TRAPPIST-1 Archives

An artistic representation of the “hot Saturn” exoplanet, HAT-P-18 b. CREDIT NASA/Eyes on Exoplanets - NASA

Astrogeology, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Press Release, TRAPPIST-1

Hot Saturn Exoplanet HAT-P-18 b And Its Parent Star

by Keith CowingJanuary 11, 2024January 10, 2024

Led by researchers from Université de Montréal’s Trottier Institute for Research on Exoplanets (iREx), a team of astronomers has harnessed the power of the revolutionary James Webb Space Webb Telescope […]

atmospheric abundances for Venus, Earth and Mars.

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1, Water/Hycean Worlds & Oceanography

A Carbon-lite Atmosphere Could Be A Sign Of Water And Life On Other Terrestrial Planets

by Keith CowingDecember 29, 2023December 29, 2023

Scientists at MIT, the University of Birmingham, and elsewhere say that astronomers’ best chance of finding liquid water, and even life on other planets, is to look for the absence, […]

Comparison of the transmission spectrum (at 1 cm−1 resolution, R = 10,000 at 1 μm) for TRAPPIST-1 e with the temperature and gas abundance profiles of the true Earth (cloudy Earth orbiting a G dwarf; cyan line), which is not photochemically self-consistent with the spectrum of TRAPPIST-1, vs. the cloudy preindustrial Earth case, which is photochemically self-consistent with the spectrum of TRAPPIST-1 and has similar clouds (dark-blue line). For the same surface flux, the self-consistent preindustrial Earth produces much stronger CH4 features owing to higher atmospheric abundances under favorable chemistry driven by the TRAPPIST-1 stellar spectrum. The CO2 features for our self-consistent Earth are larger only as a result of requiring a higher abundance to remain temperate. -- Planetary Science Journal

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

Searching For Biosignature Gases With The James Webb Space Telescope

by Keith CowingDecember 3, 2023December 2, 2023

NASA-supported researchers have assessed the capabilities of the James Webb Space Telescope (JWST) to search for gases in planetary atmospheres that could be signs of life.

We select 10 and 5 candidate planets around nearby stars for ELT/HARMONI and ELT/METIS, respectively. As the spatial resolution of ELT/HARMONI is smaller than the plotting range, we only show spatial resolution for ELT/METIS as the vertical dotted blue line. Planets located to the right of the dotted line are suitable planets for ELT/METIS. All colored points are suitable planets for ELT/HARMONI. The size of the colored point is proportional to the planet radius. The color of the point is based on the equilibrium temperature. All colored data points are the candidate planets listed in Table 1. Selection criteria can be found in §2.1. The gray points are other exoplanets from NEA that are less suitable for direct imaging with ELT. -- astro-ph.EP

Astronomy & Telescopes, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Proxima Centauri, Status Report, TRAPPIST-1

Detecting Biosignatures in Nearby Rocky Exoplanets using High-Contrast Imaging and Medium-Resolution Spectroscopy with Extremely Large Telescope

by Keith CowingNovember 30, 2023November 30, 2023

In the upcoming decades, one of the primary objectives in exoplanet science is to search for habitable planets and signs of extraterrestrial life in the universe.

Comparing TRAPPIST-1 planets to Solar System planets (left) and likely rocky exoplanets already observed or planned to be observed by JWST in Cycle 1 and 2 (right). Incident flux is plotted against escape velocity, so that planets in the top left are less likely to retain atmospheres, and planets in the bottom right are more likely to retain atmospheres. Stellar temperature, represented by color, may also play a role in atmosphere retention. Black Xs are placed on the labeled exoplanets which have already been observed to have no thick atmosphere. The gray line in the right panel is the “cosmic shoreline” (Finc ∝ vesc 4 ) presented in Zahnle & Catling (2017). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Status Report, TRAPPIST-1

The Carbon-Deficient Evolution Of TRAPPIST-1c

by Keith CowingNovember 29, 2023November 29, 2023

Transiting planets orbiting M dwarfs provide the best opportunity to study the atmospheres of rocky planets with current facilities.

