terrestrial exoplanet Archives - Page 3 of 4 - Astrobiology

Emission spectra for different atmospheric scenarios. The curves show the planetary flux to stellar flux ratio in ppm as a function of wavelength in µm. In all cases we considered a surface albedo of 0.1, heat redistribution factor based on Koll (2022) and colour-coded in the legend, ordered by the corresponding location of the model in the 15 µm bandpass. Only the no atmosphere cases have an albedo of 0 and 0.1 and zero heat redistribution. The grey dashed line and the shaded area is the blackbody emission at 1024 K and 1σ confidence interval. The black dot is the measured joint occultation depth with its 1σ uncertainty, while the pink diamond is the measured value from the independent analysis using Frida. The blue curve and light blue shaded area at the bottom is the response function of the F1500W filter. -- astro-ph.EP

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

Hot Rocks Survey II: The Thermal Emission Of TOI-1468 b Reveals A Hot Bare Rock

by Keith CowingMarch 27, 2025March 27, 2025

Terrestrial exoplanets orbiting nearby small, cool stars known as M dwarfs are well suited for atmospheric characterisation. Given the strong XUV irradiation from M dwarf host stars, orbiting exoplanets are […]

(Top) CO2 cross-section prescriptions from 120-240 nm. (Bottom) Spectral energy distribution of the stars modeled in this study, from 120-240 nm. -- astro-ph.EP

Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exploration Gear & Tech, Habitable Zones, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

The Impact of Extended CO2 Cross Sections on Temperate Anoxic Planet Atmospheres

by Keith CowingJanuary 20, 2025January 19, 2025

Our interpretation of terrestrial exoplanet atmospheric spectra will always be limited by the accuracy of the data we use as input in our forward and retrieval models.

LEFT: Instantaneous surface temperature for Proxima Centauri b in a 3:2 SOR for (a) the substellar point at 0◦ longitude and (b) the substellar point at 180◦ longitude. The horizontal wind vectors are again shown at P≈250 hPa. RIGHT Instantaneous vertically integrated ozone column density for Proxima Centauri b in a 3:2 SOR for (a) daytime on the 0◦ hemisphere and (b) daytime on the 180◦ hemisphere. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Habitable Zones, Imaging & Spectroscopy, Proxima Centauri, Status Report

Earth-like Exoplanets In Spin-orbit Resonances: Climate Dynamics, 3D Atmospheric Chemistry, and Observational Signatures

by Keith CowingOctober 29, 2024October 29, 2024

Terrestrial exoplanets around M- and K-type stars are important targets for atmospheric characterisation. Such planets are likely tidally locked with the order of spin-orbit resonances (SORs) depending on eccentricity. We […]

Countour plot of the S/N for a 1500 K planet orbiting AD Leonis M-dwarf star (orbit of 0.13 AU) at different luminosity (y-axis) and distance (x-axis), after one hour of integration time. The horizontal yellow line indicates the current AD Leonis to sun luminosity ratio. -- astro-ph.EP

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

Large Interferometer For Exoplanets (LIFE). XIV. Finding Terrestrial Protoplanets In The Galactic Neighborhood

by Keith CowingOctober 18, 2024October 18, 2024

The increased brightness temperature of young rocky protoplanets during their magma ocean epoch makes them potentially amenable to atmospheric characterization to distances from the solar system far greater than thermally […]

Left panel: JWST/MIRI photometry eclipse depth measurement at 15 µm (black data point) in context with different atmospheric models (coloured full lines), and airless blackbody (BB) models for different Bond albedos (AB; brown dashed and dotted lines). Tday is the corresponding dayside brightness temperature as computed with Equation (2). All atmospheric scenarios are computed with AB = 0.1 and using the "f-approximation formula" based on Koll (2022). N2 and O2 are both spectrally inactive (no significant absorption features) at these wavelengths, thus yielding nearly identical thermal emission spectra. Only the N2/CO2 scenarios are plotted for simplicity. The result from the Eureka! reduction is also shown (orange data point). Right panel: Atmospheric models (coloured circles) and atmosphere-less models (squares) from the left panel averaged over the F1500W bandpass. The gray shaded region represents the lower and upper error on the photometric measurement (solid line) obtained through a simple mean of both pipeline results. -- astro-ph.EP

Astrogeology, Astronomy & Telescopes, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Imaging & Spectroscopy, Status Report

Hot Rocks Survey I: A Shallow Eclipse For LHS 1478 b

by Keith CowingOctober 18, 2024October 18, 2024

M dwarf systems offer a unique opportunity to study terrestrial exoplanetary atmospheres due to their smaller size and cooler temperatures. However, due to the extreme conditions these host stars impose, […]

Snapshots of the evolution of planetesimal implantation from a simulation from set 234 starting with 61k planetesimals as the gas giants grow. Terrestrial material is colour coded green-blue and jovian material as yellow-brown. After 0.3 million years the growing Jupiter is scattering planetesimals away, some of which are circularised by gas drag into the inner solar system. After 1 Myr the inner solar system is mixed, and by 5 Myr some embryos can be seen. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Exoplanets, -moons, -comets, Gas Giants, Status Report

