We present spectroscopic and photometric observations of the eclipsing binary V32 located in the central field of the globular cluster NGC 6397 .
The variable is a single-line spectroscopic binary with an orbital period of 9.8783 d and a large eccentricity of e = 0.32 .
Its systemic velocity ( \gamma = 20.7 km s ^ { -1 } ) and metallicity ( [ Fe/H ] \sim -1.9 ) are both consistent with cluster membership .
The primary component of the binary is located at the top of the main-sequence turn-off on the cluster color-magnitude diagram .
Only a shallow primary eclipse is observed in the light curve .
Based on stellar models for an age of 12 Gyr and the mass-function derived from the radial velocity curve , we estimate the masses to be M _ { p } = 0.79 M _ { \odot } and M _ { s } = 0.23 M _ { \odot } .
The light curve of V32 can be reproduced by adopting R _ { p } = 1.569 R _ { \odot } and R _ { s } = 0.236 R _ { \odot } for the radii and i = 85.44 deg for the system inclination .
The system geometry precludes observations of the secondary eclipse .
The large eccentricity of the orbit is puzzling given that for metal poor , halo binaries the transition from circular to eccentric orbit occurs at an orbital period of about 20 days .
We suppose that the orbit of V32 was modified relatively recently by dynamical interaction with other cluster star ( s ) .
An alternative explanation of the observed eccentricity calls for the presence of a third body in the system .