Mason, A. B.; Clark, J. S.; Norton, A. J.; Crowther, P. A.; Tauris, T. M.; Langer, N.; Negueruela, I. and Roche, P.
PDF (Accepted Manuscript)
- Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
|DOI (Digital Object Identifier) Link:||http://doi.org/10.1111/j.1365-2966.2012.20596.x|
|Google Scholar:||Look up in Google Scholar|
We report near-infrared radial velocity measurements of the recently identified donor star in the high mass X-ray binary system OAO 1657-415 obtained in the H band using ISAAC on the VLT.
Cross-correlation methods were employed to construct a radial velocity curve with a semi-amplitude of 22.1 ± 3.5 km s-1. Combined with other measured parameters of this system this provides a dynamically determined neutron star mass of 1.42 ± 0.26 M⊙ and a mass of 14.3 ± 0.8 M⊙ for the Ofpe/WN9 highly evolved donor star.
OAO 1657-415 is an eclipsing High Mass X-ray binary pulsar with the largest eccentricity and orbital period of any within its class. Of the ten known eclipsing X-ray binary pulsars OAO 1657-415 becomes the ninth with a dynamically determined neutron star mass solution and only the second in an eccentric system. Furthermore, the donor star in OAO 1657-415 is much more highly evolved than the majority of the supergiant donors in other High Mass X-ray binaries (HMXBs), joining a small but growing list of HMXBs donors with extensive hydrogen depleted atmospheres.
Considering the evolutionary development of OAO 1657-415, we have estimated the binding energy of the envelope of the mass donor and find that there is insufficient energy for the removal of the donor's envelope via spiral-in, ruling out a Common Envelope evolutionary scenario. With its non-zero eccentricity and relatively large orbital period the identification of a definitive evolutionary pathway for OAO1657-415 remains problematic, we conclude by proposing two scenarios which may account for OAO1657-415 current orbital configuration.
|Item Type:||Journal Article|
|Copyright Holders:||2012 The Authors|
|Keywords:||eclipsing binaries; binaries; OAO 1657−415; Wolf–Rayet; X-ray binaries|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Andrew Norton|
|Date Deposited:||03 Feb 2012 09:29|
|Last Modified:||23 Feb 2016 21:16|
|Share this page:|
Download history for this item
These details should be considered as only a guide to the number of downloads performed manually. Algorithmic methods have been applied in an attempt to remove automated downloads from the displayed statistics but no guarantee can be made as to the accuracy of the figures.