TRAPPIST-1 Archives

Eccentricity evolution of the four planets in the TOI-700 system over 10,000 years of the integration after 100 Myr of evolution. This plot is a zoom-in of a small range of bottom panel of Figure 2.. Additionally, all planets have low but non-zero eccentricity 0.03 < e < 0.1 over their entire evolution. -- astro-ph.EP

Dynamical Interactions and Habitability in the TOI-700 Multi-Planet System

by Keith CowingFebruary 3, 2026February 3, 2026

The discovery of a second earth sized planet (TOI-700e) interior to the habitable candidate TOI-700d has prompted further research into this system, as the additional planet makes the TOI-700 system […]

Stellar irradiation received at the top of the atmosphere on Earth 2.7Ga ago (blue)30 and on TRAPPIST-1e (orange)29. Cross section per molecules of O2, O3 and H2O2 are represented in grey. Knowing O3 less abundant than O2, their photolysis shifting point is around 200nm, close to where the flux balance change between the Sun and TRAPPIST-1. -- astro-ph.EP

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Possible Favored Great Oxidation Event Scenario On Exoplanets Around M-Stars With The Example Of TRAPPIST-1e

by Keith CowingJanuary 27, 2026June 10, 2026

The Great Oxidation Event (GOE), which marked the transition from an anoxic to an oxygenated atmosphere, occurred 2.4 billion years ago on Earth, several hundreds of millions of years after […]

Spectra of different stellar types. On the left, scaled and vertically shifted flux from NewEra stellar grid is shown on the y-axis and wavelength is shown in microns on the x-axis. On the right, the corresponding pressure-vs-temperature profiles are shown, with temperature in Kelvin on the x-axis and pressure in bars on the y-axis. Prominent atomic and molecular features are annotated (Cushing et al. 2005; Rajpurohit et al. 2018, and references therein). Molecular features increase as we move toward cooler stars. In particular, the FeH and water features (shaded blue bands) stand out in the M8 model and are not present in hotter stars. -- astro-ph.SR

Astronomy & Telescopes, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report, TRAPPIST-1

Overestimated Pressure Broadening Misleads Model Spectra in Cool M Dwarf Stars

by Keith CowingJanuary 25, 2026January 25, 2026

Available one-dimensional stellar models fail to reproduce the observed spectrum of the ultracool M dwarf TRAPPIST-1.

TESS target pixel file image created with tpfplotter for TOI-6716 (left) and TOI-7384 (right) observed in Sector 88 (2025 Jan 14 – 2025 Feb 11) and Sector 87 (2024 Dec 18 – 2025 Jan 14) respectively. The target stars are indicated by a white cross, and the TESS aperture is represented by the red hatch. Red dots highlight GAIA-DR3 sources with varying sizes corresponding to their magnitude relative to the respective target stars. -- astro-ph.EP

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

Two Temperate Earth- and Neptune-sized Planets Orbiting Fully Convective M dwarfs

by Keith CowingJanuary 12, 2026January 12, 2026

As the diversity of exoplanets continues to grow, it is important to revisit assumptions about habitability and classical HZ definitions. In this work, we introduce an expanded ‘temperate’ zone, defined […]

C.1: Same as Figure 4 but for the tidal temperature. These values are compared with the equilibrium temperature of all planets (full black circles) and the brightness temperature of T-1b and c (full red circles) estimated in Ducrot et al. (2020). We also give the recently acquired brightness temperatures measured by the JWST: the temperature of planet b comes from Greene et al. (2023), and that of planet c from Zieba et al. (2023). -- astro-ph.EP

Astrogeology, Exoplanets, -moons, -comets, Habitable Zones, Press Release, TRAPPIST-1

Estimation Of The Tidal Heating In The TRAPPIST-1 Planets. Influence Of The Internal Structure

by Keith CowingJanuary 8, 2026January 8, 2026

With the arrival of JWST observations of the TRAPPIST-1 planets, it is timely to reassess the contribution of tidal heating to their heat budget. JWST thermal phase curves could reveal […]

The incident photon flux density for the modern-day Earth (black), Archean Earth at 2.65 Ga (blue), and TRAPPIST-1e (red). The spectral resolution has been reduced for clarity. The shaded regions represents three relevant bandpasses for photosynthesis: standard PAR (0.40-0.70 µm), extended PAR (0.40-0.75 µm), and anoxic PAR (0.40-1.1 µm). -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Origin & Evolution of Life, Radiation, Space Weather & Heliophysics, Status Report, Terraforming & Geoengineering, TRAPPIST-1

Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets

by Keith CowingJanuary 7, 2026January 7, 2026

The rise of oxygen in the Earth’s atmosphere during the Great Oxidation Event (GOE) occurred about 2.3 billion years ago. There is considerably greater uncertainty for the origin of oxygenic […]

