  The detection of planets around other stars by the measurement of the stellar
Radial Velocity (RV) variations benefits from improvements of dedicated
spectrographs, allowing to achieve a precision of 1 ms$^{-1}$ or better.
Spectral intervals within which stellar lines are contaminated by telluric
lines are classically excluded from the RV processing. We aim at estimating the
potential improvement of telluric absorption removal and subsequent extension
of the useful spectral domain on the precision of radial velocity measurements.
We developed a correction method based on the on-line web service TAPAS,
allowing to determine a synthetic atmospheric transmission spectrum for the
time and location of observations. This method was applied to the telluric
H$_{2}$O and O$_2$ absorption removal from a series of 200 ESPRESSO consecutive
exposures of the K2.5V star HD40307, available in ESO archives. We calculated
the radial velocity using the standard Cross-Correlation Function (CCF) method
and Gaussian fit of the CCF, with uncorrected spectra and the ESPRESSO standard
stellar binary mask on one hand, and telluric-corrected spectra and an
augmented binary mask with 696 additional lines on the other hand. We find that
the precision of radial velocity measurements is improved in the second case,
with a reduction of the average formal error from 1.04 ms$^{-1}$ down to 0.78
ms$^{-1}$ in the case of these ESPRESSO data and this stellar type for the red
arm. Using an estimator of the minimal error based on photon noise limit
applied to the full CCF, the error is reduced from 0.89 ms$^{-1}$ down to 0.78
ms$^{-1}$. This corresponds to a significant decrease of about 35\% of
observing time to reach the same precision in the red part.
