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A.B. Mason, A.J. Norton, J.S. Clark, P. Roche & I. Negueruela

High Mass X-ray Binaries in the NIR: Orbital solutions of two highly obscured systems.

(Volume 80 - Année 2011)
Article
Open Access

Abstract

The maximum mass of a neutron star (NS) is poorly defined. Theoretical attempts to define this mass have thus far been unsuccessful. Observational results currently provide the only means of narrowing this mass range down. Eclipsing X-ray binary (XRB) pulsar systems are the only interacting binaries in which the mass of the NS may be measured directly. Only 10 such systems are known to exist, 6 of which have yielded NS masses in the range 1.06 - 1.86 Mo. We present the first orbital solutions of two further eclipsing systems, OAO 1657-415 and EXO 1722-363, whose donor stars have only recently been identified. Using observations obtained with the VLT/ISAAC NIR spectrograph, our initial work was concerned with providing an accurate spectral classification of the two counterpart stars, leading to a consistent explanation of the mechanism for spin period evolution of OAO 1657-415. Calculating radial velocities allowed orbital solutions for both systems to be computed. These are the first accurate determinations of the NS and counterpart masses in XRB pulsar systems to be made employing NIR spectroscopy.

To cite this article

A.B. Mason, A.J. Norton, J.S. Clark, P. Roche & I. Negueruela, «High Mass X-ray Binaries in the NIR: Orbital solutions of two highly obscured systems.», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 80 - Année 2011, 699 - 703 URL : https://popups.ulg.ac.be/0037-9565/index.php?id=3164.

About: A.B. Mason

The Open University, Milton Keynes, UK, a.mason@open.ac.uk

About: A.J. Norton

The Open University, Milton Keynes, UK

About: J.S. Clark

The Open University, Milton Keynes, UK

About: P. Roche

The Open University, Milton Keynes, UK

About: I. Negueruela

Universidad de Alicante, Alicante, Spain