TRAPPIST-1 b Archives - Page 2 of 4 - Astrobiology

Range of best-fit phase curve and eclipse models for TRAPPIST-1 b and c. The detrended data are shown with gray dots and binned data with black dots. Red curves show the light curve model for each JWST program that observed TRAPPIST-1 b and c at 15µm using MIRI F1500W; the shading spans the range of models drawn from the posterior distribution of the day flux, night flux and phase offset for planets b and c from Analysis # 1 at 2-σ. The top panel shows the phase curve from GO 3077; the second row displays the five visits from GO 1177 (PI: Greene); and the third row presents the four visits from GO 2304 (PI: Kreidberg), along with a zoom-in on the double occultation observed in GO 3077. The expected transit and eclipse timings for each planet from [19] are shown in vertical dashed and plain lines respectively (purple for b, orange for c, and green for g). -- astro-ph.EP

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

First JWST Thermal Phase Curves Of Temperate Terrestrial Exoplanets Reveal No Thick Atmosphere Around TRAPPIST-1 b and c

by Keith CowingSeptember 3, 2025September 3, 2025

We report JWST/MIRI 15 μm phase curves of TRAPPIST-1 b and c, revealing thermal emission consistent with their irradiation levels, assuming no efficient heat redistribution.

This artist’s concept depicts planet TRAPPIST-1 d passing in front of its turbulent star, with other members of the closely packed system shown in the background. Credit: NASA, ESA, CSA, J. Olmsted (STScI)

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

Webb Narrows Atmospheric Possibilities For Earth-sized Exoplanet TRAPPIST-1 d

by Keith CowingAugust 13, 2025August 13, 2025

The exoplanet TRAPPIST-1 d intrigues astronomers looking for possibly habitable worlds beyond our solar system because it is similar in size to Earth, rocky, and resides in an area around […]

Joint posterior constraints on the surface partial pressure of key atmospheric absorbers for atmospheric scenarios similar to solar system terrestrials, with N2 as the background gas. The color shadings correspond to the posterior probability mass, and the contours highlight the 68% and 95% confidence regions from the joint retrieval in each case. The absorber in the N2-background atmosphere is labeled in the top right corner of each panel. The dashed-dotted, dashed, and solid sienna lines correspond to an atmospheric surface pressure of 0.1, 1, and 10 bar. We illustrate where typical models of Archean Earth (AE), Modern Earth (ME), and compositions for Titan (T), early Mars (eMa), Mars (Ma), and Venus (V; Encrenaz & Coustenis 2018) approximately lie relative to our constraints for TRAPPIST-1 d. Star markers correspond to specific cloudy cases, where the planet is modeled as either cloudy or cloud-free (for Titan, Modern Earth, and Venus). For the N2-H2O case, we show as a black dotted line the limit of pressures that would be cut off by refraction in a 11 bar atmosphere (10 bar H2O+1 bar N2). For thinner atmospheres, the impact of refraction on atmosphere detectability is even weaker. -- astro-ph.EP

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

Strict Limits On Potential Secondary Atmospheres On The Temperate Rocky Exo-Earth TRAPPIST-1 d

by Keith CowingAugust 13, 2025August 13, 2025

The nearby TRAPPIST-1 system, with its seven small rocky planets orbiting a late-type M8 star, offers an unprecedented opportunity to search for secondary atmospheres on temperate terrestrial worlds.

Stellar flares observed in JWST/NIRISS time-series spectroscopy of TRAPPIST-1. Each column shows one flare event during transits of the TRAPPIST-1c or TRAPPIST-1f planets. Tow row: Light curves with the total flux (integrated over the full spectral range and normalized to the mean out-of-transit flux). Colored points indicate pre-flare (green), flare (orange), maximum flare light (red), and post-flare (blue) phases. Green and blue dashed lines mark the average pre- and post-flare flux levels. Middle row: Light curves of the normalized Hα flux. Bottom row: Time-resolved spectrograms (wavelength vs. time) normalized to the pre-flare spectrum. The shaded blue region shows the drop in flux caused by the planetary transit. For comparison, the time axis in all panels are aligned such that t = 0 corresponds to the beginning of the maximum flare light phase. In all four events, the total flux in the post-flare phase is systematically elevated relative to the pre-flare level. -- astro-ph.EP

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Magnetic Fields, Electromagnetism, bioelectricity,, Press Release, Radiation, Space Weather & Heliophysics, TRAPPIST-1

Flares On TRAPPIST-1 Reveal The Spectrum Of Magnetic Features On Its Surface

by Keith CowingAugust 8, 2025August 8, 2025

TRAPPIST-1 is an M8 dwarf hosting seven known exoplanets and is currently one of the most frequently observed targets of the James Webb Space Telescope (JWST).

