We investigate the luminous star ELHC 10 located in the bar of the Large Magellanic Cloud , concluding that it is a SB1 long-period eclipsing binary where the main eclipse is produced by an opaque structure hiding the secondary star .
For the more luminous component we determine an effective temperature of 6500 \pm 250 K , log g = 1.0 \pm 0.5 and luminosity 5970 L _ { \sun } .
From the radial velocities of their photospheric lines we calculate a mass function of 7.37 \pm 0.55 M _ { \sun } .
Besides Balmer and forbidden N ii emission , we find splitting of metallic lines , characterized by strong discrete absorption components ( DACs ) , alternatively seen at the blue and red side of the photospheric spectrum .
These observations hardly can be interpreted in terms of an structured atmosphere but might reflect mass streams in an interacting binary .
The primary shows signatures of s-process nucleosynthesis and might be a low-mass post-AGB star with a rare evolutionary past if the binary is semi-detached .
The peak separation and constancy of radial velocity in H \alpha suggest that most of the Balmer emission comes from a circumbinary disc .