On the eclipsing nature of

Free access article

Issue		A&A Volume 369, Number 2, April II 2001


Page(s)		561 - 573
Section		Formation, structure and evolution of stars
DOI		http://dx.doi.org/10.1051/0004-6361:20010194

A&A 369, 561-573 (2001)
DOI: 10.1051/0004-6361:20010194

On the eclipsing nature of $\mathsf{CPD-59\degr2628}$

L. M. Freyhammer^{1, 2}, J. V. Clausen³, T. Arentoft¹ and C. Sterken¹

¹ University of Brussels (VUB), Pleinlaan 2, 1050 Brussels, Belgium
² Royal Observatory of Belgium, Ringlaan 3, 1180 Brussels, Belgium
³ Niels Bohr Institute for Astronomy, Physics and Geophysics; Astronomical Observatory, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark

(Received 9 August 2000 / Accepted 24 January 2001)

Abstract
The spectroscopic binary CPD -59°2628 (Sp = O9.5 V) has been discovered to be a detached eclipsing binary, and we present an analysis based on new light curves, published spectroscopy and two new high-resolution spectra. uvby light curves from more than 2000 observations are analysed with the WINK and the Wilson-Devinney (WD) programs. Geometric distortions and photometric effects from the proximity of the components are included in the computations. The detached system has a close circular orbit of high inclination and high maximum projected velocities. We find a photometric period $P=1\fd47$ which is consistent with the spectroscopy-binary period by Solivella & Niemela (1999). We use this period to rematch the misidentified radial velocities from Levato et al. (1991) and apply them in an analysis using the method of Lehmann-Filhes. We find that CPD -59°2628 is a young system close to the ZAMS. Its distance is $2.6\pm0.1$ kpc and it has a systemic velocity of -19 km s^-1, confirming its membership in the cluster Trumpler 16 (radial velocity -23.5 km s^-1). The temperatures are 32 000 K for the hotter star (A) and 30 000 K for the cooler (B). We determine the absolute dimensions (solar units): $M_A=14.0\pm2.0$ , $R_A=5.29\pm0.26$ , $M_B=11.7\pm1.8$ and $R_B=4.38\pm0.22$ . By adopting E(b-y)=0.306, we get $M_{{\rm bol},A}=-6.3\pm0.1$ , $M_{V,A}=-3.2\pm0.1$ , $M_{{\rm bol},B}=-5.6\pm0.1$ and $M_{V,B}=-2.7\pm0.1$ . Theoretical stellar models from Claret (1995), including convective-core overshooting and mass loss for a composition (X=0.70, Z=0.02), appear to fit the components at an age of ~2 Myr.

Key words: stars: individual: $\rm CPD -59\degr2628$ -- stars: binaries: spectroscopic -- stars: binaries: eclipsing -- stars: distances -- stars: early-type

Offprint request: L. M. Freyhammer, lfreyham@vub.ac.be

SIMBAD Objects

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.