Related papers: TRAPPIST-1 d: Exo-Venus, Exo-Earth or Exo-Dead?
The recent detection of Earth-sized planets in the habitable zone of Proxima Centauri, Trappist-1 and many other nearby M-type stars has led to speculations, whether liquid water and life actually exist on these planets. To a large extent,…
Earth is the only planet known to harbor life and, as a result, the search for habitable and inhabited planets beyond the Solar System commonly focuses on analogs to our planet. However, Earth's atmosphere and surface environment have…
As the closest Earth-like exoplanet within the habitable zone of the M-dwarf star TRAPPIST-1, TRAPPIST-1e exhibits a magnetic field topology that is dependent on space weather conditions. Variations in these conditions influence its…
Why are the terrestrial planets so different? Venus should be the most Earth-like of all our planetary neighbours. Its size, bulk composition and distance from the Sun are very similar to those of the Earth. Its original atmosphere was…
Venus is Earth's sister planet, with similar mass and density but an uninhabitably hot surface, an atmosphere with a water activity 50-100 times lower than anywhere on Earths' surface, and clouds believed to be made of concentrated sulfuric…
With seven temperate Earth-sized planets revolving around an ultracool red dwarf, the nearby TRAPPIST-1 system offers a unique opportunity to verify models of exoplanet composition, differentiation, and interior structure. In particular,…
The Kepler mission has revealed that Earth-sized planets are common, and dozens have been discovered to orbit in or near their host star's habitable zone. A major focus in astronomy is to determine which of these exoplanets are likely to…
The dominant paradigm in assigning "habitability"' to terrestrial planets is to define a circumstellar habitable zone: the locus of orbital radii in which the planet is neither too hot nor too cold for life as we know it. One dimensional…
The TRAPPIST-1 system is comprised of seven Earth-sized rocky planets in small orbits around a Jupiter-sized ultracool dwarf star 12 parsec away. These planets cover an irradiation range similar to the range of the inner solar system. Three…
The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbour liquid water on their surfaces. UV observations are essential to measure their high-energy irradiation, and to search for…
As the discovery of exoplanets progresses at a rapid pace, the large number of known planets provides a pathway to assess the stellar and planetary properties that govern the climate evolution of terrestrial planets. Of particular interest…
As the characterization of exoplanet atmospheres proceeds, providing insights into atmospheric chemistry and composition, a key question is how much deeper into the planet we might be able to see from its atmospheric properties alone. For…
This paper presents the first structured evaluation of Solar System bodies hypothetically relocated to Earth orbit (1 AU) to assess their potential as alternative habitats. Using comparative criteria, planetary size and gravity, atmospheric…
Radial velocity surveys are now able to detect terrestrial planets at habitable distance from M-type stars. Recently, two planets with minimum masses below 10 Earth masses were reported in a triple system around the M-type star Gliese 581.…
We use the TRAPPIST-1 system as a model observation of Earth-like planets. The densities of these planets being 1-10% less than the Earth suggest that the outer planets may host significant hydrospheres. We explore the uncertainty in water…
The success of the Transiting Exoplanet Survey Satellite (TESS) mission has led to the discovery of an abundance of Venus Zone (VZ) terrestrial planets that orbit relatively bright host stars. Atmospheric observations of these planets play…
JWST observations of the 7-planet TRAPPIST-1 system will provide an excellent opportunity to test outcomes of stellar-driven evolution of terrestrial planetary atmospheres, including atmospheric escape, ocean loss and abiotic oxygen…
The recently discovered exoplanet Gl581d is extremely close to the outer edge of its system's habitable zone, which has led to much speculation on its possible climate. We have performed a range of simulations to assess whether, given…
What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance to optimize future telescopic…
Venus and Earth provide astonishingly different views of the evolution of a rocky planet, raising the question of why these two rocky worlds evolved so differently. The recently discovered transiting Super-Earth LP 890-9c (TOI-4306c,…