Related papers: Direct Imaging Search for Extrasolar Planets in th…

The orbital parameters of binaries at intermediate periods ($10^2$--$10^3$ d) are difficult to measure with conventional methods and are very incomplete. We have undertaken a new survey, applying our pulsation timing method to {\it Kepler}…

Direct imaging (DI) campaigns are uniquely suited to probing the outer regions around young stars and looking for giant exoplanet and brown dwarf companions, hence providing key complementary information to radial velocity (RV) and transit…

Precise mass constraints are vital for the characterisation of brown dwarfs and exoplanets. Here we present how the combination of data obtained by Gaia and GRAVITY can help enlarge the sample of substellar companions with measured…

Eps Ind A is one of the nearest sun-like stars, located only 3.6 pc away. It is known to host a binary brown dwarf companion, Eps Ind Ba/Bb, at a large projected separation of 6.7", but radial velocity measurements imply that an additional,…

We conducted a search for brown dwarfs (BDs) and very low mass (VLM) stars in the 625 Myr-old Hyades cluster in order to derive the cluster's mass function across the stellar-substellar boundary. We performed a deep (I=23, z=22.5)…

A large number of direct imaging surveys for exoplanets have been performed in recent years, yielding the first directly imaged planets and providing constraints on the prevalence and distribution of wide planetary systems. However, like…

Many transiting planet host stars lack high resolution imaging and thus close stellar sources can be missed. Those unknown stars potentially bias the derivation of the planetary and stellar parameters from the transit light curve, no matter…

We present Spitzer IRAC photometry of white dwarf remnants of 14 stars with M = 3-5 Msol. We do not detect mid-infrared excess around any of our targets. By demanding a 3 sigma photometric excess at 4.5 micron for unresolved companions, we…

We present preliminary limits on the presence of planets around white dwarf stars using the IRAC photometer on the Spitzer space telescope. Planets emit strongly in the mid-infrared which allows their presence to be detected as an excess at…

Extremely low-mass white dwarfs (ELM WDs) are helium-core white dwarfs with masses less than 0.3 $M_{\odot}$. Short-period ELM WD binaries that exhibit ellipsoidal variations may harbor heavier companions, either massive white dwarfs or…

We present the analysis of a 38.4 ks and a 23.6 ks observation of the core of the Pleiades open cluster. The Advanced CCD Imaging Spectrometer on board the Chandra X-ray Observatory detected 99 X-ray sources in a 17'X17' region, including…

We present the results of an adaptive optics survey for faint companions among Galactic O-type star systems (V < 8) using the Advanced Electro-Optical System (AEOS) 3.6-meter telescope on Haleakala. We surveyed these O star systems in…

We report initial results of a large radial velocity survey of K dwarfs up to a distance of 50 pc from the Solar System, to look for stellar, brown dwarf, and jovian planets using radial velocities from the CHIRON spectrograph on the…

The proposed global astrometry mission {\it GAIA}, recently recommended within the context of ESA's Horizon 2000 Plus long-term scientific program, appears capable of surveying the solar neighborhood within $\sim$ 200 pc for the astrometric…

In this article we present the case of HD 41004 AB, a system composed of a K0V star and a 3.7-magnitude fainter M-dwarf companion separated by only 0.5 arcsec. An analysis of CORALIE radial-velocity measurements has revealed a variation…

We present the performances of a radial velocity measurement method that we developed for A-F type stars. These perfomances are evaluated through an extensive set of simulations, together with actual radial velocity observations of such…

Of the approximately 350 extrasolar planets currently known, of order 10% orbit evolved stars with radii R >~ 2.5 R_sun. These planets are of particular interest because they tend to orbit more massive hosts, and have been subjected to…

[abridged] We carry out numerical simulations to gauge the Gaia potential for precision astrometry of exoplanets orbiting a sample of known dM stars within 30 pc from the Sun. (1) It will be possible to accurately determine orbits and…

51 Eridani b is an exoplanet around a young (20 Myr) nearby (29.4 pc) F0-type star, recently discovered by direct imaging. Being only 0.5" away from its host star it is well suited for spectroscopic analysis using integral field…

Up to now, most planet search projects have concentrated on F to K stars. In order to considerably widen the view, we have stated a survey for planets of old, nearby brown dwarfs and very low mass stars. Using UVES, we have observed 26…