SALT spectroscopy of the HMXB associated with the LMC supernova remnant MCSNR J0513−6724

We report the results of optical \'echelle spectroscopy with Southern African Large Telescope (SALT) mass donor star BSDL\,923 in neutron (NS) high-mass X-ray binary XMMU\,J051342.6$-$672412 associated LMC supernova remnant (SNR) MCSNR\,J0513$-$6724. found that is a B0.7\,III double peaked emission lines originating circumbinary disk-like structure. This classification and presence double-peaked imply Be star. Modelling stellar atmosphere code {\sc fastwind} was used to derive effective temperature $T_{\rm eff}=27\pm1$\,kK, surface gravity $\log g=3.22\pm0.10$, projected rotational velocity $v\sin i\approx100\pm45 \, \kms$, colour excess $E(B-V)=0.53\pm0.05$\,mag, luminosity $\log(L_*/\lsun)=5.46\pm0.10$ BSDL\,923, as well show this polluted $\alpha$-elements (O, Mg Si) from ejecta. also NS orbiting an eccentric ($e=0.158\pm0.061$) orbit orbital period $1.280\pm0.006$\,d semi-major axis $17\pm3 \rsun$, radius $25\pm5 \,\rsun$. speculate embedded either because it kicked at birth towards or inflation caused by energy input blast wave. Using long-slit SALT, we searched for possible signs SNR shell 2D spectrum, but did not find them. lack detection consistent young age ($\approx4^{+2} _{-1}$\,kyr) MCSNR\,J0513$-$6724, implying still adiabatic (non-radiative) phase.