Gebran, M. ; Monier, R. ; Royer, F. ; Lobel, A. ; Blomme, R.

published in Putting A Stars into Context: Evolution, Environment, and Related Stars, pp. 193-198 (2014)

Abstract: A programme to observe all the A dwarfs brighter than V = 6.5 mag in open clusters of various ages, and also in the field, was initiated several years ago. We carried out high-resolution, high signal-to-noise spectroscopy of stars well distributed in mass along the main sequence. This paper presents a current status of results for microturbulent velocities for A and F dwarfs. Microturbulent velocities were derived iteratively by fitting grids of synthetic spectra, calculated for LTE, to observations of 61 A-type field stars, and to 55 A and 58 F stars in the open clusters Pleiades, Coma, Hyades, and the Ursa Major moving group. We compared our results to recent ones, and found a good agreement with analytical formulations for standard microturbulence. Our results also indicate a broad maximum in microturbulent velocity across the range A5V to about A9V, and decreasing to ˜ 1 km s^{-1} for cooler and hotter stars, as also found by Smalley te{Smalley2004}. We also compare our results with the preliminary ones by Lobel et al. te{Lobel2013} from the Gaia-ESO Public Spectroscopic Survey.

Links: link