Illustration of flare heating in three types of stars. The dashed line marks the stellar surface; blue areas show the quiet atmosphere, and red areas show regions heated during a white-light flare. Vertical arrows indicate the radiative output, with length proportional to intensity. In solar-like stars (left), heating is regulated by hydrogen ionization, which limits temperatures of white-light flares to ∼ 9000 K. In late M dwarfs like TRAPPIST-1 (middle), molecular hydrogen dissociation acts as a thermostat, capping temperatures of white-light flares near ∼ 3500 − 4000 K. In early M dwarfs (right), insufficient concentration of H2 means the dissociation thermostat is ineffective, allowing higher white-light flare temperatures. -- astro-ph.SR

Exoplanets, -moons, -comets, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Molecular Hydrogen Controls The Temperatures Of Flares On TRAPPIST-1

by Keith CowingJanuary 6, 2026January 6, 2026

Early JWST observations of TRAPPIST-1 have revealed an unexpected puzzle: energetic white-light flares (E>1030 erg) reach temperatures of only ∼3500–4000,K, nearly three times cooler than typical solar flares, which peak […]

Final semi-major axes of satellites versus their initial orbital distance (in Hill radii) for TRAPPIST-1 e. -- astro-ph.EP

Exoplanets, -moons, -comets, Status Report, TRAPPIST-1

Orbital Stability Of Moons Around The TRAPPIST-1 Planets

by Keith CowingDecember 23, 2025December 23, 2025

We investigate the dynamical stability of potential satellites orbiting the seven planets of the TRAPPIST-1 system using a suite of N-body simulations.

Top: White light curves of observation 1, observation 3, and observation 15 from the NA reduction, both at native time resolution in black and binned to 25x in red for visibility. All transits are labeled by planet. Observation 1 also has a large flare that occurs right before the egress of planet e. Shown in the upper right is a schematic of our proposed setup, with the true overlapping planetary transit chords taken from Agol et al. (2021). Middle: Hα light curve from the NA reduction. Peaks in Hα correspond to flaring events, many of which are not visible in the white light curve, at least without hints to their location from the Hα signature. Note that the light curves are binned in time to 50x (to approximately 70 second bins) relative to that shown in the white light curve for visibility in the low signal single wavelengths shown. Bottom: Transmission spectrum of TRAPPIST-1 e (top) and TRAPPIST-1 b (bottom) for observation 1, observation 3, and observation 15 from left to right. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1

JWST TRAPPIST-1 e/b Program: Motivation and First Observations

by Keith CowingDecember 9, 2025December 9, 2025

One of the forefront goals in the field of exoplanets is the detection of an atmosphere on a temperate terrestrial exoplanet, and among the best suited systems to do so […]

Located about 39 light-years from Earth, the TRAPPIST system resembles a miniature version of our solar system: The star, an ultracool red dwarf, and all its planets would comfortably fit inside the orbit of planet Mercury. Credit NASA, ESA, CSA, STScI, Joseph Olmsted (STScI)

Astrochemistry, Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, Titan, TRAPPIST-1

A New Look At TRAPPIST-1e, An Earth-sized, Habitable-zone Exoplanet

by Keith CowingDecember 5, 2025December 5, 2025

Of the seven Earth-sized worlds orbiting the red dwarf star TRAPPIST-1, one planet in particular has attracted the attention of scientists, because it orbits the star within the “Goldilocks zone” […]

TRAPPIST-1

Dynamical Interactions and Habitability in the TOI-700 Multi-Planet System

Possible Favored Great Oxidation Event Scenario On Exoplanets Around M-Stars With The Example Of TRAPPIST-1e

Overestimated Pressure Broadening Misleads Model Spectra in Cool M Dwarf Stars

Two Temperate Earth- and Neptune-sized Planets Orbiting Fully Convective M dwarfs

Estimation Of The Tidal Heating In The TRAPPIST-1 Planets. Influence Of The Internal Structure

Dearth of Photosynthetically Active Radiation Suggests No Complex Life on Late M-Star Exoplanets

Molecular Hydrogen Controls The Temperatures Of Flares On TRAPPIST-1

Orbital Stability Of Moons Around The TRAPPIST-1 Planets

JWST TRAPPIST-1 e/b Program: Motivation and First Observations

A New Look At TRAPPIST-1e, An Earth-sized, Habitable-zone Exoplanet

A Martian Horizon Last Monday Afternoon

Habitable-zone Earths At The Detection Frontier: Measured Completeness And False-alarm Rate Of A Transit Pipeline For The PLATO M-dwarf Sample

A Homogeneous Survey Of JWST MIRI Transmission Spectra Of 10 Exoplanets

Retrieving Ocean Glint Reflectance Signatures From Directly Imaged Earth-like Exoplanets

Analytical Platform (Microsampling, Catapulting, Trapping, and LIBS) for the Characterization of Discrete Domains in Samples of Astrochemical Interest