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Aquila X--1: a low inclination soft X-ray transient

T. Shahbaz·J. R. Thorstensen·P. A. Charles·N. D. Sherman
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Abstract

We have obtained I-band photometry of the neutron star X-ray transient Aql X--1 during quiescence. We find a periodicity at 2.487 cd-1, which we interpret as twice the orbital frequency (19.30+/-0.05 h). Folding the data on the orbital period, we model the light curve variations as the ellipsoidal modulation of the secondary star. We determine the binary inclination to be 20--31 degrees (90 per cent confidence) and also 95 per cent upper limits to the radial velocity semi-amplitude and rotational broadening of the secondary star to be 117 kms-1 and 50 kms-1 respectively.

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T. Shahbaz, J. R. Thorstensen, P. A. Charles, N. D. Sherman. 1998-01-24. Aquila X--1: a low inclination soft X-ray transient. https://doi.org/10.1046/j.1365-8711.1998.01474.x

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