* Astronomy

Blobrana · L

RE: SZ Camelopardalis

Blobrana · L

Title: Asiago eclipsing binaries program. IV. SZ Camelopardalis, a beta Cephei pulsator in a quadruple, eclipsing system
Authors: E. Tamajo, U. Munari, A. Siviero, L. Tomasella, S. Dallaporta

We present a spectroscopic and photometric analysis of the multiple system and early-type eclipsing binary SZ Cam (O9IV + B0.5V), which consists of an eclipsing SB2 pair of orbital period P=2.7 days in a long orbit (about 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 CCD photometry to obtain an orbital solution. Our photometry revealed the presence of a beta 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.

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Blobrana · L

Title: The O-type eclipsing binary SZ Cam revisited
Authors: Pavel Mayer, Horst Drechsel, Jií Kubát, Miroslav lechta

We analyse new spectra of the multiple system SZ Cam because previous studies found different values of the primary radial velocity amplitude. The older solutions of light curves also have different ratios of secondary to primary luminosity as inferred from the observed equivalent widths of spectral lines. We therefore reanalyse the light curves of the eclipsing pair. Only the light curve derived by Wesselink has a solution that agrees with the observed equivalent width ratio. The resulting parameters of the binary are discussed. Masses of M_1=16.6 and M_2=11.9 solar masses, and radii R_1=9.4 and R_2=5.4 solar radii are derived. We point out that radial velocities measured with the CCF method can be misleading when the method is applied to multiple systems with complex line blends. New radial velocities are also obtained for the visual component ADS 2984 A (HD 25639).

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