astro-ph.EP Archives

A summary of the CO and N2 reported in various comets with respect to parent molecule (top) and with respect to water (bottom).

Analog Studies, Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Status Report

CO and N2 Produced from H2O, CO2, and NH3 Cometary Ice Analogs

by Keith CowingApril 6, 2026April 6, 2026

Hypervolatile species such as carbon monoxide (CO) and molecular nitrogen (N2) have been detected in comets, and could be used to constrain comet formation temperature conditions if their presence is […]

Period-radius plot for planets in single-star (gray points) and binary-star (colored points) systems considered in this work. Colors correspond to log10(ρ), i.e. the projected physical binary separation in au. We restricted the sample to planets with 1 < P < 100 d and 0.5 < Rp < 4R⊕. The planets in binary-star systems have a similar distribution in period-radius space as the planets in single-star systems, although the relative occurrence rate of sub-Neptunes (2 < Rp < 4R⊕) is suppressed in small-separation binary-star systems (K. Sullivan et al. 2024). -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report, Stellar Cartography

Planetary Architectures of Kepler Compact Multis with Binary Star Companions

by Keith CowingApril 6, 2026April 6, 2026

Planets in binary-star systems exhibit demographic differences compared to planets in single-star systems.

Dynamical evolution of planetary embryos in a representative simulation of Scenario FIX. Each line corresponds to one embryo: gray lines show all embryos, while colored lines highlight those that survive until the end of the integration at ∼ 50 Myr. Panels display the semi-major axis (top left), eccentricity (top right), inclination (bottom left), and planetary mass (bottom right). The horizontal dashed blue line in the semi-major-axis panel marks the fixed inner disk edge at 0.01 au, which is applied only during the gas-disk phase (up to 10 Myr). -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Status Report, Stellar Cartography

The Role Of Inner Disk Edges In Shaping Ultra-short-period Planet Systems Around Late M Dwarfs

by Keith CowingApril 5, 2026April 5, 2026

Close-in rocky planets are the most common type of exoplanets around late M dwarfs, ranging from more temperate worlds to highly irradiated lava planets with molten surfaces, and many theoretical […]

Summary of our method and comparison to the traditional grid modeling approach. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report, Water/Hycean Worlds & Oceanography

Unusually Hot Interiors Could Reconcile the Missing Methane Problem for Warm-to-Hot Exoplanets with Hydrogen Atmospheres

by Keith CowingApril 4, 2026April 4, 2026

JWST is revolutionizing the field of exoplanet atmospheres by delivering unprecedented spectroscopic constraints on their chemical compositions. It has provided tight constraints on the abundances of dominant carbon- and oxygen-bearing […]

Visualization of the HAT-P-12b transmission spectrum and the underlying opacity contributions. Top: Combined spectra from the three JWST instruments and HST STIS (Alexoudi et al. 2020) with 1σ uncertainties, together with the best-fit model with its 3σ credible interval.Model spectra including only the opacity of individual contributors (chemical species or non-gray cloud parametrization) are also shown. Bottom: Absorption cross sections σ of all tested chemical species; significantly detected species are emphasized with thicker lines. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Information Content Of JWST Transmission Spectroscopy Of The Exoplanet HAT-P-12b From The Optical To The Mid-infrared

by Keith CowingApril 4, 2026April 4, 2026

Marginal posterior distributions of the chemical abundances for all included molecules, retrieved using different JWST instrument combinations. The shown distributions were derived from the samples via kernel density estimation (KDE; […]

MIRI F1500W light curves of GJ 3473 b at secondary eclipse. The raw and binned data are shown in light grey and purple, respectively. The pink curves correspond to the median model predictions from the joint fit, while the brown data points depict the binned model. The model shown here corresponds to the G. Tovar Mendoza et al. (2022) flare model case, as described in Appendix C, used to model the flare-like feature during the second visit. The dotted vertical lines show the nominally masked region in the second visit. Compared to Figure 2, this figure displays the data without correcting for systematics. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Hot Rocks Survey V: Secondary Eclipse Photometry of GJ 3473 b with JWST/MIRI

by Keith CowingApril 3, 2026April 3, 2026

JWST is transforming our ability to characterise small exoplanets, from sub-Neptunes to rocky worlds. A key open question is whether highly irradiated rocky planets can retain atmospheres or are stripped […]

