Showing papers by "J. H. J. de Bruijne published in 1997"
01 Aug 1997
TL;DR: Hoogerwerf et al. as mentioned in this paper presented a new procedure for the identification of moving groups using a combination of two independent member selection methods, one is a modern implementation of a classical convergent point method for proper motion data and the other objectively identifies moving groups in velocity space using proper motions and parallaxes.
Abstract: 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 convergent point method for proper motion data. The other objectively identifies moving groups in velocity space using proper motions and parallaxes. We briefly describe both methods, and illustrate their power by applying them to Hipparcos measurements of a field containing the Upper Scorpius subgroup of the Scorpio-Centaurus association (Sco OB2). We show how our membership selection procedure not only improves the list of previously known B and A-type members, but also identifies many new members, including a significant number of F stars. We apply our procedure to other nearby OB associations elsewhere in these proceedings (Hoogerwerf et al.: de Zeeuw et al.).
17 citations
Journal Article•
TL;DR: In this article, the authors 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 candidate member stars distributed over 21 fields on the sky.
Abstract: 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 candidate member stars distributed over 21 fields on the sky. We use a new method to identify moving groups in these fields (see de Bruijne et al., these proceedings). Previously, astrometric membership in nearly all the nearby OB associations was known only for stars with spectral types earlier than B5. The Hipparcos measurements now allow us to identify members down to late F. This census provides a firm basis for studies of galactic and extragalactic star forming regions.
4 citations
Posted Content•
TL;DR: It is shown how the membership selection procedure not only improves the list of previously known B and A-type members, but also identifies many new members, including a significant number of F stars.
Abstract: 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 convergent point method for proper motion data. The other objectively identifies moving groups in velocity space using proper motions and parallaxes. We briefly describe both methods, and illustrate their power by applying them to Hipparcos measurements of a field containing the Upper Scorpius subgroup of the Scorpio-Centaurus association (Sco OB2). We show how our membership selection procedure not only improves the list of previously known B and A-type members, but also identifies many new members, including a significant number of F stars. We apply our procedure to other nearby OB associations elsewhere in these proceedings (Hoogerwerf et al.; de Zeeuw et al.).
2 citations
Posted Content•
TL;DR: In this paper, the authors 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 candidate member stars distributed over 21 fields on the sky.
Abstract: 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 candidate member stars distributed over 21 fields on the sky. We use a new method to identify moving groups in these fields (see de Bruijne et al., these proceedings). Previously, astrometric membership in nearly all the nearby OB associations was known only for stars with spectral types earlier than B5. The Hipparcos measurements now allow us to identify members down to late F. This census provides a firm basis for studies of galactic and extragalactic star forming regions.
1 citations
Posted Content•
TL;DR: De Bruijne et al. as discussed by the authors developed a new procedure to identify moving groups, and applied it to carry out a census of the nearby OB associations based on Hipparcos parallaxes and proper motions.
Abstract: 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 motions (see de Bruijne et al. and de Zeeuw et al. elsewhere in this volume). Here we present three illustrative cases. For $\alpha$ Persei our method allows us to refine the bright end of the membership list, while for Collinder 121 the Hipparcos data change the whole appearance of the association. Finally, we report the discovery of a new association in the field of Cepheus OB2.
1 citations
01 Aug 1997
TL;DR: De Bruijne et al. as discussed by the authors developed a new procedure to identify moving groups, and applied it to carry out a census of the nearby OB associations based on Hipparcos parallaxes and proper motions.
Abstract: 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 motions (see de Bruijne et al. and de Zeeuw et al. elsewhere in this volume). Here we present three illustrative cases. For $\alpha$ Persei our method allows us to refine the bright end of the membership list, while for Collinder 121 the Hipparcos data change the whole appearance of the association. Finally, we report the discovery of a new association in the field of Cepheus OB2.