terrestrial exoplanet Archives

Synthetic parameter-space projection of the Geochemical Metabolic Potential. Each small point is one of 𝑀sim=5000 nondimensional synthetic environments sampled over the five PGM components. Color indicates ΦPGM. Large diamond markers are synthetic heuristic anchors listed in Table 11; their positions are not empirical estimates, mission priorities, or cross-body rankings. The figure shows that high geochemical organization and high preservation-cycling support are separable: an environment can be energetic and catalytic but weakly archived, or strongly archived but less clearly powered. The labels designate conceptual regimes rather than fixed decision boundaries or mission priorities. -- Life (Basel)

Proto-Biosignatures and Planetary Geochemical Metabolism: A Thermodynamic Screening Model of Prebiotic Geochemical Organization

by Keith CowingAugust 31, 2026August 31, 2026

[Life (Basel)] Astrobiological observations usually return atmospheric, mineralogical, molecular, isotopic, or textural states rather than organisms.

Atmospheric gas volume mixing ratios (VMR), UV-NIR reflectance spectra, and NIR transit transmission spectra of our Archean Earth analogue

Biosignatures & Paleobiology

The Effects of M Star Age Dependent Ultraviolet Emission on Detecting and Interpreting Exoplanet Biosignatures

by Keith CowingAugust 24, 2026August 24, 2026

[astro-ph.EP] Given their abundance and observational advantages, M stars will arguably be the best candidates for characterizing and searching for biosignatures on terrestrial exoplanets in the near future.

An example of synthetic HWO Earth spectra at 10 pc generated with pyEDITH (upper) and the corresponding S/N values for each wavelength bin (lower).

Astronomy & Telescopes

The Exozodi Spectral Effect: Residual Habitable Zone Dust May Bias ExoEarth Characterization

by Keith CowingJuly 18, 2026July 18, 2026

[astro-ph.EP] All exoplanetary systems are expected to host exozodiacal dust, or exozodi, originating from planetesimals. For many stars, exozodi will likely be the largest source of astrophysical noise in direct […]

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

Exploring Exoplanets with Interferometry

by Keith CowingJune 11, 2026June 11, 2026

(Extract from the Executive Summary) Humanity stands at the threshold of answering one of its most profound questions: Does life exist beyond Earth?

Transmission spectrum of GJ 1214b using the 5% CH4-derived haze sample atmospheric composition. The sample from K84, G18/C23 C/O = 1 sample, and H24’s sample at 300 K are overplotted for reference. We include the observations from L. Kreidberg et al. (2014); E. M. R. Kempton et al. (2023b); E. Schlawin et al. (2024) with offsets for comparisons between models. The error bars account for 1σ uncertainties in the observations. Top: Spectra from 0.5 to 8 µm, where there are large differences in the resulting transmission spectrum between the sample and previous literature optical constants. Our samples pre- and post-irradiation produce largely flat spectra. Bottom: Spectra from 2 to 3 µm. We see slight changes between our preand post-irradiation transmission spectra, where our hazes are letting gaseous CO2 found in the simulated atmosphere to be more or less visible. -- astro-ph.EP

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

Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes

by Keith CowingJune 8, 2026June 8, 2026

Temperate sub-Neptune and terrestrial exoplanets could contain large inventories of water in various phases, such as water-dominated atmospheres or even oceans. Observations have shown that many exoplanets, including water worlds, […]

Radial velocity data for GJ 3378. Top: the combined RV time series. The orbit model is shown as a dashed line. Middle: RV residuals to a 1-planet model. Bottom: RVs phase-folded to the period of the exoplanet. Phase-binned RVs are shown as squares. -- astro-ph.EP

Astronomy & Telescopes, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release

A Revised Mass and Period for the Habitable Zone super-Earth GJ 3378b: A Planet Straddling the Cosmic Shoreline

by Keith CowingMay 19, 2026May 19, 2026

The nearby (d=7.7 pc) M4V star GJ~3378 is a target of our radial velocity (RV) exoplanet survey of fully convective stars in the Solar neighborhood with the near-infrared spectrograph HPF […]

Thermal evolution of a 1 M⊕ model with no atmosphere (top row) and a model with a thin 0.01% H-He by mass atmosphere/envelope.