Dust surface density evolution in the fiducial model without disk buildup (left) and with disk buildup taken into account (right). Time zero refers to the moment the gas disk reaches maximum mass in the model including its buildup, corresponding to the time the dust is initialized in the model without disk buildup. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Icy Worlds, Imaging & Spectroscopy, Status Report

Dust Evolution During Protoplanetary Disk Bbuildup Enhances CO Ice Relative To Water

by Keith CowingApril 1, 2026April 1, 2026

Water ice is expected to be the dominant volatile component of bodies formed in the outer Solar System. However, recent observations of comets and trans-Neptunian objects suggest that the relative […]

Synthetic exoplanet population, colour coded by number of planets per bin in logarithmic semi-major axis and planet mass space, using the nominal model for a sample of Nstar=5000 different mass stars

Astrochemistry, Astrogeology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

A Break In Planet Occurrence Near The Pebble Isolation Mass Should Be Observable By The Roman Microlensing Survey

by Keith CowingApril 1, 2026June 10, 2026

Microlensing detections are uniquely well-suited to probing the population of planets outside the water iceline, down to planetary masses comparable to the Earth.

RV residuals of LHS 3844 after subtracting the per-instrument offsets and the orbital component, sampled from the posterior distribution of the model with highest marginal likelihood: WN+SE+QP kernel without drift terms (d0). The blue curve represents the median of the Gaussian Process (GP) predictive distribution, computed over the full posterior of the GP hyperparameters and marginalized over the linear parameters and orbital period. The shaded region denotes the 68% confidence interval. Data points correspond to ESPRESSO observations taken before (green circles) and after (red squares) the instrumental upgrade. Error bars include both the reported measurement uncertainties and the empirically derived per-instrument jitter, added in quadrature. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Icy Worlds, Status Report

Weighing The Mass Of LHS 3844 b

by Keith CowingApril 1, 2026April 1, 2026

Context: LHS 3844 b (TOI-136 b) is a ultra short-period, Earth-size exoplanet detected by TESS. It is one of the most favourable object for atmospheric characterisation and the study of […]

Schema of internal workings of the agent object. The agent comprises the LLM, the tools and the context. Figure adapted from Roman & Roman (2026). -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Agentic Science Toolkit for Exoplanet Research

by Keith CowingApril 1, 2026April 1, 2026

The expansion of exoplanet observations has created a need for flexible, accessible, and user-friendly workflows.

astro-ph.EP

CO and N2 Produced from H2O, CO2, and NH3 Cometary Ice Analogs

Planetary Architectures of Kepler Compact Multis with Binary Star Companions

The Role Of Inner Disk Edges In Shaping Ultra-short-period Planet Systems Around Late M Dwarfs

Unusually Hot Interiors Could Reconcile the Missing Methane Problem for Warm-to-Hot Exoplanets with Hydrogen Atmospheres

Information Content Of JWST Transmission Spectroscopy Of The Exoplanet HAT-P-12b From The Optical To The Mid-infrared

Hot Rocks Survey V: Secondary Eclipse Photometry of GJ 3473 b with JWST/MIRI

Dust Evolution During Protoplanetary Disk Bbuildup Enhances CO Ice Relative To Water

A Break In Planet Occurrence Near The Pebble Isolation Mass Should Be Observable By The Roman Microlensing Survey

Weighing The Mass Of LHS 3844 b

Agentic Science Toolkit for Exoplanet Research

Direct Dating Of 3.5 Ga Biogenic Carbon In A Microbial Mat Remnant, Singhbhum Craton, India

The VLA and High-Frequency SETI: Expanding The Search for Life

GEMS JWST: HATS(-6 b): A Sub-solar Metallicity Giant Planet With Water, Methane And Ammonia In Its Atmosphere

The Tidal Venus Phenomenon: Demographics and Case Studies

RNA Droplets May Have Helped Start life on Earth