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Paper: Rotation of Achernar and Regulus through Fourier Transform Analysis of High Resolution Spectra
Volume: 361, Active OB-Stars: Laboratories For Stellar and Circumstellar Physics
Page: 425
Authors: Gavrilovic, N.; Jankov, S.
Abstract: Projected rotational velocity parameter Ve sin i for selected stars has been determined using high-resolution spectroscopic observations from UVES and ELODIE databases and FEROS spectra. Applying the Fourier Transform Method this parameter can be precisely measured since (under classical approximations) the position of first minimum is determined only by rotational broadening, providing an estimate which is fairly insensitive to the assumptions about intrinsic line profile, micro and macro turbulence, eventually pulsational broadening and emission from circumstellar envelope, which is crucial for accurate determination of Ve sin i in Be stars (Neiner et al. 2002). We study in particular Achernar (α Eri) and Regulus (α Leo A), two stars in which the extreme oblateness has been recently discovered by interferometry. Since the Fourier Transform Method allows the detection of deviations from solid body rotation, rotational oblateness and gravity darkening (Reiners 2003), we discuss the extent to which our measurements reflect the actual projected equatorial rotation velocities.
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