The radial velocities were analysed using the [RVSIM]{} software program [@Kan07]. The parameters are presented in Table2 and the fits are compared with the observations in Fig.1.

  ------------- --------- ------------- ---------- ------------- ---------- --
   HJD–2400000   Orbital                                                    
                  Phase     $V_{\rm P}$  $\sigma$    $V_{\rm S}$  $\sigma$  
   54638.34598   0.6729            84.2    0.6             -83.2    0.7     
   54639.33703   0.8984            44.2    0.9             -55.4    0.7     
   54640.33176   0.1248           -81.2    1.1              55.6    1.1     
   54641.34108   0.3545           -81.2    0.9              51.4    0.4     
   54642.34823   0.5837            50.1    1.1             -55.3    1.1     
   54643.35360   0.8124            81.5    1.0             -84.3    0.6     
   54644.38749   0.0477           -41.3    1.4              21.2    0.7     
   54647.37993   0.7287            92.4    0.7             -88.5    0.7     
   54649.36320   0.1800          -100.2    0.8              66.5    1.2     
   54651.35779   0.6339            71.4    0.8             -71.2    1.3     
   54654.34120   0.3129           -95.6    0.7              66.2    1.1     
  ------------- --------- ------------- ---------- ------------- ---------- --

  : Heliocentric radial velocities of V2653Oph. The columns give the heliocentric Julian date, orbital phase and the radial velocities of the two components with the corresponding standard deviations.

  -------------------------- --------------- --------------- -- -- -- -- -- -- --
  Parameter                                                                    
                                 Primary        Secondary                      
  $K$ (kms$^{-1}$)              $ 83\pm$1       $93\pm$1                       
  $V_\gamma$ (kms$^{-1}$)                                                      
  Average O-C (kms$^{-1}$)         0.5             0.9                         
  $a\sin i$ ($R_{\odot}$)                                                      
  $M\sin^3i$ ($M_{\odot}$)    1.50$\pm$0.10   1.25$\pm$0.18                    
  $e$                                                                          
  -------------------------- --------------- --------------- -- -- -- -- -- -- --

  : Results of the radial velocity analysis for V2653Oph.

Determination of the atmospheric 