TRAPPIST-1 Archives

Temperature distributions and thermal phase curves of the TRAPPIST-1 e system. Panel (a): Snapshot of the effective emission temperature of TRAPPIST-1 e.

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

The Influence Of Hypothetical Exomoons On Planetary Thermal Phase Curves

by Keith CowingMarch 22, 2026March 22, 2026

More than 200 moons exist in our Solar System, yet no exomoon has been confirmed to date. While the innermost two planets of the Solar System lack natural satellites and […]

A diagram depicting habitable zone boundaries across star type with rocky exoplanets from Bohl et al. (2026). The boundaries of the habitable zone shift based on star colour, since different wavelengths of light will heat a planet's atmosphere differently. Credit Gillis Lowry / Pablo Carlos Budassi Licence type Attribution (CC BY 4.0)

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Gaia Mission, Habitable Zones, Imaging & Spectroscopy, People Of Astrobiology, Press Release, TRAPPIST-1

Where To Find Other Earths? New List Narrows Down The Targets

by Keith CowingMarch 20, 2026March 20, 2026

New Cornell research – co-authored by an undergraduate and two recent alumni – will help exoplanet scientists pinpoint the most likely places to look for life in the universe out […]

Illustration of some of the multi-modal factors that may contribute to an IHZ in our solar system, overlaid on traditional habitable zones: the circumstellar habitable zone and the zone where closed icy ocean worlds can exist. -- astro-ph.EP

Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Radiation, Space Weather & Heliophysics, Status Report, TRAPPIST-1

The Interplanetary Habitable Zone

by Keith CowingFebruary 17, 2026February 17, 2026

The concept of a system-wide measure of the sustainment of life (habitability) for space-faring interplanetary species is introduced and explored.

Color phase curves (CPCs) for the sum of planets ’b’ and ’d’ in the Proxima Centauri system. The CPC is the ratio of the flux in the 21 µm to 12.8 µm JWST/MIRI filters, normalized to the stellar flux, with the median value subtracted from the normalized ratio. The CPCs are the sum of both planets, and are shown here for the 2027 visibility period for JWST (lighter when not visible). Two cases are shown: using a hot rock model for ’b’, and a GCM (see text). Planet ’d’ is modeled as a hot rock in both cases.

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

The Third Option: Color Phase Curves to Characterize the Atmospheres of Temperate Rocky Exoplanets

by Keith CowingFebruary 9, 2026

Detecting and characterizing the atmospheres of rocky exoplanets has proven to be challenging for JWST. Transit spectroscopy of the TRAPPIST-1 planets has been impacted by the effects of spots and […]

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.

(a,b) An example of the transmittance spectra taken with the full-scan mode of the SO channel of TGO/NOMAD. (c,d) An example of the transmittance spectra taken with the full-scan mode of the UVIS channel. -- astro-ph.EP

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

Anatomy Of Empirical Transit Spectra Of Mars Based On TGO/NOMAD

by Keith CowingJanuary 16, 2026January 16, 2026

Transit spectroscopy is a powerful tool for probing atmospheric structures of exoplanets. Accurately accounting for the effects of aerosols is key to reconstructing atmospheric properties from transit spectra, yet this […]

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 […]

TRAPPIST-1

The Influence Of Hypothetical Exomoons On Planetary Thermal Phase Curves

Where To Find Other Earths? New List Narrows Down The Targets

The Interplanetary Habitable Zone

The Third Option: Color Phase Curves to Characterize the Atmospheres of Temperate Rocky Exoplanets

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

Anatomy Of Empirical Transit Spectra Of Mars Based On TGO/NOMAD

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

PJ Harvey Announces New Song “Voyager”

Fifty Years after Viking: The Promise of Solar System Microbiology and Microbial Ecology

Characterising Transiting Exoplanets At Long Orbital Period: Lessons Learned For PLATO From 10 Years Of Monitoring The HIP41378 System

Implications Of Self-consistent H2O Ice Optical Constants On Radiative Transfer Models Of Disks

The GAPS Programme at TNG LXXIV. A Reanalysis Of The Planetary Systems TOI-1272 And TOI-1694 With HARPS-N And Retraction Of The Planetary Interpretation Of TOI-1272 c