New high-resolution spectroscopy and BVR photometry , together with literature data , on the Gould ’ s Belt close binary systems GG Lup and \mu ^ { 1 } Sco are presented and analysed .

In the case of GG Lup , light and radial velocity curve fittings confirm a near-Main-Sequence picture of a pair of close stars .
Absolute parameters are found , to within a few percent , thus : M _ { 1 } = 4.16 \pm 0.12 , M _ { 2 } = 2.64 \pm 0.12 , R _ { 1 } = 2.42 \pm 0.05 , R _ { 2 } = 1.79 \pm 0.04 , ( \odot ) ; T _ { 1 } \sim 13000 , T _ { 2 } \sim 10600 ( K ) ; photometric distance \sim 160 ( pc ) .
The high eccentricity and relatively short period ( 105 y ) of apsidal revolution may be related to an apparent ‘ slow B-type pulsator ’ ( SPB ) oscillation .
Disturbances of the outer envelope of at least one of the components then compromise comparisons to standard evolutionary models , at least regarding the age of the system .
A rate of apsidal advance is derived , which allows a check on the mean internal structure constant \overline { k _ { 2 } } = 0.0058 \pm 0.0004 .
This is in agreement with values recently derived for young stars of solar composition and mass \sim 3 { \odot } .

For \mu ^ { 1 } Sco , we agree with previous authors that the secondary component is considerably oversized for its mass , implying binary ( interactive ) stellar evolution , probably of the ‘ Case A ’ type .
The primary appears relatively little affected by this evolution , however .
Its parameters show consistency with a star of its derived mass at age about 13 My , consistent with the star ’ s membership of the Sco-Cen OB2 Association .
The absolute parameters are as follows : M _ { 1 } = 8.3 \pm 1.0 , M _ { 2 } = 4.6 \pm 1.0 , R _ { 1 } = 3.9 \pm 0.3 , R _ { 2 } = 4.6 \pm 0.4 , ( \odot ) ; T _ { 1 } \sim 24000 , T _ { 2 } \sim 17000 ( K ) ; photometric distance \sim 135 ( pc ) .