Tracing a link between two neighbour planet at regular time interval along their orbits, creates a pattern unique to each couple. The six planets of the HD110067 system create together a mesmerising geometric pattern due to their resonance-chain. CREDIT Thibaut Roger/NCCR PlanetS

Astronomy & Telescopes, Exoplanets, -moons, -comets, Press Release, TRAPPIST-1

Six Planets Orbit HD110067 System In A Harmonic Rhythm

by Keith CowingNovember 29, 2023April 14, 2026

An international collaboration between astronomers using the CHEOPS and TESS space satellites, including NCCR PlanetS members from the University of Bern and the University of Geneva, have found a key […]

Upper left panel: Comparison of our work to the model results of Mikal-Evans (2022) who assumed a cloud-less Archean-Earth. Grey shading indicated the wavelength range of the figure below. Lower left panel: The transmission spectra of TRAPPIST-1e observed with HST/WFC3 during two different transits (see Zhang et al. 2018). The green lines show our wet alive model results during the Carrington-like event (solid lines - scenario [5], dashed lines - scenario [6]), while the blue lines correspond to the Archean-Earth scenario of Mikal-Evans (2022). Right panel: Comparison of the corresponding assumed atmospheric temperature profiles. -- astro-ph.EP

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

Impact of Cosmic Rays on Atmospheric Ion Chemistry and Spectral Transmission Features of TRAPPIST-1e

by Keith CowingNovember 10, 2023November 10, 2023

Ongoing observing projects like the James Webb Space Telescope (JWST) and future missions offer the chance to characterize Earth-like exoplanetary atmospheres. Thereby, M-dwarfs are preferred targets for transit observations, for […]

Constraining the surface heterogeneities of a host star. a. A simulated 3.3-d full rotation curve of TRAPPIST-1 (black line) featuring nine transits of six planets (coloured lines). b. A snapshot of the spot distribution at the last rotational phase of the simulation shown in panel a, with the transit chords of planets b, c, d, and e. c. Contaminated transmission spectra for the same transit train of planets b–e (coloured lines). A nominal planet radius of 1 R⊕ (dashed gray line) is used for each planet to ease comparisons of the TLS effect for each planet. d. The residual stellar contamination signals for the simulated transits of planets c–e (coloured lines), after correcting for the TLS effect using the in-transit signal from planet b. A median-subtracted model of an atmosphere (see Figure 2) is shown for comparison (gray dashed line). e. Close-up view of the transit profiles for the four-planet transit train, highlighting repeated occultations of the same active regions by planets b and d as well as c and e, whose transit chords overlap in this simulation. -- astro-ph.EP

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

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

by Keith CowingNovember 1, 2023November 1, 2023

Ultra-cool dwarf stars are abundant, long-lived, and uniquely suited to enable the atmospheric study of transiting terrestrial companions with JWST. Amongst them, the most prominent is the M8.5V star TRAPPIST-1 […]

Illustration of our strategy to detect habitable exoplanetary environment via CO2 depletion. Each of the planets to the right hand side of the star describes a different scenario discussed in the text (along with illustrative atmospheric concentrations). The panel on the left hand side depicts a simulation of the transmission spectrum of the temperate terrestrial planet TRAPPIST-1 f. We explore the detectability of an atmosphere with ∼ 10 JWST/NIRSpec Prism transit observations, the minimum needed to produce a reliable diagnostic. Note that the deviation from a flat signal (no atmosphere) is primarily supported by the strong absorption features of CO2, notably at 4.3 µm (highlighted). Exo-atmospheric models from 142 were used to make that panel. On the lower right hand side, we illustrate a simplified view of a carbon cycle involving surface liquid water and biology sequestering cycle and producing a depletion in atmospheric carbon. Atmospheric concentrations given near the planets are illustrative. astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Atmospheric Carbon Depletion As A Tracer Of Water Oceans And Biomass On Temperate Terrestrial Exoplanets

