Extrasolar Planets


Most Habitable Planets May Lack Dry Land

Most Habitable Planets May Lack Dry Land

When it comes to exploring exoplanets, it may be wise to take a snorkel along. A new study, published in a paper in the journal Monthly Notices of the Royal Astronomical Society, has used a statistical model to predict that most habitable planets may be dominated by oceans spanning over 90% of their surface area.


The O2 A-band in Fluxes and Polarization of Starlight Reflected by Earth-like Exoplanets

The O2 A-band in Fluxes and Polarization of Starlight Reflected by Earth-like Exoplanets

Earth-like, potentially habitable exoplanets are prime targets in the search for extraterrestrial life. Information about their atmosphere and surface can be derived by analyzing light of the parent star reflected by the planet.


NIR-Driven Moist Upper Atmospheres of Synchronously Rotating Temperate Terrestrial Exoplanets

NIR-Driven Moist Upper Atmospheres of Synchronously Rotating Temperate Terrestrial Exoplanets

H2O is a key molecule in characterizing atmospheres of temperate terrestrial planets, and observations of transmission spectra are expected to play a primary role in detecting its signatures in the near future.


Making Terrestrial Planets: High Temperatures, FU Orionis Outbursts, Earth, and Planetary System Architectures

Making Terrestrial Planets: High Temperatures, FU Orionis Outbursts, Earth, and Planetary System Architectures

Current protoplanetary dust coagulation theory does not predict dry silicate planetesimals, in tension with the Earth. While remedies to this predicament have been proposed, they have generally failed numerical studies, or are in tension with the Earth's (low, volatility dependent) volatile and moderately volatile elemental abundances.


A Temperate Rocky Super-Earth Transiting a Nearby Cool Star

A Temperate Rocky Super-Earth Transiting a Nearby Cool Star

M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy [1]. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission spectroscopy when the planets pass in front of these stars [2,3].


Newly Discovered Exoplanet May be Best Candidate in Search for Signs of Life

Newly Discovered Exoplanet May be Best Candidate in Search for Signs of Life

An exoplanet orbiting a red dwarf star 40 light-years from Earth may be the new holder of the title "best place to look for signs of life beyond the Solar System". Using ESO's HARPS instrument at La Silla, and other telescopes around the world, an international team of astronomers discovered a "super-Earth" orbiting in the habitable zone around the faint star LHS 1140.


Updated Masses for the TRAPPIST-1 Planets

Updated Masses for the TRAPPIST-1 Planets

The newly detected TRAPPIST-1 system, with seven low-mass, roughly Earth-sized planets transiting a nearby ultra-cool dwarf, is one of the most important exoplanet discoveries to date.


Initial Reconaissance of a Transiting Rocky Planet in a Nearby M-Dwarf's Habitable Zone

Initial Reconaissance of a Transiting Rocky Planet in a Nearby M-Dwarf's Habitable Zone

We have just discovered a transiting terrestrial planet in a small nearby star's habitable zone. Due to the proximity of the host star and the size of the transit depth, possible constituents for this planet's atmosphere can be detected with the Hubble Space Telescope. Here we propose to use STIS to obtain observations of the host star at Lyman-alpha.


Earth-Sized 'Tatooine' Planets Could Be Habitable

Earth-Sized 'Tatooine' Planets Could Be Habitable

With two suns in its sky, Luke Skywalker's home planet Tatooine in "Star Wars" looks like a parched, sandy desert world.


Kepler-1649b: An Exo-Venus in the Solar Neighborhood

Kepler-1649b: An Exo-Venus in the Solar Neighborhood

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 have Earth-like properties that are amenable to follow-up with both ground- and future space-based surveys, with an ultimate goal of probing their atmospheres to look for signs of life. Venus-like atmospheres will be of particular interest in these surveys.


Atmosphere Around Low-mass Super-Earth Detected

Atmosphere Around Low-mass Super-Earth Detected

Astronomers have detected an atmosphere around the super-Earth GJ 1132b. This marks the first detection of an atmosphere around a low-mass Super-Earth, in terms of radius and mass the most Earth-like planet around which an atmosphere has yet been detected.


Water Transport to Circumprimary Habitable Zones From Icy Planetesimal Disks in Binary Star Systems

Water Transport to Circumprimary Habitable Zones From Icy Planetesimal Disks in Binary Star Systems

So far, more than 130 extrasolar planets have been found in multiple stellar systems. Dynamical simulations show that the outcome of the planetary formation process can lead to different planetary architectures (i.e. location, size, mass, and water content) when the star system is single or double.


An Earth-mass Planet in a 1-AU Orbit Around a Brown Dwarf

An Earth-mass Planet in a 1-AU Orbit Around a Brown Dwarf

We combine Spitzer and ground-based KMTNet microlensing observations to identify and precisely measure an Earth-mass (1.32+0.41−0.28M⊕) planet OGLE-2016-BLG-1195Lb at 1.11+0.13−0.10 AU orbiting a 0.072+0.014−0.010M⊙ ultracool dwarf, likely a brown dwarf.


The Longevity of Water Ice on Ganymedes and Europas Around Migrated Giant Planets

The Longevity of Water Ice on Ganymedes and Europas Around Migrated Giant Planets

The gas giant planets in the Solar System have a retinue of icy moons, and we expect giant exoplanets to have similar satellite systems.


TRAPPIST-1h: A Terrestrial-sized Exoplanet at the Snow Line of TRAPPIST-1

TRAPPIST-1h: A Terrestrial-sized Exoplanet at the Snow Line of TRAPPIST-1

The TRAPPIST-1 system is the first transiting planet system found orbiting an ultra-cool dwarf star. At least seven planets similar to Earth in radius and in mass were previously found to transit this host star.


A Volcanic Hydrogen Habitable Zone

A Volcanic Hydrogen Habitable Zone

The classical habitable zone is the circular region around a star in which liquid water could exist on the surface of a rocky planet. The outer edge of the traditional N2-CO2-H2O habitable zone (HZ) extends out to nearly 1.7 AU in our Solar System, beyond which condensation and scattering by CO2 outstrips its greenhouse capacity.


Triaxial Deformation and Asynchronous Rotation of Rocky Planets in the Habitable Zone of Low-Mass Stars

Triaxial Deformation and Asynchronous Rotation of Rocky Planets in the Habitable Zone of Low-Mass Stars

Rocky planets orbiting M-dwarf stars in the habitable zone tend to be driven to synchronous rotation by tidal dissipation, potentially causing difficulties for maintaining a habitable climate on the planet.


The Equilibrium Temperature of Planets in Elliptical Orbits

The Equilibrium Temperature of Planets in Elliptical Orbits

There exists a positive correlation between orbital eccentricity and the average stellar flux that planets receive from their parent star. Often, though, it is assumed that the average equilibrium temperature would correspondingly increase with eccentricity.


UV Surface Habitability of the TRAPPIST-1 System

UV Surface Habitability of the TRAPPIST-1 System

With the discovery of rocky planets in the temperate habitable zone (HZ) of the close-by cool star TRAPPIST-1 the question of whether such planets could also harbour life arises.


Spitzer Telescope Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star

Spitzer Telescope Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star

NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.



Top stories from April.