terrestrial exoplanet Archives

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.

Schematic of episodic atmospheric collapse and regeneration through impacts for a tidally locked planet. A) The planet has a volatile rich atmosphere which redistributes heat from the day- to the nightside. B) Atmospheric escape thins the atmosphere, heat redistribution becomes less efficient, nightside temperatures drop. C) Nightside temperatures have reached the volatile condensation temperature, the atmosphere collapses. D) Volatiles outgassed through volcanism or magma ocean pockets accumulate on the nightside as ice. E) An impactor hits the nightside and vaporises ice and rock. Hot vapour, ejecta, and silicate rain further vaporise the nightside ice sheets (see Section 2.2 for details). An atmosphere is regenerated. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Extinction events, Impact events, Status Report

Atmospheric Collapse And re-inflation Through Impacts For Terrestrial Planets Around M Dwarfs

by Keith CowingOctober 31, 2025October 31, 2025

Detection of an atmosphere around a terrestrial exoplanet will be a major milestone in the field, but our observational capacities are biased towards to tidally locked, close-in planets orbiting M-dwarf […]

Range of best-fit phase curve and eclipse models for TRAPPIST-1 b and c. The detrended data are shown with gray dots and binned data with black dots. Red curves show the light curve model for each JWST program that observed TRAPPIST-1 b and c at 15µm using MIRI F1500W; the shading spans the range of models drawn from the posterior distribution of the day flux, night flux and phase offset for planets b and c from Analysis # 1 at 2-σ. The top panel shows the phase curve from GO 3077; the second row displays the five visits from GO 1177 (PI: Greene); and the third row presents the four visits from GO 2304 (PI: Kreidberg), along with a zoom-in on the double occultation observed in GO 3077. The expected transit and eclipse timings for each planet from [19] are shown in vertical dashed and plain lines respectively (purple for b, orange for c, and green for g). -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

First JWST Thermal Phase Curves Of Temperate Terrestrial Exoplanets Reveal No Thick Atmosphere Around TRAPPIST-1 b and c

by Keith CowingSeptember 3, 2025September 3, 2025

We report JWST/MIRI 15 μm phase curves of TRAPPIST-1 b and c, revealing thermal emission consistent with their irradiation levels, assuming no efficient heat redistribution.

The phase curve of a planet over one rotation at eight different illumination phases. The images at the right show renderings of the planet’s illuminated surface throughout the observation. Each curve represents a different viewing geometry, the observer-planet-star angle, with the corresponding planetary illumination phase shown by the colored circles in the legend. The top (blue) curve shows a fully illuminated planet, while the lower curves show various partial illumination scenarios down to a completely dark planet (purple). The gray curve represents the classical edge-on viewing case exhibiting the full range of phase variations. -- astro-ph.SR

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Ice Giant, Icy Worlds, Imaging & Spectroscopy, Status Report

Requirements For Joint Orbital Characterization of Cold Giants and Habitable Worlds with Habitable Worlds Observatory

by Keith CowingJuly 30, 2025July 30, 2025

We determine optimal requirements for the joint detection of habitable-zone planets and cold giant planets with the Habitable Worlds Observatory (HWO).

terrestrial exoplanet

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

Atmospheric Collapse And re-inflation Through Impacts For Terrestrial Planets Around M Dwarfs

First JWST Thermal Phase Curves Of Temperate Terrestrial Exoplanets Reveal No Thick Atmosphere Around TRAPPIST-1 b and c

Requirements For Joint Orbital Characterization of Cold Giants and Habitable Worlds with Habitable Worlds Observatory

White Paper On Phototrophic Biosignatures: Research Priorities For The Search For Life On Other Worlds

Autonomous AI-Cosmoindustry and the Quiet Expansion Filter: A Threshold-Based Resolution of the Fermi Paradox

A Scalable Path to Astrometric Exomoon Discoveries with the Nautilus Space Observatory

20 Years Later: The ALH 84001 Debate in Context with Viking’s Results. Lessons Learned and Portals Opened

Ocean Planet Research: 31 New Species Discovered in Two Weeks of Deep Sea Exploration