Related papers: Alpha Centauri: Disc Dynamics, Planet Stability, D…

At a distance of 1.8 parsecs, Barnard's star (Gl 699) is a red dwarf with the largest apparent motion of any known stellar object. It is the closest single star to the Sun, second only to the alpha Centauri triple stellar system. Barnard's…

The Gamma Cephei planetary system is one of the most interesting systems due to several reasons: 1.) it is the first planet candidate detected by precise radial velocity (RV) measurements that was discussed in the literature (Campbell et…

The Orion BN/KL complex is the nearest site of ongoing high-mass star formation. Recent proper motion observations provide convincing evidence of a recent (about 500 years ago) dynamical interaction between two massive young stellar objects…

It has been suggested that the long-lived residual radial velocity variations observed in the precision radial velocity measurements of the primary of Gamma Cephei (HR8974, HD222404, HIP116727) are likely due to a Jupiter-like planet around…

In the last years several exoplanets have been discovered that orbit one component of a compact binary system (separation < 50 astronomical units), the probably best-known case is gamma-Cephei. So far, all attempts to explain the in-situ…

The jet-counterjet system of the closest radio-loud active galaxy Centaurus A (Cen A) can be studied with Very Long Baseline Interferometry (VLBI) on unprecedented small linear scales of ~0.018pc. These high-resolution observations provide…

The field of exoplanetary science has seen discovery rates increase dramatically over recent years, due largely to the data from the Kepler mission. Even so, individual discoveries of planets orbiting nearby stars are very important for…

We develop a rapid algorithm for the evolution of stable, circular, circumbinary discs suitable for parameter estimation and population synthesis modelling. Our model includes disc mass and angular momentum changes, accretion on to the…

The recent discovery of potentially habitable exoplanets around Proxima Centauri and TRAPPIST-1 has attracted much attention due to their potential for hosting life. We delineate a simple model that accurately describes the evolution of…

We have found that Proxima Centauri, the star closest to our Sun, will pass close to a pair of faint background stars in the next few years. Using Hubble Space Telescope (HST) images obtained in 2012 October, we determine that the passage…

The observational study of stars in the sub-millimetre regime has only rather recently begun and was made possible mainly by the Atacama Large Millimeter/submillimeter Array (ALMA). The emission mechanisms of this radiation from normal MS…

The presence of planets in binary systems poses interesting problems for planet formation theories, both in cases where planets must have formed in very compact discs around the individual stars and where they are located near the edge of…

At radio wavelengths, solar-type stars emit thermal free-free and gyroresonance, gyrosynchrotron, and impulsive coherent emission. Thermal free-free emission originates at layers where the optical depth is close to unit, while high…

Dynamical mass estimates down to the planet-mass regime can help to understand planet formation. We present Atacama Large Millimeter/submillimeter Array (ALMA) 1.3 mm observations of FW Tau C, a proposed ~10 $M_{\rm Jup}$ planet-mass…

At least 10-15% of nearby sun-like stars have known Jupiter-mass planets. In contrast, very few planets are found in mature open and globular clusters such as the Hyades and 47 Tuc. We explore here the possibility that this dichotomy is due…

With more than 260 extrasolar planetary systems discovered to-date, the search for habitable planets has found new grounds. Unlike our solar system, the stars of many of these planets are hosts to eccentric or close-in giant bodies. Several…

Over 30 planetary systems have been discovered to reside in binary stars. For small separations gravitational perturbation of the secondary star has a strong influence on the planet formation process. It truncates the protoplanetary disk,…

Recent radial velocity and transit data discovered $\sim 100$ planets in binary or triple stellar systems out of the entire population of a few thousand known planets. Stellar companions are expected to strongly influence both the formation…

The discovery of a planet orbiting around Proxima Centauri, the closest star to the Sun, opens new avenues for the remote observations of the atmosphere and surface of an exoplanet, Proxima b. To date, three-dimensional (3D) General…

The stellar dynamics of Omega Centauri are inferred from the radial velocities of 469 stars measured with CORAVEL (Mayor et al. 1997). Rather than fit the data to a family of models, we generate estimates of all dynamical functions…