Results tagged “Exoplanet”

Exoplanet interior modelling usually makes the assumption that the elemental abundances of a planet are identical to those of its host star. Host stellar abundances are good proxies of planetary abundances, but only for refractory elements.

The relative abundance of deuterium and hydrogen is a potent tracer of planet formation and evolution. Jupiter and Saturn have protosolar D/H ratios, a relic of substantial gas accretion from the nebula, while Neptune and Uranus are enhanced in D by accretion of ices into their envelopes. For terrestrial planets, D/H ratios are used to determine the mechanisms of volatile delivery and subsequent atmosphere loss over the lifetime of the planet.

Exoplanets mass measurements will be a critical next step to assess the habitability of Earth-like planets: a key aspect of the 2020 vision in the previous decadal survey and also central to NASA's strategic priorities.

Mountain ranges, volcanoes, trenches, and craters are common on rocky bodies throughout the Solar System, and we might we expect the same for rocky exoplanets.

Galactic Effects on Habitability

The galactic environment has been suspected to influence planetary habitability in many ways. Very metal-poor regions of the Galaxy, or those largely devoid of atoms more massive than H and He, are thought to be unable to form habitable planets.

Habitability of Exoplanet Waterworlds

We model the evolution of ocean temperature and chemistry for rocky exoplanets with 10-1000 times Earth's H2O but without H2, taking into account C partitioning, high-pressure ice phases, and atmosphere-lithosphere exchange.

Subsurface Exolife

We study the prospects for life on planets with subsurface oceans, and find that a wide range of planets can exist in diverse habitats with relatively thin ice envelopes

As evident from the nearby examples of Proxima Centauri and TRAPPIST-1, Earth-sized planets in the habitable zone of low-mass stars are common. Here, we focus on such planetary systems and argue that their (oceanic) tides could be more prominent due to stronger tidal forces.

Exoplanets and SETI

The discovery of exoplanets has both focused and expanded the search for extraterrestrial intelligence.

In the last decade, over a million stars were monitored to detect transiting planets. Manual interpretation of potential exoplanet candidates is labor intensive and subject to human error, the results of which are difficult to quantify.

We present novel, analytical, equilibrium-chemistry formulae for the abundances of molecules in hot exoplanetary atmospheres that include the carbon, oxygen and nitrogen networks.

A fundamental astrobiological question is whether life arose spontaneously on earth or was transported here from an extrasolar system.

Astronomers have discovered thousands of exoplanets in our galaxy, the Milky Way, using the Kepler satellite and many of them have multiple planets orbiting the host star.

In no other field of astrophysics has the impact of new instrumentation been as substantial as in the domain of exoplanets.

The principle definition of habitability for exoplanets is whether they can sustain liquid water on their surfaces, i.e. that they orbit within the habitable zone.

Having a companion in old age is good for people -- and, it turns out, might extend the chance for life on certain Earth-sized planets in the cosmos as well.

In this paper, we investigate the conditions required for the 3 and 17 Earth mass solid planets in the Kepler-10 system to have formed through collisions and mergers within an initial population of embryos.

Observations of debris disks allow for the study of planetary systems, even where planets have not been detected.

We quantify the effects of refraction in transit transmission spectroscopy on spectral absorption features and on temporal variations that could be used to obtain altitude-dependent spectra for planets orbiting stars of different stellar types.

For planet hunters, this has been a bountiful year. A team lead of astronomers at the SETI Institute and NASA Ames Research Center have used data from NASA's Kepler space telescope to uncover 715 new exoplanets.

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