The Belgian Repository of fundamental Atomic data and Stellar Spectra (BRASS) aims to provide one of the largest systematic and homogeneous quality assessment to date of literature atomic data required for stellar spectroscopy. By comparing state-of-the-art synthetic spectrum calculations with extremely high-quality observed benchmark spectra, we have critically evaluated fundamental atomic data, such as line wavelengths and oscillator strengths, for thousands of astrophysically-relevant transitions found in the literature and across several major atomic data repositories. These proceedings provide a short overview of the BRASS project to date, highlighting our recent efforts to investigate and quality-assess the atomic literature data pertaining to over a thousand atomic transitions present in FGK-type stellar spectra. BRASS provides all quality assessed data, theoretical spectra, and observed spectra in a new interactive database under development at brass.sdf.org.

Luminous Blue Variables (LBVs) are a brief phase in the evolution of massive stars, but a very important one. The giant eruptions remain enigmatic, but the discovery of the flagship LBV η Car to be a five-year highly eccentric binary put focus on possible binarity induced mechanism for these outbursts, and prompted binarity searches among LBVs. While several wide LBV binaries were identified, HR Car is the first system found to be similar to η Car, i.e., relatively close & eccentric.

We investigate the physical properties of large-scale wind structures around massive hot stars with radiatively-driven winds. We observe Discrete Absorption Components (DACs) in optical He i P Cygni lines of the LBV binary MWC 314 (Porb = 60.8 d). The DACs are observed during orbital phases when the primary is in front of the secondary star. They appear at wind velocities between −100 km s−1 and −600 km s−1 in the P Cyg profiles of Hei λ5875, λ6678, and λ4471, signaling high-temperature expanding wind regions of enhanced density and variable outflow velocity. The DACs can result from wave propagation linked to the orbital motion near the low-velocity wind base. The He i lines indicate DAC formation close to the primary's surface in high-temperature wind regions in front of its orbit, or in dynamical wind regions confined between the binary stars. We observed the DACs with Mercator-HERMES on 5 Sep 2009, 5 May 2012, and 6 May 2014 when the primary is in front of the secondary star. XMM-Newton observations of 6 May 2014 significantly detected MWC 314 in X-rays at an average rate of ~0.015 cts s−1.

Spectroscopy and photometry of eclipsing binaries and Cepheids (using the Baade–Wesselink method) yield primary distance markers applicable to the Local Group of galaxies. The technique of disentangling spectra has proved helpful in resolving stellar physical parameters. Our method also allows us to disentangle interstellar absorption lines and, thus, to complement the radial-velocity structure of the interstellar medium with an (otherwise unattainable) upper limit to its distance. The mapping of the spatial and kinematic structure of the stellar and interstellar components of the Magellanic Clouds and Stream enables constraining their tidal evolution and, thus, of the mass of the Galaxy.

We have chosen the name of GYES, one of the mythological giants with one hundred arms,offspring of Gaia and Uranus, for our instrument study of a multifibre spectrograph forthe prime focus of the Canada-France-Hawaii Telescope. Such an instrument could provide anexcellent ground-based complement for the Gaia mission and a northern complement to theHERMES project on the AAT. The CFHT is well known for providing a stable prime focusenvironment, with a large field of view, which has hosted several imaging instruments, buthas never hosted a multifibre spectrograph. Building upon the experience gained at GÉPIwith FLAMES-Giraffe and X-Shooter, we are investigating the feasibility of a highmultiplex spectrograph (about 500 fibres) over a field of view one degree in diameter. Weare investigating an instrument with resolution in the range 15 000 to 30 000, whichshould provide accurate chemical abundances for stars down to 16th magnitude and radialvelocities, accurate to 1 km s-1 for fainter stars. The study is led byGÉPI-Observatoire de Paris with a contribution from Oxford for the study of thepositioner. The financing for the study comes from INSU CSAA and Observatoire de Paris.The conceptual study will be delivered to CFHT for review by October 1st 2010.

During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V ~ 17–18. This talk presents: (i) the system which is currently developed within the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the spectra and to derive the radial and rotational velocities, (ii) the RVS expected performances and (iii) scientific returns.

Gaia will provide accurate parallaxes, spectrophotometry and spectroscopy for hundreds of thousands of emission-line stars across the whole HR diagram. In preparation for the Gaia mission, we are developing algorithms to recognize and classify emission-line stars. A large collection of ground-based spectroscopic observations has been collected and will be used for testing and training the algorithms.

Gaia will also provide information on several millions of early-type stars. Determining accurate parameters for these stars from Gaia data only will be difficult due to the AV – Teff degeneracy.

NGC 6611, Trumpler 14, Trumpler 15, Trumpler 16, and Collinder 232 are very young open clusters located in star-formation regions in the Eagle Nebula and Carina in the Milky Way, and NGC 346 in the Small Magellanic Cloud. With different instrumentation and techniques, it has been possible to detect and classify new Herbig Ae/Be and classical Be stars and to provide new tests/comparisons of the Be stars' appearance models. Special (He-strong) stars in these star-formation regions are also discussed.

Star clusters are privileged laboratories for studying the evolution of massive stars (OB stars). One particularly interesting question concerns the phases during which the classical Be stars occur, which—unlike HAe/Be stars—are not pre-main-sequence objects, nor supergiants. Rather, they are extremely rapidly rotating B-type stars with a circumstellar decretion disk formed by episodic ejections of matter from the central star. To study the impact of mass, metallicity, and age on the Be phase, we observed Small Magellanic Cloud (SMC) open clusters with two different techniques: (i) with the ESO–WFI in slitless mode, which allowed us to find the brighter Be and other emission-line stars in 84 SMC open clusters, and (ii) with the VLT–FLAMES multifiber spectrograph to determine accurately the evolutionary phases of Be stars in the Be-star-rich SMC open cluster NGC 330. Based on a comparison to the Milky Way, a model of Be stellar evolution, appearance as a function of metallicity and mass, and spectral type is developed, involving the fractional critical rotation rate as a key parameter.