Extrasolar Planets


Effects of Mg/Si on Exoplanetary Refractory Oxygen Budget

Effects of Mg/Si on Exoplanetary Refractory Oxygen Budget

Solar photospheric abundances of refractory elements mirror the Earth's to within ~10 mol% when normalized to the dominant terrestrial planet-forming elements Mg, Si and Fe. This allows for the adoption of Solar composition as an order-of-magnitude proxy for Earth's.


Hiding in the Sunshine: The Search for Other Earths

Hiding in the Sunshine: The Search for Other Earths

We humans might not be the only ones to ponder our place in the universe. If intelligent aliens do roam the cosmos, they too might ask a question that has gripped humans for centuries: Are we alone?


Giant Planets in the Habitable Zone

Giant Planets in the Habitable Zone

We report the discovery of three new substellar companions to solar-type stars, HD191806, HD214823, and HD221585, based on radial velocity measurements obtained at the Haute-Provence Observatory.


Herschel Detects Oxygen in the beta Pictoris Debris Disk

Herschel Detects Oxygen in the beta Pictoris Debris Disk

The young star beta Pictoris is well known for its dusty debris disk, produced through the grinding down by collisions of planetesimals, kilometre-sized bodies in orbit around the star.


Habitability of Planets on Eccentric Orbits: Limits of the Mean Flux Approximation

Habitability of Planets on Eccentric Orbits: Limits of the Mean Flux Approximation

Contrary to Earth, which has a small orbital eccentricity, some exoplanets discovered in the insolation habitable zone (HZ) have high orbital eccentricities (e.g., up to an eccentricity of ∼0.97 for HD~20782~b).


Exoplanetary Atmospheres: Chemistry, Formation Conditions, and Habitability

Exoplanetary Atmospheres: Chemistry, Formation Conditions, and Habitability

Characterizing the atmospheres of extrasolar planets is the new frontier in exoplanetary science. The last two decades of exoplanet discoveries have revealed that exoplanets are very common and extremely diverse in their orbital and bulk properties.


The Imprecise Search for Habitability

The Imprecise Search for Habitability

As planets are being discovered around other stars by the thousands, several scientific disciplines that traditionally exist in parallel are converging, including astronomy, planetary science, and biochemistry.


The Fine Structure Constant and Habitable Planets

The Fine Structure Constant and Habitable Planets

We use the existence of habitable planets to impose anthropic requirements on the fine structure constant, α. To this effect, we present two considerations that restrict its value to be very near the one observed.


Impact of Stellar Rotation on Detectability of Habitable Planets Around M Dwarfs

Impact of Stellar Rotation on Detectability of Habitable Planets Around M Dwarfs

Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years.


Long-Term Stability of Planets in the α Centauri System

Long-Term Stability of Planets in the α Centauri System

We evaluate the extent of the regions within the α Centauri AB star system where small planets are able to orbit for billion-year timescales, and we calculate the positions on the sky plane where planets on stable orbits about either stellar component may appear.


An Earth-Like Planet in the GJ 832 System

An Earth-Like Planet in the GJ 832 System

Stability of planetary orbits around GJ 832 star system, which contains inner (GJ 832c) and outer (GJ 832b) planets, is investigated numerically and the detailed phase-space analysis are performed.


Reflected Light From Giant Planets in Habitable Zones

Reflected Light From Giant Planets in Habitable Zones

The direct detection of reflected light from exoplanets is an excellent probe for the characterization of their atmospheres.


Ocean Circulation on Distant Planets

Ocean Circulation on Distant Planets

The salt levels of oceans on distant Earth-like planets could have a major effect on their climates - according to new research from the Centre for Ocean and Atmospheric Sciences at the University of East Anglia.


SET-E: The Search for Extraterrestrial Environmentalism

SET-E: The Search for Extraterrestrial Environmentalism

There is currently no evidence for life on any known exoplanet. Here, we propose a form of "galactic anthropology" to detect not only the existence of life on transiting exoplanets, but also the existence of environmentalism movements.


Galactic Cosmic Rays on Extrasolar Earth-like Planets: Atmospheric Implications

Galactic Cosmic Rays on Extrasolar Earth-like Planets: Atmospheric Implications

Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields. As described in the companion article (Paper I), a weak magnetic field results in a high flux of galactic cosmic rays to the top of the planetary atmosphere.


Analytical Models of Exoplanetary Atmospheres: Gaseous C-H-O-N Chemistry with 9 Molecules

Analytical Models of Exoplanetary Atmospheres: Gaseous C-H-O-N Chemistry with 9 Molecules

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


Magnetic Field Was Critical for Life on the Early Earth

Magnetic Field Was Critical for Life on the Early Earth

Nearly four billion years ago, life arose on Earth. Life appeared because our planet had a rocky surface, liquid water, and a blanketing atmosphere. But life thrived thanks to another necessary ingredient: the presence of a protective magnetic field.


The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f

The Effect of Orbital Configuration on the Possible Climates and Habitability of Kepler-62f

As lower-mass stars often host multiple rocky planets, gravitational interactions among planets can have significant effects on climate and habitability over long timescales.


Influence of Water Content in Protoplanetary Discs on Planet Migration and Formation

Influence of Water Content in Protoplanetary Discs on Planet Migration and Formation

The temperature and density profiles of protoplanetary discs depend crucially on the mass fraction of micrometre-sized dust grains and on their chemical composition.


Telling Twins Apart: Exo-Earths and Venuses With Transit Spectroscopy

Telling Twins Apart: Exo-Earths and Venuses With Transit Spectroscopy

The planned launch of the James Webb Space Telescope in 2018 will herald a new era of exoplanet spectroscopy. JWST will be the first telescope sensitive enough to potentially characterize terrestrial planets from their transmission spectra.



Top stories from April.