TRAPPIST-1f Archives - Astrobiology

Joining of the inner and outer subsystems. The evolution of the semi-major axes is shown with continuous coloured lines for all planets, which are also labelled by circles whose size reflect the observed size of the planets. In our favoured scenario, planet e followed the inner edge while planets b, c and d were in the inner cavity. Planets f, g and h join the system later, undergoing inward disc-driven migration (the disc is depicted by the top shaded area, with the lighter shading on the right indicating that the disc will eventually disperse). Since planet g is more massive than f and h, it is likely to capture f in resonance (the 4:3 being the favoured commensurability [5]) and the two planets migrate in together. When f reaches the 3:2 resonance with e, the combined push from g-f is sufficient to dislodge planet e from the inner edge (shown as a blue line enclosing the top shaded area). Driven by a full OLT, the orbit of planet e decays faster than f and g, approaching the 3:2 resonance with d. Planet h is the last one to migrate in and capture g in the 3:2 resonance to complete the chain. -- astro-ph.EP

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

Forming The Trappist-1 System In Two Steps During The Recession Of The Disc Inner Edge

by Keith CowingAugust 27, 2024August 27, 2024

Trappist-1 hosts 7 planets where period ratios of neighbouring pairs are close to the 8:5, 5:3, 3:2, 3:2, 4:3, and 3:2 ratios in increasing distance from the star. The Laplace […]

Oxygen retention efficiency as a function of initial water content in TO. Top Row: Interior planets, T1-b, c, and d. Bottom Row: Outer planets, T1-e, f, g, and h. Coloring shows the percentage of simulations at a particular initial water content that fell in a given oxygen retention efficiency bin (e.g., each column corresponds to one initial water content and sums to 100%). Contours are given for the 50th percentile values (solid white lines) and the 1σ confidence region (dashed white lines). -- astro-ph.EP

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

The Implications of Thermal Hydrodynamic Atmospheric Escape on the TRAPPIST-1 Planets

by Keith CowingMay 7, 2024May 7, 2024

JWST observations of the 7-planet TRAPPIST-1 system will provide an excellent opportunity to test outcomes of stellar-driven evolution of terrestrial planetary atmospheres, including atmospheric escape, ocean loss and abiotic oxygen […]

Combined transmission spectrum LHS1140b obtained with NIRISS SOSS on December 1st and 26th 2023 overlaid with HST observations (solid grey points; Edwards et al. 2021). The orange 2-envelope is the best TLS model dominated by facula. The dashed line is the predicted GCM model of the mini-Neptune scenario of Cadieux et al. (2024); this model is excluded at more than 5  (Cadieux et al., in prep). -- astro-ph.EP

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

Do Temperate Rocky Planets Around M Dwarfs have an Atmosphere?

by Keith CowingMarch 20, 2024

Detecting an atmosphere on nearby temperate planets is one of the most important scientific objectives of the Webb mission, an endeavour in practice limited to a handful of well-characterized planets: […]

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, […]

Explosive cryovolcanism in the form of geyser-like plumes on two of our solar system's ocean worlds. Left: Cryovolcanic eruptions at the south pole of Saturn's moon Enceladus (credit: NASA/JPL-Caltech/SSI). Right: Hubble Space Telescope UV observations of cryovolcanic eruptions at the south pole of Jupiter's moon Europa (credit: NASA/L. Roth). By facilitating the transport of liquid water and energy between their interiors and surfaces, similar activity could create habitable environments on cold ocean planets. - NASA/Astrophysical Journal

Astrogeology, Biochemistry & Organic Chemistry, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Press Release, Proxima Centauri, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Some Icy Exoplanets May Have Habitable Oceans And Geysers

by Keith CowingDecember 13, 2023

A NASA study expands the search for life beyond our solar system by indicating that 17 exoplanets (worlds outside our solar system) could have oceans of liquid water, an essential […]

Broadband light curves of the flare-affected transits of TRAPPIST-1b and f. The transit models are shown in orange, and the exponential fit to the integrations in both the transit and flare is shown in blue. The exponential fit is necessary to determine the shape of the transit light curve. As shown in the O-C diagrams at the bottom, we use an initial guess of c1 and c2 to fit the exponential, then subtract the exponential to obtain final values of c1 and c2. We note c1 and c2 represent the coefficients of the quadratic limb darkening equation. The first and third O-C diagrams are directly comparable and show the light curve with the final transit model removed. The middle O-C diagram shows an intermediate step in the determination of the TRAPPIST-1f transit model fit in which the initial guess on the transit model is subtracted prior to fitting and subtracting the exponential. The residuals of the middle panel therefore show the quality of the exponential fit. -- astro-ph.SR

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

Characterizing The Near-infrared Spectra Of Flares From TRAPPIST-1 During JWST Transit Spectroscopy Observations

by Keith CowingOctober 9, 2023October 9, 2023

We present the first analysis of JWST near-infrared spectroscopy of stellar flares from TRAPPIST-1 during transits of rocky exoplanets. Four flares were observed from 0.6–2.8 μm with NIRISS and 0.6–3.5 […]

Top: Top-of-atmosphere number flux from the Sun and TRAPPIST-1 (left y-axis). Also co-plotted are the photolysis cross-sections of CO2 (right abscissa). Bottom: CO2 cross-sections weighted by the stellar emission of TRAPPIST-1 and the Sun. The bluer spectrum of TRAPPIST-1 increases the weight of shortwave σCO2 , which is larger, driving an increase in σUV,g. -- astro-ph.EP

Atmospheres, Climate, Weather, Biochemistry & Organic Chemistry, Exoplanets, -moons, -comets, Habitable Zones, Status Report

A Re-Appraisal of CO/O2 Runaway On Habitable Planets Orbiting Low-Mass Stars

by Keith CowingJuly 19, 2023July 19, 2023

Efforts to spectrally characterize the atmospheric compositions of temperate terrestrial exoplanets orbiting M-dwarf stars with the James Webb Space Telescope (JWST) are now underway. Key molecular targets of such searches […]