Abstract
In this paper we present X-Shooter time-resolved spectroscopy and RXTE PCA light curves
of the ultra-compact X-ray binary candidate 4U 0614+091. The X-Shooter data are compared
to the GMOS data analysed previously by Nelemans et al. We confirm the presence of CIII
and OII emission features at ≈4650 Å and ≈5000 Å. The emission lines do not show evident
Doppler shifts that could be attributed to the motion of the donor star/hotspot around the
centre of mass of the binary. We note a weak periodic signal in the red-wing/blue-wing flux
ratio of the emission feature at ≈4650 Å. The signal occurs at P = 30.23 ± 0.03 min in the
X-Shooter and at P = 30.468 ± 0.006 min in the GMOS spectra when the source was in the
low/hard state. Due to aliasing effects the period in the GMOS and X-Shooter data could well
be the same. We deem it likely that the orbital period is thus close to 30 min; however, as
several photometric periods have been reported for this source in the literature already, further
c
Original language | English |
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Pages (from-to) | 2013 |
Journal | Monthly Notices of the Royal Astronomical Society |
State | Published - Mar 2013 |