalactic Surveys: Further Evidence for Phosphine Absorption
[astro-ph.SR] We present JWST NIRSpec prism spectra for three ultracool brown dwarfs discovered in extragalactic survey data, two from the JWST Advanced Deep Extragalactic Survey (JADES), and one from Public […]
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.