Best-fit model to an empirical transmission spectrum of the cloudless Earth in units of scale height, H (adapted from (40)). Different colors indicate the contributions from various molecules. Despite its relatively low abundance, CO2 has the most prominent spectral features (at 2.7 and 4.3 µm), making it an ideal molecule to search for in exoplanet atmospheres. The strength of different absorption peaks is sensitive to the underlying atmospheric composition and detailed atmospheric modeling can constrain the abundances of individual absorbing species (which may differ from those of the Earth). This figure neglects the effects of refraction, which effectively blocks transmission below roughly 1.5 scale heights for Earth-Sun analog systems (planets orbiting M-dwarfs are less strongly affected) (41). -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Press Release

A First Look At Rocky Exoplanets With JWST

by Keith CowingJuly 3, 2025July 3, 2025

Rocky exoplanet characterization has been a top priority for early James Webb Space Telescope (JWST) science operations. Several milestones have been achieved, including the most precise rocky planet transmission spectra […]

Astronomy & Telescopes, Atmospheres, Climate, Weather, Habitable Zones, Space Weather & Heliophysics, Status Report, TRAPPIST-1

Hubble’s Multi-Year Search for Exospheres in the TRAPPIST-1 System Reveals Frequent Microflares

by Keith CowingJune 17, 2025June 17, 2025

Ly-α observations provide a powerful probe of stellar activity and atmospheric escape in exoplanetary systems.

JWST GO time allocation for exoplanet science on different Cycles. Representation of the total General Observer (GO) allocated time for exoplanet science on JWST Cycle 1 (released on March, 2021, i.e., pre-launch), Cycle 2 (released on May 2023), Cycle 3 (released on February, 2024) and Cycle 4 (released on March, 2025). The percentage of all telescope time spent on exoplanet science for a given Cycle is indicated on top of this illustration (e.g., Cycle 1 comprised 23% of time on the telescope devoted to exoplanet science). The purple shading corresponds to the share allocated to transiting exoplanet science while the orange shading corresponds to highcontrast exoplanet science performed with JWST. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Gas Giants, Status Report

Highlights from Exoplanet Observations by the James Webb Space Telescope

by Keith CowingMay 28, 2025May 28, 2025

The James Webb Space Telescope (JWST) has started a revolution in exoplanetary science.

Surface temperature (straddling 0◦C), total cloud cover (%), net outgoing thermal radiation (W m−2 ), and cloud water content (kg m−2 ) for four of the simulations listed in Table 1. Simulations are displayed from dry (Sim 01: Arid-Venus), semidry 10 m GEL (Sim 02: 10 m-Venus), Earth-like 310 m GEL (Sim 03: 310 m-Venus) and an aquaplanet (Sim 06). Sims 01–03 are 1 bar N2 dominated with 400ppmv CO2. Sim 06 is N2-dominated, but the only greenhouse gas is H2O following Wolf (2017). Cloud coverage is fairly low in Sims 01–02 as expected given limited surface reservoirs and cloud water content (rightmost column), and is much higher for Sims 03 and 06. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Press Release, TRAPPIST-1, Venus

TRAPPIST-1 d: Exo-Venus, Exo-Earth or Exo-Dead?

by Keith CowingFebruary 10, 2025February 10, 2025

TRAPPIST-1 d is generally assumed to be at the boundary between a Venus-like world and an Earth-like world, although recently published works on TRAPPIST-1 b and c raise concerns that […]

Normalized white light curves of TRAPPIST-1 c and TRAPPIST-1 b observed with JWST/NIRSpec PRISM during their quasi-simultaneous transits on July 9, 2024. Top panel: A schematic of the geometry of the quasi-simultaneous transits is displayed at the top. The blue circles represent the data points after removing the systematics model (a combination of a linear slope and a Gaussian Process, see Section 3.2). The solid black line indicates the fitted transit model. The data have been binned in time from the original 10,208 integrations to the 341 points shown here to accommodate the computation of the Gaussian Process systematics model. Horizontal lines labeled S1 through S5 mark the time bins used in the out-of-transit stellar analysis (see Section 3.1). The inset displays a histogram of the residuals after subtracting the combined transit and systematics model, compared to a Gaussian distribution with a standard deviation equal to the mean measurement error plus a fitted white noise term. Bottom panel: Residuals after subtracting both the transit and systematic models. -- astro-ph.EP

Astrochemistry, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biophysics, Imaging & Spectroscopy, Interstellar, Status Report

Stellar Contamination Correction Using Back-to-Back Transits of TRAPPIST-1 b and c

by Keith CowingDecember 24, 2024December 24, 2024

Stellar surface heterogeneities, such as spots and faculae, often contaminate exoplanet transit spectra, hindering precise atmospheric characterization.

Qmax (Eq. 14) for the population of exoplanets from the exoplanet.eu database, as a function of the orbital distance and the stellar mass. A given rotation rate has been assumed for all stars in each panel, to estimate their magnetic field and the ambient magnetic field strength at the orbit of the planet. Trappist-1 b and π men c are highlighted by the red square in the left and right panels, respectively. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Magnetic Fields, Electromagnetism, bioelectricity,, Space Weather & Heliophysics, Status Report

Ohmic Heating In The Upper Atmosphere of Hot Exoplanets The Influence of a Time-varying Magnetic Field

by Keith CowingDecember 22, 2024December 22, 2024

Exoplanets on close-in orbit are subject to intense X-ray and ultraviolet (XUV) irradiation from their star. Their atmosphere therefore heats up, sometimes to the point where it thermally escapes from […]