2014A&A...569A.118A


Query : 2014A&A...569A.118A

2014A&A...569A.118A - Astronomy and Astrophysics, volume 569A, 118-118 (2014/9-1)

On the use of the Fourier transform to determine the projected rotational velocity of line-profile variable B stars.

AERTS C., SIMON-DIAZ S., GROOT P.J. and DEGROOTE P.

Abstract (from CDS):

The Fourier transform method is a popular tool for deriving the rotational velocities of stars from their spectral line profiles. However, its domain of validity does not include line-profile variables with time-dependent profiles. We investigate the performance of the method for such cases, by interpreting the line-profile variations of spotted B stars and of pulsating B stars, as if their spectral lines were caused by uniform surface rotation along with macroturbulence. We perform time-series analysis and harmonic least-squares fitting of various line diagnostics and of the outcome of several implementations of the Fourier transform method. We find that the projected rotational velocities derived from the Fourier transform vary appreciably during the pulsation cycle whenever the pulsational and rotational velocity fields have similar magnitudes. The macroturbulent velocities derived while ignoring the pulsations can vary by tens of km/s during the pulsation cycle. The temporal behaviour of the deduced rotational and macroturbulent velocities are in antiphase with each other. The rotational velocity is in phase with the second moment of the line profiles. The application of the Fourier method to stars with considerable pulsational line broadening may lead to an appreciable spread in the values of the rotation velocity, and, by implication, of the deduced value of the macroturbulence. These two quantities should therefore not be derived from single snapshot spectra if the aim is to use them as a solid diagnostic evaluating stellar evolution models of slow-to-moderate rotators.

Abstract Copyright:

Journal keyword(s): line: profiles - techniques: spectroscopic - stars: massive - stars: rotation - stars: oscillations - stars: evolution

Simbad objects: 7

goto Full paper

goto View the references in ADS

Number of rows : 7
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 * del Cet bC* 02 39 28.95579 +00 19 42.6345 2.97 3.85 4.07     B2IV 371 0
2 * ksi01 CMa bC* 06 31 51.3663578 -23 25 06.318090 3.10 4.09 4.33 4.45 4.72 B0.7IV 310 0
3 * omi Vel Pu* 08 40 17.5855320 -52 55 18.800233 2.8 3.44 3.63     B3/5(V) 168 1
4 HD 105382 Be* 12 08 05.2222663992 -50 39 40.575451536 3.65 4.32 4.47 4.53 4.70 B5V 162 0
5 * bet Cru bC* 12 47 43.26877 -59 41 19.5792 0.03 1.02 1.25 1.38 1.64 B1IV 333 0
6 HR 5543 ** 14 52 51.0737484 -37 48 11.386959 4.11 4.855 5.015     B7IIIp 117 0
7 HD 181558 Pu* 19 21 37.1135468520 -19 14 04.045448508 5.65 6.16 6.26     B5III 64 0

To bookmark this query, right click on this link: simbad:objects in 2014A&A...569A.118A and select 'bookmark this link' or equivalent in the popup menu


2022.12.07-03:48:52

© Université de Strasbourg/CNRS

    • Contact