Mode identification of pulsating stars from line-profile variations with the moment method: a more accurate discriminant.
We present a new discriminant for the analysis of line-profile variations in pulsating stars with the moment method. This discriminant enables identification of the wavenumbers (l,m) of non-radial modes and at the same time provides estimates of the amplitude of the pulsation, the inclination angle of the star, its rotation velocity, and the width of the intrinsic line profile. Our new discriminant is based upon all the amplitudes in the first three moments of the line profiles and therefore uses significantly more information than our previously proposed discriminant (see Aerts et al. 1992). The new discriminant is tested by means of theoretically generated profiles and turns out to be a more accurate identifier than the previous one, especially in the case of sectoral modes. For multiperiodic stars, the identification of the different modes now becomes easier, while we were only able to unambiguously identify the main mode with the formalism presented in Mathias et al. (1994a). We give the results of the new discriminant for the βCephei star 12Lacertae, for which six different modes are known.
Astronomy and Astrophysics
- Pub Date:
- October 1996
- LINE: PROFILES;
- STARS: OSCILLATIONS;
- STARS: INDIVIDUAL: 12 LACERTAE