by Keith CowingOctober 24, 2023October 24, 2023

The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O2, will be challenging to detect with present or upcoming […]

a. Model surface spectral flux, 𝐼𝑠 (𝜆;𝑇𝑠) , for planets within the middle of the habitable zone around parent stars of different effective temperatures, 𝑇𝑠. The spectral fluxes are taken from PHOENIX radiative transfer models (Husser et al. 2013) of surface spectral flux and the habitable distances are estimated according to a simple radiative equilibrium model outlined in the Methodology. A sparse range of temperatures is shown purely for clarity and the vertical dashed lines approximately demarcate the absorption regions for oxygenic and anoxygenic photosynthesis, with the former often referred to as photosynthetically active radiation (PAR). b. A schematic diagram of the concept of a dual-input noise-cancelling antenna. Two sub-populations of pigments with similar (but different) absorption maxima funnel energy to the reaction centre (RC) which oxidizes an electron donor and reduces an acceptor. The two absorbing populations tend to operate in series (e.g. Chl b transferring energy to Chl a in plant antenna complexes) and are subject to both external and internal noise. The former reflects the highly dynamic nature of the light-environment while the latter results from fluctuations of the energy transfer pathways within the antenna. c. An example of the matrix representation of Δ 𝑜𝑝 (𝜆0, Δ𝜆) for a fixed value of absorber width, 𝜎 = 10 nm. Above this is an illustration of two examples of antenna configuration superimposed on the 2800 K spectrum (dark red). 𝑇 = 2800 K is chosen here purely for illustrative purposes as it exhibits many sharp bands of optimal (and extremely sub-optimal) antenna configurations. Note the distinction between the standard deviation or ’width’, 𝜎, and the Full Width at Half Maximum, Γ 2.63𝜎 of the Gaussian peak. -- astro-ph.SR

Biochemistry & Organic Chemistry, Biophysics, Exoplanets, -moons, -comets, Gaia - Planetary Perspectives, Habitable Zones, Plant Biology, Status Report

Photosynthesis Under A Red Sun: Predicting The Absorption Characteristics Of An Extraterrestrial Light-harvesting Antenna

by Keith CowingOctober 10, 2023October 9, 2023

Here we discuss the feasibility of photosynthesis on Earth-like rocky planets in close orbit around ultra-cool red dwarf stars. Stars of this type have very limited emission in the photosynthetically […]

TRAPPIST-1

Hot Saturn Exoplanet HAT-P-18 b And Its Parent Star

A Carbon-lite Atmosphere Could Be A Sign Of Water And Life On Other Terrestrial Planets

Searching For Biosignature Gases With The James Webb Space Telescope

Detecting Biosignatures in Nearby Rocky Exoplanets using High-Contrast Imaging and Medium-Resolution Spectroscopy with Extremely Large Telescope

The Carbon-Deficient Evolution Of TRAPPIST-1c

Six Planets Orbit HD110067 System In A Harmonic Rhythm

Impact of Cosmic Rays on Atmospheric Ion Chemistry and Spectral Transmission Features of TRAPPIST-1e

A Roadmap To The Efficient And Robust Characterization Of Temperate Terrestrial Planet Atmospheres With JWST

Atmospheric Carbon Depletion As A Tracer Of Water Oceans And Biomass On Temperate Terrestrial Exoplanets

Photosynthesis Under A Red Sun: Predicting The Absorption Characteristics Of An Extraterrestrial Light-harvesting Antenna

Curiosity Mars Rover Discovers A Field Of Honeycomb Textures

Viking Science

Constraining The Lives And Times Of Exoplanets Through Evolutionary Bayesian Retrievals

Project Hephaistos — III. Characterizing Anomalous Infrared Sources Identified As Dyson-sphere Candidates

SCoRE: The Surface Composition Of Rocky Exoplanets