How Close Are We To Detecting Earth-like Planets in the Habitable Zone   Using the Radial Velocity Technique?
  Discovering an Earth-like exoplanet in habitable zone is an important milestone for astronomers in search of extra-terrestrial life. While the radial velocity (RV) technique remains one the most powerful tools in detecting and characterizing exo-planetary sys- tems, we calculate the uncertainties in precision RV measurements considering stellar spectral quality factors, RV calibration sources, stellar noise and telluric contamination in different observational bandpasses and for different spectral types. We predict the optimal observational bandpass for different spectral types using the RV technique un- der a variety of conditions. We compare the RV signal of an Earth-like planet in the habitable zone (HZ) to the near future state of the art RV precision and attempt to answer the question: How close are we to detecting Earth-like planet in the HZ using the RV technique? 
Ji Wang and Jian Ge
astro-ph.EP