Earth-like Planet Archives - Page 8 of 8 - Astrobiology

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 […]

Boundaries of the Habitable Zone under various climate and atmospheric models as a function of radiative flux received from the host star, relative to Earth. Dashed lines represent the extended boundaries due to subglacial liquid water suggested in this work: blue for the inner HZ boundary (nightside ice evaporates due to heat transport, the percentage marks the global transport parameter f) and violet for the outer one (Martian polar lakes). Solid green lines and green shading denote the conservative HZ boundaries: inner one (moist greenhouse) and outer one (maximum CO2 greenhouse), calculated using the 1-D climate model. Also marked is the recent Venus boundary (dashed green line). The orange curve marks the tidal locking radius. Circles denote the terrestrial planets in the solar system and a few Earth-sized exoplanets orbiting M-dwarf stars. -- Hebrew University of Jerusalem

Biogeochemical Cycles & Geobiology, Exoplanets, -moons, -comets, Habitable Zones, Icy Worlds, Press Release, Water/Hycean Worlds & Oceanography

Extended Habitability Of Exoplanets Due To Subglacial Water

by Keith CowingNovember 10, 2023November 10, 2023

Professor Amri Wandel, from Hebrew University of Jerusalem, has unveiled research that promises to redefine our comprehension of habitable exoplanets. In a recent study published in the Astronomical Journal, Professor […]

Comparable monthly insolation patterns for Cases 1–4 at given snapshots in their eccentricity evolution. We do not include snapshots of the higher eccentricity values attained in Case 4. Insolation bar in the lower right goes from zero to 341 W m−2 . Note that we plot Case 4 in the first column and Cases 1–3 in columns 2–4 to make comparisons between Cases 4 and 1 easier. -- astro-ph.EP

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Gravitational Biology, Status Report

Exploring Climate With Obliquity In A Variable-eccentricity Earth-like World

by Keith CowingNovember 8, 2023

Exploring planetary systems similar to our solar system can provide a means to explore a large range of possibly temperate climates on Earth-like worlds.

Mass-radius diagram showing confirmed planets with mass uncertainties < 20% in grey circles, with TOI-544 b shown as the black circle. Left: the coloured tracks show different potential planet compositions from Zeng et al. (2019), assuming a planetary equilibrium temperature of 1000 K. The dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass, the solid lines show water world compositions with varying water mass fractions, the dotted lines show rocky and Earth-like rocky compositions. TOI-544 b is closest to the tracks with 100% H2O and 50% H2O with 50% rock. Right: the same as the left panel but the the dashed lines show compositions of an Earth-like rocky core surrounded by a layer of H-He in varying percentages by mass from Lopez & Fortney (2014) using the models for a 10Gyr planet, with solar metalicity and flux of 10F⊕, the solid lines show compositions from Aguichine et al. (2021) of irradiated ocean worlds with varying water mass fractions, and the dotted lines show the same rocky and Earth-like rocky compositions from Zeng et al. (2019). TOI-544 b is closest to models with either 30% water mass fraction, or a rocky core with a Hydrogen envelope of between 0.5 - 1%. The data is downloaded from the NASA Exoplanet Archive. -- astro-ph.EP

Astronomy & Telescopes, Atmospheres, Climate, Weather, Biosignatures & Paleobiology, Exploration Gear & Tech, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Status Report, Water/Hycean Worlds & Oceanography

TOI-544 b: A Potential Water-world Inside The Radius Valley In A Two-planet System

by Keith CowingOctober 24, 2023October 24, 2023

We report on the precise radial velocity follow-up of TOI-544 (HD 290498), a bright K star (V=10.8), which hosts a small transiting planet recently discovered by the Transiting Exoplanet Survey […]

Habitable Zones, Press Release

Atmospheres and UV Environments of Earth-like Planets Throughout Post-Main Sequence Evolution

by Keith CowingApril 24, 2019

During the post-main sequence phase of stellar evolution the orbital distance of the habitable zone, which allows for liquid surface water on terrestrial planets, moves out past the system’s original […]

KOI-314c HSCFA/David Aguilar

Atmospheres, Climate, Weather, Exoplanets, -moons, -comets, Press Release

Newfound Planet Is Earth-mass But Gassy

by Keith CowingJanuary 6, 2014September 18, 2025

An international team of astronomers has discovered the first Earth-mass planet that transits, or crosses in front of, its host star. KOI-314c is the lightest planet to have both its […]