VSOP: the variable star one-shot project

Abstract

Context. About 500 new variable stars enter the General Catalogue of Variable Stars (GCVS) every year. Most of them however lack spectroscopic observations, which remains critical for a correct assignement of the variability type and for the understanding of the object. Aims. The Variable Star One-shot Project (VSOP) is aimed at (1) providing the variability type and spectral type of all unstudied variable stars, (2) process, publish, and make the data available as automatically as possible, and (3) generate serendipitous discoveries. This first paper describes the project itself, the acquisition of the data, the dataflow, the spectroscopic analysis and the on-line availability of the fully calibrated and reduced data. We also present the results on the 221 stars observed during the first semester of the project. Methods. We used the high-resolution echelle spectrographs HARPS and FEROS in the ESO La Silla Observatory (Chile) to survey known variable stars. Once reduced by the dedicated pipelines, the radial velocities are determined from cross correlation with synthetic template spectra, and the spectral types are determined by an automatic minimum distance matching to synthetic spectra, with traditional manual spectral typing cross-checks. The variability types are determined by manually evaluating the available light curves and the spectroscopy. In the future, a new automatic classifier, currently being developed by members of the VSOP team, based on these spectroscopic data and on the photometric classifier developed for the COROT and Gaia space missions, will be used. Results. We confirm or revise spectral types of 221 variable stars from the GCVS. We identify 26 previously unknown multiple systems, among them several visual binaries with spectroscopic binary individual components. We present new individual results for the multiple systems V349 Vel and BC Gru, for the composite spectrum star V4385 Sgr, for the T Tauri star V1045 Sco, and for DM Boo which we re-classify as a BY Draconis variable. The complete data release can be accessed via the VSOP web site.

HD 66051, an eclipsing binary hosting a highly peculiar, HgMn-related star

“…However, a high-resolution spectrum of the star is available in the archive of the ‘Variable Star One-shot Project’ 33 , which was taken with the HARPS instrument (High Accuracy Radial velocity Planet Searcher 34 ) at the ESO La Silla 3.6 m telescope in Chile. The star was observed on JD 2453827.518802, which corresponds to orbital phase ϕ orb  = 0.46.…”

SPOTS: The Search for Planets Orbiting Two Stars

“…XZ Pic = HIP 27134 = CD-59 1125: short-period SB1 according to sparse RV measurements (Dall et al 2007;Torres et al 2006;Cutispoto et al 1999). Age indicators based on activity and rotation are likely biased by tidal locking between the components.…”

Automated supervised classification of variable stars in the CoRoT programme

“…equivalent line widths) can improve the classification performance, both for supervised and unsupervised methods. An extended classifier that also uses spectroscopic attributes could be used and provided by e.g the VSOP project (variable star oneshot project, Dall et al 2007). Fig.…”