Rotational velocities of A-type stars. III. Velocity distributions

Aims. A sample of $v\sin i$ of B9 to F2-type main sequence single stars has been built from highly homogeneous ${v\sin i}$ 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. Methods. Robust statistical methods are used to rectify the ${v\sin i}$ 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. Results. 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.

[1]  Michael Perryman,et al.  Astronomical Applications of Astrometry: The Hipparcos and Tycho Catalogues , 2008 .

[2]  J. Zorec,et al.  Effects of gravitational darkening on the determination of fundamental parameters in fast-rotating B-type stars , 2005, astro-ph/0503381.

[3]  F. Royer,et al.  First signatures of strong differential rotation in A-type stars , 2003, Proceedings of the International Astronomical Union.

[4]  I. Howarth.  Rotation and line broadening in OBA stars , 2004 .

[5]  G. Mathys.  Rotation and Properties of A- and B-Type Chemically Peculiar Stars (Invited Review) , 2004 .

[6]  F. Fekel.  Rotational Velocities of B, A, and Early‐F Narrow‐lined Stars , 2003 .

[7]  S. Barnes.  A Connection between the Morphology of the X-Ray Emission and Rotation for Solar-Type Stars in Open Clusters , 2003, astro-ph/0303632.

[8]  P. North,et al.  Automated spectroscopic abundances of A and F-type stars using echelle spectrographs - II. Abundances of 140 A-F stars from ELODIE and CORALIE , 2002, astro-ph/0210065.

[9]  H. Levato,et al.  Rotational Velocities of B Stars , 2002 .

[10]  Andrea Richichi,et al.  CHARM: A Catalog of High Angular Resolution Measurements , 2002 .

[11]  H. Spruit.  Dynamo action by differential rotation in a stably stratified stellar interior , 2001, astro-ph/0108207.

[12]  F. Royer,et al.  Rotational velocities of A-type stars ?;?? I. Measurement of v sini in the southern hemisphere , 2001, astro-ph/0205255.

[13]  D. Soderblom,et al.  Rotational Studies of Late-Type Stars. VII. M34 (NGC 1039) and the Evolution of Angular Momentum and Activity in Young Solar-Type Stars , 2001, astro-ph/0109159.

[14]  S. Udry,et al.  The distribution of exoplanet masses , 2001, astro-ph/0105301.

[15]  C. Bailer-Jones,et al.  The Mass Dependence of Stellar Rotation in the Orion Nebula Cluster , 2001, astro-ph/0104438.

[16]  H. Abt.  Does Rotation Alone Determine Whether an A-Type Star’s Spectrum Is Abnormal or Normal? , 2000 .

[17]  Jean Kovalevsky,et al.  Astronomical Applications of Astrometry: The Hipparcos and Tycho Catalogues , 2008 .

[18]  P. North,et al.  Magnetic Ap Stars in the Hertzsprung-Russell Diagram , 2000 .

[19]  Jean-François Richard,et al.  Methods of Numerical Integration , 2000 .

[20]  B. Reipurth,et al.  Birth and Evolution of Binary Stars : poster proceedings of IAU symposium no. 200 on the formation of binary stars, 10 - 15 April 2000, Potsdam, Germany , 2000 .

[21]  A. Bowman,et al.  Applied smoothing techniques for data analysis : the kernel approach with S-plus illustrations , 1999 .

[22]  S. Grenier,et al.  Search for reference A0 dwarf stars: Masses and luminosities revisited with HIPPARCOS parallaxes , 1999 .

[23]  Richard D. Deveaux,et al.  Applied Smoothing Techniques for Data Analysis , 1999, Technometrics.

[24]  F. Nakamura,et al.  Gravitational Contraction of Rotating Clouds: Formation of Self-similarly Collapsing Disks , 1997 .

[25]  W. Herbst,et al.  Rotation Periods of Stars in the Orion Nebula Cluster: The Bimodal Distribution , 1996 .

[26]  N. Morrell,et al.  The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars , 1995 .

[27]  K. M. Merrill,et al.  Angular Momentum Regulation in Low-Mass Young Stars Surrounded by Accretion Disks , 1993 .

[28]  John R. Stauffer,et al.  The evolution of angular momentum among zero-age main-sequence solar-type stars , 1993 .

