Asiago eclipsing binaries program IV. SZ Camelopardalis, a β Cephei pulsator in a quadruple, eclipsing system^⋆

E. Tamajo^1,2, U. Munari², A. Siviero³, L. Tomasella² and S. Dallaporta⁴

¹ Department of Physics, University of Zagreb, Bijenička cesta 32, 10000 Zagreb, Croatia
e-mail: etamajo@phy.hr
² INAF Astronomical Observatory of Padova, 36012 Asiago (VI), Italy
³ Department of Astronomy, University of Padova, 35122 Padova (PD), Italy
⁴ ANS Collaboration, c/o Osservatorio Astronomico, via dell’Osservatorio 8, 36012 Asiago (VI), Italy

Received: 5 August 2011
Accepted: 16 January 2012

Abstract

We present a spectroscopic and photometric analysis of the multiple system and early-type eclipsing binary SZ Cam (O9 IV + B0.5 V), which consists of an eclipsing SB2 pair of orbital period P = 2.7 days in a long orbit (~55 yrs) around a non-eclipsing SB1 pair of orbital period P = 2.8 days. We have reconstructed the spectra of the individual components of SZ Cam from the observed composite spectra using the technique of spectral disentangling. We used them together with extensive and accurate BVI_C CCD photometry to obtain an orbital solution. Our photometry revealed the presence of a β Cep variable in the SZ Cam hierarchical system, probably located within the non-eclipsing SB1 pair. The pulsation period is (0.33265  ±  0.00005) days and the observed total amplitude in the B band is (0.0105  ±  0.0005) mag. NLTE analysis of the disentangled spectra provided atmospheric parameters for all three components, consistent with those derived from orbital solution.