Astrochemistry, Astrogeology, Desert Worlds, Exoplanets, -moons, -comets, Gas Giants, Ice Giant, Icy Worlds, Status Report, Water/Hycean Worlds & Oceanography

ORCHARD: A General Planetary Evolution Code

by Keith CowingApril 30, 2026April 30, 2026

We present ORCHARD, a publicly available planetary evolution code based on the gas giant evolution code, APPLE, capable of modeling the evolution and structures of terrestrial, super-Earth, sub-Neptune, Neptune, and […]

Molecular composition of haze samples from the N2-rich/CH4 and H2O-rich/CH4 experiments. Left panels: Very high-resolution mass spectra (m/z 150–800) of haze particles produced from the N2-rich/CH4 and H2O-rich/CH4 experiments, acquired in both positive and negative ionization modes. Assigned CHO, CHN, and CHON species are shown in red, green, and yellow, respectively, while grey data points correspond to mass peaks with no formula matched within the mass accuracy threshold (< 0.0001 Da). For each spectrum, the adjacent pie charts summarize the percentage of molecular formulas and their relative abundances based on summed peak intensities of the assigned organic species. Right panels: Corresponding van Krevelen diagrams combining matched formulas from both ionization modes, shown as H/C vs. N/C and H/C vs. O/C. Each circle represents an assigned formula, where color denotes the degree of unsaturation and marker size scales with peak intensity. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report

Influence Of CO Versus CH4 On Organic Haze Formation In Atmospheres Of Diverse Terrestrial Exoplanets

by Keith CowingApril 7, 2026April 7, 2026

Context. Terrestrial exoplanets are expected to host secondary, high-metallicity atmospheres derived from outgassing of volatiles such as N2, CO2, H2O, CH4, and CO. Photochemical organic hazes are likely to form […]

Contributions to the peak 𝑃𝑅 from the bow shock and magnetopause at 𝜂 = 5.38018 × 108cm2s−1 for Case #1 (panel a), Case #2 (top of panel b), and Case #3 (bottom of panel b). The volumetric renderings show ∇ · Stotal in erg cm−3 s−1. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Space Weather & Heliophysics, TRAPPIST-1

Resistive MHD Simulations of Stellar Wind-Magnetosphere Coupling in TRAPPIST-1e

by Keith CowingApril 2, 2026April 2, 2026

Close-in terrestrial exoplanets around M dwarfs reside in dense, magnetized winds, where non-ideal plasma coupling can strongly affect how electromagnetic energy is redistributed within the dayside interaction region.

Height scales of atmospheres of Solar System’s terrestrial planets. The solid lines show the temperature profiles against altitude, while the background color reflects the atmospheric pressure. Horizontal dashed lines denote the average positions of atmospheric boundaries: tropopause ("t"), stratopause ("s"), and mesopause ("m"). Vertical cyan lines depict the extension of ionospheres ("i") under typical conditions. The "⊙" symbol denotes the 100 mbar level. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Magnetic Fields, Electromagnetism, bioelectricity,, Status Report

Upper Atmosphere Dynamics And Drivers Of Volatiles Loss From Terrestrial-type (exo)Planets

by Keith CowingFebruary 18, 2026February 18, 2026

Volatile loss from exoplanetary atmospheres and its possible implications for the longevity of habitable surface conditions is a topic of vigorous debate currently.

terrestrial exoplanet

Proto-Biosignatures and Planetary Geochemical Metabolism: A Thermodynamic Screening Model of Prebiotic Geochemical Organization

The Effects of M Star Age Dependent Ultraviolet Emission on Detecting and Interpreting Exoplanet Biosignatures

The Exozodi Spectral Effect: Residual Habitable Zone Dust May Bias ExoEarth Characterization

Exploring Exoplanets with Interferometry

Ultraviolet Radiation Effects on the Optical Properties of Water-Dominated Exoplanet Hazes

A Revised Mass and Period for the Habitable Zone super-Earth GJ 3378b: A Planet Straddling the Cosmic Shoreline

ORCHARD: A General Planetary Evolution Code

Influence Of CO Versus CH4 On Organic Haze Formation In Atmospheres Of Diverse Terrestrial Exoplanets

Resistive MHD Simulations of Stellar Wind-Magnetosphere Coupling in TRAPPIST-1e

Upper Atmosphere Dynamics And Drivers Of Volatiles Loss From Terrestrial-type (exo)Planets

How A Deep-sea Protein Adapts To An Extreme Environment

Fingerprints Inside Our Sun Could Reveal If It Once Swallowed A Planet

Climates Of Gl 514 b

Cosmic Radiation at Flight Altitudes Rises When the Sun Is Less Active

The History Of Enzyme Evolution Embedded In Metabolism