TRAPPIST-1 Archives

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 […]

STEREO A/SWAVES (location A in red), Wind/WAVES (location in green), and STEREO B/SWAVES (location B in blue) dynamic radio spectra from ≈ 10 MHz down to 10 kHz. The visible IP type II burst lanes are indicated with arrows. -- physics.space-ph

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

Separating The Effects Of Earthside And Far Side Solar Events. A Case Study

by Keith CowingOctober 10, 2023October 10, 2023

On 8 November 2013 a halo-type coronal mass ejection (CME) was observed, together with flares and type II radio bursts, but the association between the flares, radio bursts, and the […]

Evolution of the inertial-frame mode frequencies σ in units of the dynamical frequency Ωdyn (top panel) and the absolute value of the ℓ = m = 2 tidal overlap coefficients Qℓ,m (bottom panel) for the set of f-modes and i-modes we include during the pre-MS to MS evolution of the Prot,0 = 5 day (left) and 1 day (right) sets of stellar models. In the bottom panel, a subset of these modes are plotted. For the Prot,0 = 1 day models, i-modes that experience avoided crossings are plotted with a circle marker in the bottom panel. -- astro-ph.EP

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

Tidal Migration Of Exoplanets Around M-dwarfs: Frequency-dependent Tidal Dissipation

by Keith CowingOctober 10, 2023October 10, 2023

The orbital architectures of short-period exoplanet systems are shaped by tidal dissipation in their host stars.

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 […]

The evolution of M dwarf X-ray activity over time. Early M dwarfs are plotted on the left, and mid-late M dwarfs on the right. Lighter-colored error bars indicate when the ‘average’ uncertainty value was applied to a target for fitting purposes. A two-component, segmented linear model was applied to each subset and is plotted. Each subset shows an initial “saturation phase” where high activity levels are sustained for a period of time, before an inflection point is reached. After this, the activity decreases at an accelerated rate. It is worth noting that many studies assume a constant level of activity during the saturation phase, where our fits indicate that a slight decrease occurs. The saturation phase is found last ∼470 Myr for the early M dwarfs and ∼2.1 Gyr for the mid-late M dwarfs. -- astro-ph.EP

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

Living With A Red Dwarf: X-ray, UV, And Ca II Activity-Age Relationships Of M Dwarfs

by Keith CowingOctober 9, 2023October 9, 2023

The vast majority of stars in the nearby stellar neighborhood are M dwarfs. Their low masses and luminosities result in slow rates of nuclear evolution and minimal changes to the […]

Joint constraints on the H2/He abundance and the atmospheric pressure on TRAPPIST-1 b resulting from the sequential fit of the stellar contamination and planetary atmosphere. The color shading illustrates the posterior probability density, where darker colors correspond to higher probabilities. Contours indicate the 1σ, 2σ, and 3σ Bayesian credible regions. The displayed posterior probability is marginalized over the H2O, CH4, CO, CO2, NH3, and N2 abundances. Hydrogen-dominated scenarios with high-altitude clouds are at the top left corner of the plot and cloud-free, volatile-rich, high-mean-molecular-mass atmospheres are at the bottom right. Any hydrogen-rich atmospheres without high-altitude clouds, at the bottom left, are robustly ruled out. The second horizontal axis at the top shows the mean molecular mass representative for a pure H2/H2O atmosphere. -- University of Michigan

Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1

JWST’s First Spectrum Of A TRAPPIST-1 Planet

by Keith CowingOctober 8, 2023October 8, 2023

In a solar system called TRAPPIST-1, 40 light years from the sun, seven Earth-sized planets revolve around a cold star.

Image description: Infographic titled, “Rocky Exoplanet TRAPPIST-1 b Dayside Temperature Comparison, MIRI F1500W” showing five planets plotted along a horizontal temperature scale: Earth, TRAPPIST-1 b, Mercury, and two different models of TRAPPIST-1 b. The temperature scale is labeled in kelvins and degrees Fahrenheit, and ranges from 0 kelvins (negative 459 degrees Fahrenheit) at the left to 800 kelvins (980 degrees Fahrenheit at the right). The planets are plotted along the temperature scale at the following temperatures: Earth Measured at 290 kelvins (60 degrees Fahrenheit); TRAPPIST-1 b Measured at about 500 kelvins and 445 degrees Fahrenheit; “Mercury Measured” at 700 kelvins (800 degrees Fahrenheit). TRAPPIST-1 b Model with atmosphere is plotted at 400 kelvins (260 degrees Fahrenheit); TRAPPIST-1 b Model with no atmosphere is plotted at about 510 kelvins and 455 degrees Fahrenheit. TRAPPIST-1 b Measured is plotted at almost the same temperature as TRAPPIST-1 b Model with no atmosphere.

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

Webb Measures The Temperature Of Rocky Exoplanet TRAPPIST-1 b

by Keith CowingOctober 2, 2023

Webb measured the dayside temperature of rocky exoplanet TRAPPIST-1 b and found it to be about 450 degrees F (227 degrees C), suggesting it has no significant atmosphere.

Best-fit system in each modeling scenario compared to the true TRAPPIST-1 system using only Filippazzo et al. (2015) priors. The symbol size corresponds to the planet size, and the color indicates albedo. Horizontal bars indicate the uncertainty on a planet’s semi-major axis. Each modeling scenario is labeled with the number of planets included, the computed evidence, and its significance against the best-fit model. We use transparency to demonstrate which models are ruled out by > 3σ confidence. The vertical dashed lines indicate the limits of our semi-major axis bounds. -- astro-ph.EP

Astronomy & Telescopes, Status Report, TRAPPIST-1

On the Effectiveness of the Planetary Infrared Excess (PIE) Technique to Retrieve the Parameters of Multiplanet Systems around M dwarfs: A Case Study on the TRAPPIST-1 System

by Keith CowingOctober 1, 2023October 1, 2023

The planetary infrared excess (PIE) technique has the potential to efficiently detect and characterize the thermal spectra of both transiting and non-transiting exoplanets. However, the technique has not been evaluated […]

TRAPPIST-1

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

Separating The Effects Of Earthside And Far Side Solar Events. A Case Study

Tidal Migration Of Exoplanets Around M-dwarfs: Frequency-dependent Tidal Dissipation

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

Living With A Red Dwarf: X-ray, UV, And Ca II Activity-Age Relationships Of M Dwarfs

JWST’s First Spectrum Of A TRAPPIST-1 Planet

Webb Measures The Temperature Of Rocky Exoplanet TRAPPIST-1 b

On the Effectiveness of the Planetary Infrared Excess (PIE) Technique to Retrieve the Parameters of Multiplanet Systems around M dwarfs: A Case Study on the TRAPPIST-1 System

Giving NASA’s SciX A Quick Astrobiology Roadtest

An Ultraviolet Instrument On The Habitable Worlds Observatory: Considerations and Capability Trades On The Multi-Object, Integral-field, and High-resolution Modes Of A Potential UVI

The Hydrological Cycle and Circulation of Tidally-Locked Planets with A Finite Moisture Inventory

Fermentation Heterotrophy Can Reproduce Enceladus’s H2 And CH4 Under Limited Serpentinization

Perseverance Mars Rover Sets Off-World Record for Total Distance Driven