Line-profile variations of non-radial adiabatic pulsations of rotating stars. III. On the alleged misidentification of tesseral modes.
Abstract
We use a model of a non-radially, adiabatically pulsating rotating star to generate time series of absorption line profiles. We analyse the spectral time series of a tesseral mode with pulsation parameters l=2 and m=-1, to obtain amplitude and phase diagrams as a function of position in the line profile. We investigate whether the phase diagrams can be used to identify the pulsation parameters l and |m| of this mode. As opposed to the findings of Reid & Aerts (1993A&A...279L..25R), we find that the effects of the Coriolis force do not hinder the identification of the degree l of the pulsation mode, but that the exact value of i=90deg that they used does. We show that for an inclination angle just slightly different from 90deg the chances for an erroneous identification of the degree l of the l=2, m=-1 pulsation mode, by means of a spectroscopical phase diagram, are very small. We also discuss the interpretation of observed line-profile variations in the Be star η Cen, where a tesseral mode with l=7 and m=|6| might be present.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1997
- Bibcode:
- 1997A&A...317..742T
- Keywords:
-
- STARS: EARLY-TYPE;
- OSCILLATIONS;
- ROTATION;
- LINE: PROFILES;
- STARS INDIVIDUAL: {ETA} CEN