Related papers: Multiple Star Systems in the Orion Nebula
We report discovery and spectroscopic follow-up of 21 astrometric binaries containing solar-type stars and dark companions with masses near 1.4 $M_{\odot}$. The simplest interpretation is that the companions are dormant neutron stars (NSs),…
We conducted a deep survey of resolved sub-systems among wide binaries with solar-type components within 67 pc from the Sun. Images of 61 stars in the K and H bands were obtained with the NICI adaptive-optics instrument on the 8-m…
The understanding of the accretion process has a central role in the understanding of star and planet formation. We aim to test how accretion variability influences previous correlation analyses of the relation between X-ray activity and…
High precision radial velocity observations of the solar-type star 16 Cygni B taken at McDonald Observatory and at Lick Observatory, have each independently discovered periodic radial-velocity variations indicating the presence of a…
Almost half of the stellar systems in the solar neighborhood are made up of multiple stars. In multiple-star systems, planet formation is under the dynamical influence of stellar companions, and the planet occurrence rate is expected to be…
We describe an astrometric and spectroscopic campaign to confirm the youth and association of a complete sample of candidate wide companions in Taurus and Upper Sco. Our survey found fifteen new binary systems (3 in Taurus and 12 in Upper…
We report the initial results of a large-scale optical-near infrared survey to extend the known young population of the entire Orion star-forming region down to the substellar domain. Using deep optical I-band photometry and data from the…
Recently, three stellar sequences separated in age by about 1 Myr were discovered in the Orion Nebula Cluster (ONC; Beccari et al. 2017). Kroupa et al. (2018) suggest that such small dense subpopulations eject all their OB stars via the…
The spatial morphology and dynamical status of a young, still-forming stellar cluster provide valuable clues on the conditions during the star formation event and the processes that regulated it. We analyze the Orion Nebula Cluster (ONC),…
In an effort to better understand the details of the stellar structure and evolution of metal poor stars, the Gemini North telescope was used on two occasions to take speckle imaging data of a sample of known spectroscopic binary stars and…
This doctoral thesis studies stellar multiplicity in the solar neighborhood (d < 10 pc) and in systems hosting planets (d < 100 pc). Using data from the Washington Double Star Catalogue, Gaia DR3, and a comprehensive literature review, it…
We report the discovery of large-amplitude, periodic X-ray emission from the O7 V star theta^1 Orionis C, the central star of the Orion Nebula. Ten ROSAT HRI snapshots of the Trapezium cluster taken over the course of 21 days show that the…
We report an optical photometric survey of 0.89 sq. degrees of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest density region within Orion OB1b. We have developed a…
In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on…
We present Adaptive Optics (AO) near infrared (NIR) observations using VLT/NACO and Keck/NIRC2 of ODISEA targets. ODISEA is an ALMA survey of the entire population of circumstellar discs in the Ophiuchus molecular cloud. From the whole…
Open cluster (OC) stars share the same age and metallicity, and, in general, their age and mass can be estimated with higher precision than for field stars. For this reason, OCs are considered an important laboratory to study the relation…
We present results of our large scale, optical, multi-epoch photometric survey of ~180 square degrees across the Orion OB1 association, complemented with extensive follow up spectroscopy. We map and characterize in an uniform way the…
We present the full results of our 3-year long Submillimeter Array survey of protoplanetary disks in the Orion Nebula Cluster. We imaged 23 fields at 880 microns and 2 fields at 1330 microns, covering an area of ~6.5 arcmin^2 and containing…
(abridged) A scenario for the formation of multiple co-eval populations separated in age by about 1 Myr in very young clusters (VYCs, ages less than 10 Myr) and with masses in the range 600-20000 Msun is outlined. It rests upon a converging…
Binaries are excellent astrophysical laboratories that provide us with direct measurements of fundamental stellar parameters. Compared to single isolated star, multiplicity induces new processes, offering the opportunity to confront our…