Related papers: Modelling a Transiting Circumbinary Disc in the HD…
In a multi-wavelength study of thermal emission and scattered light images we analyse the dust properties and structure of the debris disc around the A1-type main sequence star 49~Cet. As a basis for this study, we present new scattered…
(Abridged) A numerical model of a circumstellar debris disk is developed and applied to observations of the circumstellar dust orbiting beta Pictoris. The model accounts for the rates at which dust is produced by collisions among unseen…
Four gamma-ray binaries, namely PSR B1259-63, HESS J0632+057, HD 215227 and LS I +61 303, contain compact objects orbiting around massive Be stars. The nature of the compact object is only known in the case of PSR B1259-63, but the other…
In a recent study, Lee et al. presented new photometric follow-up timing observations of the semi-detached binary system SZ Herculis and proposed the existence of two hierarchical cirumbinary companions. Based on the light-travel time…
Circumstellar disks around stars older than 10 Myr are expected to be gas-poor. There are, however, two examples of old (30-40 Myr) debris-like disks containing a detectable amount of cold CO gas. Here we present ALMA and Herschel Space…
We present the results of two-fluid hydrodynamical simulations of circumbinary discs consisting of gas and dust, with and without embedded planets, to examine the influence of the dust on the structure of the tidally truncated inner cavity…
High-accuracy multicolor light curves of the binary system HD 189733, which contains an exoplanet, are analyzed. We have determined the radii of the star and the planet in the binary system, as well as the orbital inclination. The…
We have observed the protoplanetary disk of the well-known young Herbig star HD 142527 using ZIMPOL Polarimetric Differential Imaging with the VBB (Very Broad Band, ~600-900nm) filter. We obtained two datasets in May 2015 and March 2016.…
Birth environments of young stars have strong imprints on the star itself and their surroundings. We present a detailed analysis of the wealthy circumstellar environment around the young Herbig Ae/Be star TCrA. Our aim is to understand the…
We numerically study the tidal instability of accretion discs in close binary systems using a two-dimensional SPH code. We find that the precession rate of tidally unstable, eccentric discs does not only depend upon the binary mass ratio q.…
In a previous work (Pichardo et al. 2005), we studied stable configurations for circumstellar discs in eccentric binary systems. We searched for "invariant loops": closed curves (analogous to stable periodic orbits in time-independent…
ALMA has revealed that the millimetre dust structures of protoplanetary discs are extremely diverse. It has been proposed that the strength of H$_2$O emission in the inner disc particularly depends on the influx of icy pebbles from the…
We present Hubble Space Telescope observations of six binary transneptunian systems: 2000 QL251, 2003 TJ58, 2001 XR254, 1999 OJ4, (134860) 2000 OJ67, and 2004 PB108. The mutual orbits of these systems are found to have periods ranging from…
Many questions remain regarding the properties of disks around massive prototstars. Here we present the observations of a high mass protostellar object including an elongated dust continuum structure perpendicular to the outflow.…
We aim at constraining evolutionary models at low mass and young ages by identifying interesting transiting system members of the nearest OB association to the Sun, Upper Scorpius, targeted by the Kepler mission. We produced light curves…
HD 135344B is an accreting (pre-) transition disk that displays the emission of warm CO extending tens of AU inside its 30 AU dust cavity. We used the dust radiative transfer code MCFOST and the thermochemical code ProDiMo to derive the…
We present a spectroscopic and photometric study of the Double Period Variable HD170582. Based on the study of the ASAS V-band light curve we determine an improved orbital period of 16.87177 $\pm$ 0.02084 days and a long period of 587 days.…
Context. Kepler observations have revealed a class of short period exoplanets, of which Kepler-1520 b is the prototype, which have comet-like dust tails thought to be the result of small, rocky planets losing mass. The shape and…
Observed IR excesses indicate that protoplanetary discs evolve slowly for the majority of their lifetime before losing their near- and mid-IR excesses on short timescales. Photoevaporation models can explain this "two-timescale" nature of…
We study the mutual evolution of the orbital properties of high mass ratio, circular, co-planar binaries and their surrounding discs, using 3D Smoothed Particle Hydrodynamics simulations. We investigate the evolution of binary and disc…