5 papers
Improved Methods for Identifying Moving Groups
J. H. J. de Bruijne, R. Hoogerwerf, A. G. A. Brown +2
We present a new procedure for the identification of moving groups. It is a combination of two independent member selection methods. One is a modern implementation of a classical c…
Structure and Evolution of Nearby OB Associations
P. T. de Zeeuw, A. G. A. Brown, J. H. J. de Bruijne +4
We present the first results of a comprehensive census of the stellar content of the nearby OB associations based on Hipparcos positions, proper motions and parallaxes for 12842 ca…
New Results for Three Nearby OB Associations
R. Hoogerwerf, J. H. J. de Bruijne, A. G. A. Brown +3
We have developed a new procedure to identify moving groups, and have applied it to carry out a census of the nearby OB associations based on Hipparcos parallaxes and proper motion…
Some Considerations in making full Use of the Hipparcos Catalogue
A. G. A. Brown, F. Arenou, F. van Leeuwen +2
This contribution is intended as a `rough guide' to the Hipparcos Catalogue for the non-expert user. Some general aspects of the use of astrometric data are discussed as well as Hi…
High S/N Echelle Spectroscopy in Young Stellar Groups II. Rotational Velocities of Early-Type Stars in Sco OB2
A. G. A. Brown, W. Verschueren
We investigate the rotational velocities of early-type stars in the Sco OB2 association. We measure \vsini\ for 156 established and probable members of the association. The measure…