This paper presents a photometric and spectroscopic study of the bright blue eclipsing binary LMC-SC1-105 , selected from the OGLE catalog as a candidate host of very massive stars ( \geq 30 \mbox { M$ { } _ { \odot } $ } ) .
The system is found to be a double-lined spectroscopic binary , which indeed contains massive stars .
The masses and radii of the components are M _ { 1 } = 30.9 \pm 1.0 \mbox { M$ { } _ { \odot } $ } , M _ { 2 } = 13.0 \pm 0.7 \mbox { M$ { } _ { \odot } $ } , and R _ { 1 } = 15.1 \pm 0.2 \mbox { R$ { } _ { \odot } $ } , R _ { 2 } = 11.9 \pm 0.2 \mbox { R$ { } _ { \odot } $ } , respectively .
The less massive star is found to be filling its Roche lobe , indicating the system has undergone mass-transfer .
The spectra of LMC-SC1-105 display the Struve-Sahade effect , with the He i lines of the secondary appearing stronger when it is receding and causing the spectral types to change with phase ( O8 + O8 to O7 + O8.5 ) .
This effect could be related to the mass-transfer in this system .
To date , accurate ( \leq 10 \% ) fundamental parameters have only been measured for 15 stars with masses greater than 30 M _ { \odot } , with the reported measurements contributing valuable data on the fundamental parameters of very massive stars at low metallicity .
The results of this work demonstrate that the strategy of targeting the brightest blue stars in eclipsing binaries is an effective way of studying very massive stars .