The recent discovery of three Earth-sized, potentially habitable planets around a nearby cool star, TRAPPIST-1, has provided three key targets for the upcoming James Webb Space Telescope (JWST).
We present a survey on binary star systems with stellar separations less than 100 astronomical units.
An analysis of the currently known exoplanets in the habitable zones (HZs) of their host stars is of interest in both the wake of the NASA Kepler mission and with prospects for expanding the known planet population through future ground- and space-based projects.
Solar coronal mass ejections (CMEs) produce adverse space weather effects at Earth. Planets in the close habitable zone of magnetically active M dwarfs may experience more extreme space weather than at Earth, including frequent CME impacts leading to atmospheric erosion and leaving the surface exposed to extreme flare activity.
Scientists from Princeton University and NASA have confirmed that 1,284 objects observed outside Earth's solar system by NASA's Kepler spacecraft are indeed planets.
Next-generation space telescopes will observe the atmospheres of rocky planets orbiting nearby M-dwarfs. Understanding these observations will require well-developed theory in addition to numerical simulations.
Many observed giant planets lie on eccentric orbits. Such orbits could be the result of strong scatterings with other giant planets. The same dynamical instability that produces giant planet scatterings can also alter the orbits of terrestrial planets.
Ultracool dwarfs (UCD) encompass the population of extremely low mass stars (later than M6-type) and brown dwarfs.
Astronomers using the TRAPPIST telescope at ESO's La Silla Observatory have discovered three planets orbiting an ultracool dwarf star just 40 light-years from Earth.
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.
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?
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.
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.
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).
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.
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.
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.
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.
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.
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.