[29]  W. Herbst,et al.  Rotation Periods of T Tauri Stars in the Orion Nebula Cluster: A Bimodal Frequency Distribution , 1992 .

[30]  S. Cranmer,et al.  Model atmospheres for rotating B stars , 1991 .

[31]  K. Macgregor,et al.  Rotational Evolution of Solar-Type Stars. I. Main-Sequence Evolution , 1991 .

[32]  A. Koenigl.  Disk accretion onto magnetic T Tauri stars , 1991 .

[33]  M. Pinsonneault,et al.  Rotation of low-mass stars - A new probe of stellar evolution , 1990 .

[34]  D. F. Gray.  The rotational break for G giants , 1989 .

[35]  L. Prévot,et al.  Complementary astrophysical data for Hipparcos stars. (1) Astrophysical fundamental parameters of early-type Hipparcos stars. (2) Radial velocities of southern late-type Hipparcos stars. Profile of two key programmes. , 1989 .

[36]  S. Adelman.  Elemental abundance analyses with Coadded Dominion Astrophysical Observatory spectrograms. III: The superficially normal standard stars Theta Leonis, Tau Herculis and Omicron Pegasi , 1988 .

[37]  B. Shustov.  Protostars and Planets II , 1987 .

[38]  W. Jefferys,et al.  GaussFit—A system for least squares and robust estimation , 1987 .

[39]  P. J. Green,et al.  Density Estimation for Statistics and Data Analysis , 1987 .

[40]  S. Morton,et al.  The angular momentum problem during star formation Magnetically linked, aligned rotators. I - an exact, time-dependent solution , 1985 .

[41]  S. Morton,et al.  The Angular Momentum Problem during Star Formation - Magnetically Linked Aligned Rotators - Part Two - Results , 1985 .

[42]  R. Pudritz.  Star formation in rotating, magnetized molecular disks , 1984 .

[43]  L. Hartmann,et al.  Rotational velocities of low-mass stars in the Hyades , 1984 .

[44]  Philip J. Davis,et al.  Chapter 6 – Automatic Integration , 1984 .

[45]  E. Boehm-Vitense.  Effective temperatures of A and F stars. , 1982 .

[46]  B. Guthrie.  The bimodal distribution of rotational velocities of late B-type stars in galactic clusters. , 1982 .

[47]  J. Toomre,et al.  Stellar convection theory. III - Dynamical coupling of the two convection zones in A-type stars by penetrative motions , 1981 .

[48]  A. Endal,et al.  Rotation in solar-type stars. I. Evolutionary models for the spin-down of the sun , 1981 .

[49]  D. Lamb,et al.  Fundamental problems in the theory of stellar evolution; Proceedings of the Symposium, Kyoto, Japan, July 22-25, 1980 , 1981 .

[50]  S. Wolff.  Duplicity of late B-type stars , 1978 .

[51]  G. Sonneborn,et al.  Some effects of rotation on the spectra of upper-main-sequence stars. , 1977 .

[52]  D. F. Gray,et al.  The Observation and Analysis of Stellar Photospheres , 2021 .

[53]  P. B. Boyce,et al.  A system of standard stars for rotational velocity determinations , 1975 .

[54]  L. Lucy.  An iterative technique for the rectification of observed distributions , 1974 .

[55]  C. Jaschek,et al.  A study of the bright A stars. II. Discussion of spectral types, colors, and rotation. , 1970 .

[56]  T. R. Stoeckley.  Distribution of Rotational Velocities in Be Stars , 1968 .

[57]  R. P. Kraft,et al.  STUDIES OF STELLAR ROTATION. V. THE DEPENDENCE OF ROTATION ON AGE AMONG SOLAR-TYPE STARS. , 1967 .

[58]  J. M. Fletcher,et al.  Seventh catalogue of the orbital elements of spectroscopic binary systems , 1967 .

[59]  R. C. Cameron,et al.  The magnetic and related stars , 1967 .

[60]  O. C. Wilson.  STELLAR CONVECTION ZONES, CHROMOSPHERES, AND ROTATION , 1966 .

[61]  S. Chandrasekhar,et al.  On the Integral Equation Governing the Distribution of the True and the Apparent Rotational Velocities of Stars. , 1950 .

[62]  Bartlett Ms.  The use of transformations. , 1947 .