Bartlett, E. S.E. S.BartlettCoe, M. J.M. J.CoeISRAEL, Gian LucaGian LucaISRAELClark, J. S.J. S.ClarkEsposito, P.P.EspositoD'Elia, V.V.D'EliaUdalski, A.A.Udalski2020-12-072020-12-0720170035-8711http://hdl.handle.net/20.500.12386/28733We present a detailed optical and X-ray study of the 2013 outburst of the Small Magellanic Cloud Be/X-ray binary SXP 7.92, as well as an overview of the last 18 years of observations from OGLE (Optical Gravitational Lensing Experiment), RXTE, Chandra and XMM-Newton. We revise the position of this source to RA(J2000) = 00:57:58.4, Dec(J2000) = -72:22:29.5 with a 1σ uncertainty of 1.5 arcsec, correcting the previously reported position by Coe et al. by more than 20 arcmin. We identify and spectrally classify the correct counterpart as a B1Ve star. The optical spectrum is distinguished by an uncharacteristically deep narrow Balmer series, with the Hα line in particular having a distinctive shell profile, I.e. a deep absorption core embedded in an emission line. We interpret this as evidence that we are viewing the system edge on and are seeing self-obscuration of the circumstellar disc. We derive an optical period for the system of 40.0 ± 0.3 d, which we interpret as the orbital period, and present several mechanisms to describe the X-ray/optical behaviour in the recent outburst, in particular the 'flares'and 'dips' seen in the optical light curve, including a transient accretion disc and an elongated precessing disc.STAMPAenArticle10.1093/mnras/stx0322-s2.0-85085987934000402849400065https://academic.oup.com/mnras/article/466/4/4659/28934612017MNRAS.466.4659BFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_6 Stars and stellar systems