Results tagged “habitabiility”

Although habitability, defined as the general possibility of hosting life, is expected to occur under a broad range of conditions, the standard scenario to allow for habitable environments is often described through habitable zones (HZs).

Before about 500 million years ago, most probably our planet experienced temporary snowball conditions, with continental and sea ices covering a large fraction of its surface.

The characterization of rocky, Earth-like planets is an important goal for future large ground- and space-based telescopes.

Disequilibria From Dead To Living Worlds

Chemical disequilibrium in exoplanetary atmospheres (detectable with remote spectroscopy) can indicate life.

Planets residing in circumstellar habitable zones (CHZs) offer our best opportunities to test hypotheses of life's potential pervasiveness and complexity.

Correct estimates of stellar extreme ultraviolet (EUV; 100 - 1170 Å) flux are important for studying the photochemistry and stability of exoplanet atmospheres, as EUV radiation ionizes hydrogen and contributes to the heating, expansion, and potential escape of a planet's upper atmosphere.

Investigating the atmospheres of rocky exoplanets is key to performing comparative planetology between such worlds and the terrestrial planets that reside in the inner Solar System.

In the past decade, observations from space and ground have found H2O to be the most abundant molecular species, after hydrogen, in the atmospheres of hot, gaseous, extrasolar planets. Being the main molecular carrier of oxygen, H2O is a tracer of the origin and the evolution mechanisms of planets.

Astronomical calculations reveal the solar system's dynamical evolution, including its chaoticity, and represent the backbone of cyclostratigraphy and astrochronology.

This paper reviews habitability conditions for a terrestrial planet from the point of view of geosciences. It addresses how interactions between the interior of a planet or a moon and its atmosphere and surface (including hydrosphere and biosphere) can affect habitability of the celestial body.

The frequency of Earth-size planets in the habitable zone of Sun-like stars, hereafter η⊕, is a key parameter to evaluate the yield of nearby Earth analogues that can be detected and characterized by future missions.

A new study provides the most accurate estimate of the frequency that planets that are similar to Earth in size and in distance from their host star occur around stars similar to our Sun.

High-energy radiation caused by exoplanetary space weather events from planet-hosting stars can play a crucial role in conditions promoting or destroying habitability in addition to the conventional factors.

The Gaia hypothesis postulates that life regulates its environment to be favorable for its own survival. Most planets experience numerous perturbations throughout their lifetimes such as asteroid impacts, volcanism, and the evolution of a star's luminosity

Exploring diverse planetary atmospheres requires modeling tools that are both accurate and flexible.

An exoplanet's habitability will depend strongly on the presence of liquid water. Flux and/or polarization measurements of starlight that is reflected by exoplanets could help to identify exo-oceans.

It is now recognized that energetic stellar photon and particle radiation evaporates and erodes planetary atmospheres and controls upper atmospheric chemistry.

The habitability of a planet depends on various factors, such as delivery of water during the formation, the co-evolution of the interior and the atmosphere, as well as the stellar irradiation which changes in time.

The circumstellar habitable zone and its various refinements serves as a useful entry point for discussing the potential for a planet to generate and sustain life.

Better to Dry a Rocky Planet Before Use

Earth's solid surface and clement climate may be in part due to a massive star in the birth environment of the Sun. Without its radioactive elements injected into the early solar system, our home planet could be a hostile ocean world covered in global ice sheets.

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