Distortion of secondaries in semi-detached binaries and the cataclysmic variable period minimum

Free access article

Issue		A&A Volume 389, Number 2, July II 2002


Page(s)		485 - 493
Section		Formation, structure and evolution of stars
DOI		http://dx.doi.org/10.1051/0004-6361:20020622

A&A 389, 485-493 (2002)
DOI: 10.1051/0004-6361:20020622

Distortion of secondaries in semi-detached binaries and the cataclysmic variable period minimum

V. Renvoizé¹, I. Baraffe^{1, 2}, U. Kolb³ and H. Ritter²

¹ C.R.A.L (UMR 5574 CNRS), École Normale Supérieure, 69364 Lyon Cedex 07, France
    e-mail: vrenvoiz, ibaraffe@ens-lyon.fr
² Max-Planck Institut für Astrophysik, Karl-Schwarzschild-str.1, 85741 Garching, Germany
    e-mail: hsr@mpa-garching.mpg.de
³ Department of Physics & Astronomy, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK
    e-mail: u.c.kolb@open.ac.uk

(Received 27 December 2001 / Accepted 15 April 2002 )

Abstract
Based on SPH simulations, we quantify the geometrical distortion effect due to tidal and rotational forces on polytropic secondaries in semi-detached binaries. The main effect is an expansion of the polytropic star, with an effect on the radius of ~5%-12%, depending on the polytropic index and the mass ratio. We apply such distortion effects to the secular evolution of secondaries in cataclysmic variable systems. We focus on systems below the 2-3 h period gap and that approach the minimum period. We find a significant increase of the predicted minimum period (~4% if changes in the secondary's thermal relaxation are approximately taken into account). Though an improvement, the effect is not big enough to solve the mismatch between predicted and observed minimum period at 80 min.

Key words: stars: binaries: close -- stars: low-mass, brown dwarfs -- stars: evolution -- stars: novae, cataclysmic variables

Offprint request: V. Renvoizé, vrenvoiz@ens-lyon.fr

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.