J/A+A/463/671 Rotational velocities of A-type stars. III. (Royer+, 2007) ================================================================================ Rotational velocities of A-type stars. III. Velocity distributions. Royer F., Zorec J., Gomez A.E. =2007A&A...463..671R ================================================================================ ADC_Keywords: Stars, A-type ; Rotational velocities Keywords: stars: early-type - stars: rotation Abstract: A sample of vsini of B9 to F2-type main sequence single stars has been built from highly homogeneous vsini parameters determined for a large sample cleansed of objects presenting the Am and Ap phenomenon as well as of all known binaries. The aim is to study the distributions of rotational velocities in the mass range of A-type stars for normal single objects. Robust statistical methods are used to rectify the vsini distributions for the projection effect and the error distribution. The equatorial velocity distributions are obtained for about 1100 stars divided in six groups defined by the spectral type, under the assumption of randomly orientated rotational axes. We show that late B and early A-type main-sequence stars have genuine bimodal distributions of true equatorial rotational velocities probably due to angular momentum loss and redistribution that the star underwent before reaching the main sequence. A striking lack of slow rotators is noticed among intermediate and late A-type stars. Description: The total sample of stellar rotational velocities is presented. The 1541 stars are listed with their projected rotational velocity value (vsini), their spectral type, the subgroup in which they are classified according to their spectral type, and whether or not they are known to a chemically peculiar object (CP) and/or a close binary object (CB). File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table4.dat 35 1541 List of the 1541 B9- to F2-type stars, with their vsini value, spectral type, associated subgroup and classification -------------------------------------------------------------------------------- See also: III/22 : Rotation of Evolving A and F Stars (Danziger+ 1972) III/226 : Rotational Velocities of Stars (Glebocki+ 2000) J/A+AS/118/545 : Rotational velocities of F dwarfs (Groot+, 1996) J/ApJ/573/359 : Rotational velocities of B stars from BSC (Abt+, 2002) J/A+A/398/647 : Rotational velocities of F and G stars (Reiners+, 2003) J/A+A/381/105 : Rotational velocities of A-type stars. I. (Royer+, 2002) J/A+A/393/897 : Rotational velocities of A-type stars II. (Royer+, 2002) Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 I6 --- HD HD number 8- 10 I3 km/s vsini Projected rotational velocity 12- 22 A11 --- SpType MK spectral type 25- 29 A5 --- Subgroup Subgroup in spectral type 31- 35 A5 --- Class Classification (1) -------------------------------------------------------------------------------- Note (1): Classification as follows: CP = Chemically peculiar star CB = Close binary star blank = "normal" star -------------------------------------------------------------------------------- Acknowledgements: Frederic Royer, frederic.royer(at)obspm(fr) ================================================================================ (End) F. Royer [Obs. de Paris, France], P. Vannier [CDS] 24-Nov-2006