Results tagged “exoplanet”

Thousands of exoplanets have been detected to date, and with future planned missions this tally will increase.

The most abundant stars in the Galaxy, M dwarfs, are very commonly hosts to diverse systems of low-mass planets. Their abundancy implies that the general occurrence rate of planets is dominated by their occurrence rate around such M dwarfs.

We present the result of calculations to optimize the search for molecular oxygen (O2) in Earth analogs transiting around nearby, low-mass stars using ground-based, high-resolution, Doppler shift techniques.

Transmission spectroscopy is an important technique to probe the atmospheres of exoplanets.

Here we describe a story behind the discovery of Kepler-46, which was the first exoplanetary system detected and characterized from a method known as the transit timing variations (TTVs).

Over the past three decades instruments on the ground and in space have discovered thousands of planets outside the solar system.

The expected yield of potentially Earth-like planets is a useful metric for designing future exoplanet-imaging missions.

Rocky, Earth-like planets orbiting our closest stars could host life, according to a new study that raises the excitement about exoplanets.

We modeled the transit signatures in the Lya line of a putative Earth-sized planet orbiting in the HZ of the M dwarf GJ436.

Topography of (exo)planets

Current technology is not able to map the topography of rocky exoplanets, simply because the objects are too faint and far away to resolve them. Nevertheless, indirect effect of topography should be soon observable thanks to photometry techniques, and the possibility of detecting specular reflections.

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.

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