  Since its launch, the INTErnational Gamma-Ray Astrophysics Laboratory
(INTEGRAL) satellite has discovered hundreds of X-ray sources, many of which
lack proper classification. This mission also led to the discovery of new
categories of high mass X-ray binaries (HMXB). We use the spectra of the
X-Shooter instrument at the Very Large Telescope (VLT) of the European Southern
Observatory (ESO) to better understand the nature of 3 accreting binaries (IGR
J10101-5654, IGR J11435-6109 and IGR J12489-6243) discovered by INTEGRAL. We
mainly focused on the lines and continuum from the X-Shooter spectra. We used
atlases to constrain the nature of the sources and also complemented the
spectra with measurements taken by Spitzer and the Wide-field Infrared Survey
Explorer (WISE) in infrared, and parallaxes from Gaia for the distances. We
determined the nature of each binary system: a BeHMXB system with a companion
star of spectral type B0.5Ve with peculiar carbon emission for IGR J10101-5654
and IGR J11435-6109, and a CV system with an evolved K star (K0IV-K2IV) for IGR
J12489-6243. We also estimated some geometrical parameters of the decretion
disk and neutron star's orbit in the case of IGR J11435-6109.
