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

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.

Water cloud horizontal and vertical distributions. Water cloud column (a) in latitude vs longitude coordinates and (b) tidallylocked coordinates (b). Water cloud content vertical distribution (c) as a function of tidally-locked latitude (averaged over all tidallylocked longitudes). The plots were computed for an initially hot and steamy 2 R⊕ planet (with a 10 bar of H2O + 1 bar of N2 atmosphere) synchronously rotating (fixed rotation period of 60 Earth days) around a M3 star, and forced to an ISR of 500 W m−2 (simulation M3-YANG-1). The outputs were averaged over 250 Earth days. For reference, insolation is 340.5 W m−2 on present-day Earth. Wind fields are superimposed on the plots. Winds are plotted at a pressure of ∼ 50 Pa in panels a and b, and averaged over all tidally-locked (TL) longitudes in panel c. -- astro-ph.EP

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

Water Condensation Zones Around Main Sequence Stars

by Keith CowingAugust 29, 2023August 29, 2023

Understanding the set of conditions that allow rocky planets to have liquid water on their surface — in the form of lakes, seas or oceans — is a major scientific […]

Some calculated properties from the slowing down of photoelectrons. Top: Fraction of the photoelectron initial energy E0 that is transferred to the gas in elastic collisions. Bottom: Number of secondary ions created by a photoelectron of initial energy E0, normalized by E0. The three color-style combinations refer to pure H (black, long dashed), pure O (black, dotted), and an O-H mixture with fOn/Hn=1/2 (blue, solid). For each mixture, the four curves that are displayed (distinguishable by their thickness) refer to fractional ionizations log10(xe)=−1 (thickest), −2, −3, and −4 (thinnest). Although not shown for the sake of clarity, the Eelas/E0 ratio for E0≳100 eV for pure H becomes essentially independent of fractional ionization at xe

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Status Report, TRAPPIST-1, Water/Hycean Worlds & Oceanography

Heating And Ionization By Non-thermal Electrons In The Upper Atmospheres Of Water-rich Exoplanets

by Keith CowingAugust 14, 2023August 14, 2023

Context. The long-term evolution of an atmosphere and the remote detectability of its chemical constituents are susceptible to how the atmospheric gas responds to stellar irradiation. The response remains poorly […]

The eclipse spectra of various models run in this study. We show: a suite of atmospheric models that are 1-σ consistent with the observation (top left); bare surface models, which are all consistent with the observation (top right); 100 % CO2 atmospheres models at various surface pressures (bottom left); and models with surface pressures of 0.1 bar, varying the compositions (bottom right). The compositions denote that the first species is the dominant species, with the second species in indicated trace amounts. The binned depths at F1500W and F1280W are shown as markers, as well as each bandpass function weighted by the stellar spectrum. We also show, in dashed lines, the eclipse depths resulting from blackbodies at 509 K (blue) and 400 K (red), corresponding to no redistribution (f = 2/3) and full redistribution (f = 1/4), respectively. On the upper right panel, dashed lines indicate grey albedo surface models. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Status Report, TRAPPIST-1

Constraining the Thickness of the Atmosphere of TRAPPIST-1 b from its JWST Secondary Eclipse Observation

by Keith CowingMay 17, 2023May 17, 2023

Recently, the first JWST measurement of thermal emission from a rocky exoplanet was reported. The inferred dayside brightness temperature of TRAPPIST-1 b at 15 μm is consistent with the planet […]

TRAPPIST-1 b F1500W measured flux and spectral models. The blackbody curves represent the measured TB = 503 K dayside temperature, the 508 K apparent dayside temperature predicted for zero heat redistribution and no internal heating, and Teq = 400 K temperature for isotropic redistribution of stellar heating. The flux expected in the upcoming observations in the MIRI F1280W filter is also shown assuming the planet emits like a TB = 503 K blackbody. The widths of the F1280W and F1500W markers represent their transmission half-amplitude bandpasses, and the vertical error bar of the F1500W point represents its 1σ uncertainty. Emergent spectra from 93 bar CO2 and 10 bar outgassed O2 with 0.5 bar CO2 atmospheres are also plotted [20, 33]. -- astro-ph.EP

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

Thermal Emission From The Earth-sized Exoplanet TRAPPIST-1 b Using JWST

by Keith CowingMarch 27, 2023March 27, 2023

The TRAPPIST-1 system is remarkable for its seven planets that are similar in size, mass, density, and stellar heating to the rocky planets Venus, Earth, and Mars in our own […]

TRAPPIST-1 b

Astronomy & Telescopes, Exoplanets, -moons, -comets, Habitable Zones, Imaging & Spectroscopy, Press Release, TRAPPIST-1

Webb Measures The Temperature Of Rocky Exoplanet TRAPPIST-1 b

by Keith CowingMarch 27, 2023March 27, 2023

An international team of researchers has used the NASA/ESA/CSA James Webb Space Telescope to measure the temperature of the rocky exoplanet TRAPPIST-1 b.