Pulsational mode typing in line profile variables. V. Multimodes and "moving shells" in nu Eridani and other beta Cephei stars.
Abstract
An analysis of 31 high-resolution Reticon observations of the Si III 4567 A line reveals that most of its variations in shape are a result of nonlinear hydrodynamic processes that remain in phase with the dominant fourth (radial velocity-producing) mode. Line profile analysis shows that this fourth mode is compatible only with radial pulsation and incompatible with any nonradial pulsation mode, including any with m = 0. When the hydrodynamical effects are nearly absent from the profiles at certain times during the cycle, only one of the three nonradial modes (-m = l) is found to be of importance in describing the residual profile variations; this is in agreement with the star's presumed equator-on aspect and with energy equipartition for the triplet-modes. Several conditions imposed by the spectroscopic and photometric amplitudes of the triplet modes require the identification l = 2, and m = -2, -1, and 0.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1983
- DOI:
- 10.1086/160679
- Bibcode:
- 1983ApJ...265..338S
- Keywords:
-
- Cepheid Variables;
- Line Spectra;
- Stellar Oscillations;
- Stellar Spectra;
- Radial Velocity;
- Shock Waves;
- Signal To Noise Ratios;
- Stellar Atmospheres;
- Astrophysics