Fast rotating Blue Stragglers in the globular cluster M4
  We have used high resolution spectra obtained with the spectrograph FLAMES at
the ESO Very Large Telescope to determine the kinematical properties and the
abundance patterns of 20 blue straggler stars (BSSs) in the globular cluster
M4. We found that ~ 40% of the measured BSSs are fast rotators (with rotational
velocities > 50 km/s). This is the largest frequency of rapidly rotating BSSs
ever detected in a globular cluster. In addition, at odds with what has been
found in 47 Tucanae, no evidence of carbon and/or oxygen depletion has been
revealed in the sample of 11 BSSs for which we were able to measure the
abundances. This could be due either to low statistics, or to a different BSS
formation process acting in M4.