Terrestrial Planet Formation During Giant Planet Formation And Giant Planet Migration I: The First 5 Million Years

by Keith CowingOctober 1, 2024October 1, 2024

Terrestrial planet formation (TPF) is a difficult problem that has vexed researchers for decades. Numerical models are only partially successful at reproducing the orbital architecture of the inner planets, but […]

Schematic overview of coupled redox-atmosphere-interior evolution model, PACMAN-P. The model is initialized with a completely molten mantle, and the solidification radius, rs, evolves from the core-mantle boundary to the surface, rp, as the planet cools. At each timestep, we calculate multiphase thermochemical equilibrium between C, H, O, and Fe-bearing species to find the mantle redox state and the partitioning of volatiles between the magma ocean and the atmosphere. Surface climate, Tsurf, is calculated using a radiative-convective model given atmospheric volatile inventories. Under highly reducing conditions created by large H2 envelopes, the reaction of H2 with the silicate magma ocean produces metallic iron, that is either sequestered in the core or remains in the mantle (two endmember assumptions). Atmospheric escape is either XUV-limited or diffusion limited depending on stratospheric composition, and under the former regime we calculate the hydrodynamic drag of O and CO. -- astro-ph.EP

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

The Erosion Of Large Primary Atmospheres Typically Leaves Behind Substantial Secondary Atmospheres On Temperate Rocky Planets

by Keith CowingOctober 1, 2024October 1, 2024

Exoplanet exploration has revealed that many–perhaps most–terrestrial exoplanets formed with substantial H2-rich envelopes, seemingly in contrast to solar system terrestrials, for which there is scant evidence of long-lived primary atmospheres. […]

Zonally and temporally averaged snow fraction for our reference non-impacted model (top left) and at three points in time post-impact for our combined water and heat deposition impact model: 6 months post-impact (top right), 1 year post-impact (bottom left), and 15 years post-impact (bottom right), by which time the impacted models snow fraction has returned to a state clost to that found in our non-impacted reference state. -- astro-ph.EP

Atmospheres, Climate, Weather, Comets and Asteroids, Exoplanets, -moons, -comets, Extinction events, Icy Worlds, Impact events

The Impact of Icy Cometary ‘Impacts’ on Exoplanetary Atmospheres I: Tidally-Locked Terrestrial Exoplanets

by Keith CowingSeptember 18, 2024

Impacts by rocky and icy bodies are thought to have played a key role in shaping the composition of solar system objects, including the Earth’s habitability. Hence, it is likely […]

Two scenarios to produce a high C/O ratio in the inner disk. Schematic cross-sections of the disk around a VLMS in the (A) oxygen depletion and (B) carbon enrichment scenarios. The left sides of each panel illustrate the C/O enrichment process, while the right sides show the resulting state of the disk, corresponding to when we observe it. Colored shading indicates elemental abundances of carbon (orange) and oxygen (blue). The two-color arrows pointing towards the VLMS indicate accretion of material onto the star. The grey arrow indicates transport processes. The region between the two vertical dotted lines indicates the region where the carbon in the solids is released into the gas. The brown, blue, and grey blobs indicate unaffected solids, ice covered solids and carbon depleted solids in the disk respectively. -- astro-ph.EP

Astrochemistry, Astrogeology, Astronomy & Telescopes, Biochemistry & Organic Chemistry, Biosignatures & Paleobiology, Exoplanets, -moons, -comets, Status Report

Abundant Hydrocarbons in the Disk Around a Very-low-mass Star

by Keith CowingJune 21, 2024June 21, 2024

Very low-mass stars (those <0.3 solar masses) host orbiting terrestrial planets more frequently than other types of stars, but the compositions of those planets are largely unknown.

Cartoon of the planetary envelope in different scenarios, each featuring one volatile species (in blue) and one refractory species (in brown). The infalling pebbles are shown on the left side of the envelope. Initially, they consist of a refractory core (brown dot) and an icy volatile layer (blue ring). On the right side, we show the recycling flows (in magenta) and the dust grains (blue dots) that they carry away. The envelope temperature increases overall from A to D. A: Cold envelope in which the volatile sublimation temperature is not reached. B: The volatile species evaporates in the envelope (indicated by the blue arrows), but the recycling flows do not reach deep enough to prevent the accretion of the volatile. Latent heat is absorbed during the evaporation of the volatile ice (indicated by the red arrows). C: The volatile species evaporates in the envelope and the recycling flows transport the vapor back beyond the volatile evaporation front, where the volatile recondenses onto the dust grains. The dust grains covered in ice are then recycled back into the disk. There is no net latent heat absorption due to the recondensation subsequent to the evaporation. D: Same as C, but the envelope is hot enough to vaporize the refractory species, causing the absorption of latent heat in the process. The refractory vapor is not recycled. -- astro-ph.EP

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

A Formation Pathway For Terrestrial Planets With Moderate Water Content Involving Atmospheric-volatile Recycling

by Keith CowingJune 14, 2024June 14, 2024

Of the many recently discovered terrestrial exoplanets, some are expected to harbor moderate water mass fractions of a few percent. The formation pathways that can produce planets with these water […]