Effet de l’assombrissement centre-bord sur les raies spectrales:Cas typique des étoiles de type G
- . Revue CNRST, Sciences et Techniques/Sciences Naturelles et Appliquées. , 44 (2) : 193-216
Résumé
We present the impact of center-to-limb darkening (𝜀𝑖) on spectral line profiles of G-type stars through systematic analysis of cross-correlation function broadening. Using solar-type stellar spectra, we examine how center-to-limb darkening coefficients affect the measured full width at half maximum (FWHMCC) and derived rotational velocities (Vbroad). Our analysis employs the darkening coefficients from (Claret, 2000) and samples 19 rotational velocities from 0 to 100 km/s to optimize coverage of the observed stellar rotational ranges for calibration. We demonstrate that center- to-limb darkening variations induce systematic changes in measurements, with particularly pronounced effects for slow rotators where macroturbulence contributions (2-4 km/s) become dominant. The broadening parameter shows significant correlation with the darkening coefficient varying by 4.4 km/s (44.8%) over the studied range. These results highlight the critical importance of accurate center-to-limb darkening modeling for precise stellar rotation measurements in spectroscopic surveys of G-type stars.
Mots-clés
Line broadening – Center-to-limb darkening – G-type stars