Context : WASP-10b , a non-inflated hot Jupiter , was discovered around a K-dwarf in a near circular orbit ( \sim 0.06 ) .
Since its discovery in 2009 , different published parameters for this system have led to a discussion about the size , density , and eccentricity of this exoplanet .

Aims : In order to test the hypothesis of a circular orbit for WASP-10b , we have observed its secondary eclipse in the Ks-band , where the contribution of planetary light is high enough to be detected from the ground .

Methods : Observations were performed with the OMEGA2000 instrument at the 3.5-meter telescope at Calar Alto ( Almería , Spain ) , in staring mode during 5.4 continuous hours , with the telescope defocused , monitoring the target during the expected secondary eclipse .
A relative light curve was generated and corrected from systematic effects , using the Principal Component Analysis ( PCA ) technique .
The final light curve was fitted using a transit model to find the eclipse depth and a possible phase shift .

Results : The best model obtained from the Markov Chain Monte Carlo analysis resulted in an eclipse depth of \Delta F of 0.137 \% ^ { +0.013 \% } _ { -0.019 \% } and a phase offset of \Delta \phi of -0.0028 ^ { +0.0005 } _ { -0.0004 } .
The eclipse phase offset derived from our modeling has systematic errors that were not taken into account and should not be considered as evidence of an eccentric orbit .
The offset in phase obtained leads to a value for |e \cos { \omega } | of 0.0044 .
The derived eccentricity is too small to be of any significance .

Conclusions :