Related papers: Kinematics and binaries in young stellar aggregate…
Between 1996 and 2003 we have obtained 226 high resolution spectra of 16 stars in the field of the young open cluster NGC 6913, to the aim of constraining its main properties and study its internal kinematics. Twelve of the program stars…
The frequency of low-mass pre-main sequence binary systems is significantly lower in the Trapezium Cluster than in Taurus-Auriga. We investigate if this difference can be explained through stellar encounters in dense clusters. To this…
The solar galactic neighbourhood contains a number of young co-moving associations of stars (so-called `young moving groups') with ages of ~10--150 Myr, which are prime targets for a range of scientific studies, including direct imaging…
We present a kinematic study of the Orion Nebula Cluster based upon radial velocities measured by multi-fiber echelle spectroscopy at the 6.5 meter MMT and Magellan telescopes. Velocities are reported for 1613 stars, with multi-epoch data…
This paper describes a high-resolution, infrared spectroscopic survey of young, low-mass stars designed to identify and characterize pre-main-sequence spectroscopic binaries. This is the first large infrared radial velocity survey of very…
We present new MMT/Hectochelle spectroscopic measurements for 257 stars observed along the line of sight to the ultra-faint dwarf galaxy Triangulum II. Combining with results from previous Keck/DEIMOS spectroscopy, we obtain a sample that…
We present the first multi-epoch radial velocity study of embedded young massive stars using near-infrared spectra obtained with ISAAC mounted at the ESO Very Large Telescope, with the aim to detect massive binaries. Our 16 targets are…
We study the dynamical interaction in which the two single runaway stars AE Aurigae and mu Columbae and the binary iota Orionis acquired their unusually high space velocity. The two single runaways move in almost opposite directions with a…
Multiplicity among massive stars represents a major uncertainty in stellar evolution theory, because the extra physical processes that it introduces significantly impacts each star's structure. While multiplicity of O-type stars is fairly…
We use N-body integration to follow the evolution of clusters of 200 binary systems with different initial half mass radii $R_{0.5}$. We also simulate single-star clusters. All clusters evolve according to the same $n(t)$ curve, where…
Significant progress has been made toward understanding the formation of massive ($M > 8~$M$_{\odot}$) binaries in close orbits. For example, the detection of a very low velocity dispersion among the massive stars in the young region M17…
As part of our search for new low-mass members of nearby young moving groups (YMG), we discovered three low-mass, spectroscopic binaries, two of which are not kinematically associated with any known YMG. Using high-resolution optical…
We present the first scientific images obtained with a deformable secondary mirror adaptive optics system. We utilized the 6.5m MMT AO system to produce high-resolution (FWHM=0.07'') near infrared (1.6 um) images of the young (~1 Myr) Orion…
Transition disks (TDs) are intermediate stage circumstellar disks characterized by an inner gap within the disk structure. To test whether these gaps may have been formed by closely orbiting, previously undetected stellar companions, we…
We have selected archival observational data for several O and B trapezia in the Milky Way. For each of the main components of the trapezia we obtained transverse velocities from the historical separation data. With this information, and…
We derive single-epoch radial velocities for a sample of 56 B-type stars members of the subgroups Upper Scorpius, Upper Centaurus Lupus and Lower Centaurus Crux of the nearby Sco-Cen OB association. The radial velocity measurements were…
A search for spectroscopic binaries on the main sequence of the nearby globular cluster M4 has been undertaken with Argus, the multi-object spectrograph on the CTIO 4.0m telescope. A pair of radial velocities (median precision $\simeq$ 2…
Kinematics of 237 Chromospherically Active Binaries (CAB) were studied. The sample is heterogeneous with different orbits and physically different components from F to M spectral type main sequence stars to G and K giants and super giants.…
We report on new radial velocity measurements of massive stars that are either suspected binaries or lacking prior observations. This is part of a survey to identify and characterize spectroscopic binaries among O-type stars with the goal…
AIMS We plan to identify the members of the Bochum7 association by performing simultaneous astrometric and spectrophotometric analyses, and estimate its distance and evolutionary stage. METHODS. We used our own visual spectroscopic and UBV…