Variable stars in Kappa Crucis

A. M. ORSATTI,; M. M. VERGNE; C. FEINSTEIN; R.E.MARTINEZ

Revista de la Asociacion Argentina de Astronomia

Año: 2008 vol. 51

1669-9521

We present a polarimetric study of Beta Cep stars located in the open cluster NGC 4755, also known as Kappa Crucis. These are pulsating stars of spectral types O - B2 V - III with very short periods (3 to 6 hours) and small amplitudes (0.1 to 0.3 mag). Beta Cep are massive  objects (10 to 20 Mo), located along a narrow band in the HR diagram, where it can be found other objects ending with the Hidrogen burn in their core. Many of them pulse in a non-radial way . The polarimetric observations in the UBVRI bands were obtained with the Torino photopolarimeter and the  Jorge Sahade 2.15m telescopeat CASLEO (San Juan, Argentina).