Beta Cephei stars and slowly pulsating B stars

Variability is common among B stars. The Beta Cephei stars and the slowly pulsating B stars are two classes of well established B-type pulsators amongst them and are found in the upper part of the main-sequence (Fig. 1). Their pulsations are driven by the opacity mechanism acting on the Z-bump.

HR diagram with all classes of pulsating stars    Position of the beta Cephei stars and the Slowly Pulsating B stars in the HR diagram

Fig. 1. Left: Location of the main classes of variable stars in a theoretical Hertzsprung-Russell diagram. The beta Cephei stars and the Slowly Pulsating B stars are respectively given in turquoise and green (figure taken from ESA, 2000, "Eddington - A mission to map stellar evolution and to find habitable planets, Results of the Assessment Study")
Right: The positions of the confirmed (full symbols) and candidate (open symbols) beta Cephei stars (circles) and Slowly Pulsating B stars (squares) in the main-sequence. We also show the ZAMS (lower dotted lines), the TAMS (upper dotted lines) and the theoretical instability strips for Z = 0.020 for modes with pulsation degree l < 2, computed using the OPAL opacities for stellar models with X= 0.70 for which effects of rotation and convective overshooting were not taken into account (Pamyatnykh A.A., 1999, Acta Astronomica, 49, 119).   

Slowly pulsating B stars are:

Beta Cephei stars are:

All the references used in the different tables can be found here.

* Note that we list only stars for which Geneva photometry is available to enable a homogeneous determination of
   the stellar parameters!  

Any additions, corrections or suggestions are always welcome!
Anyone interested in the asteroseismology of beta Cephei stars and/or slowly pulsating B stars is encouraged to contact us.

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Last update: 28/01/2004