Magnetic activity and evolution of Algol-type stars - II

Yerli, Sinan Kaan
Muslimov, A G
We examine the possibility of probing dynamo action in mass-losing stars, components of Algol-type binaries, Our analysis is based on the calculation of nonconservative evolution of these systems, We model the systems U Sge and beta Per where the more massive companion fills its Roche lobe at the main sequence (case AB) and where it has a small helium core (early case B) respectively, We show that to maintain evolution of these systems at the late stages which are presumably driven by stellar 'magnetic braking', an efficient mechanism for producing large-scale surface magnetic fields in the donor star is needed. We discuss the relevance of dynamo operation in the donor star to the accelerated mass transfer during the late stages of evolution of Algol-type binaries. We suggest that the observed X-ray activity in Algol-type systems may be a good indicator of their evolutionary status and internal structure of the mass-losing stellar components.


Radial motion of highly conducting sphere in magnetic field
Gurcan, OD; Mirnov, VV; Ucer, D (2000-05-01)
Radial motion of a highly conducting sphere in external magnetic field is considered. It both perturbs the external magnetic field and generates an electric field. Exact analytic solution has been obtained previously for a uniformly expanding sphere. In the present paper a new exact solution is derived which is valid not only for expansion but for contraction as well. It allows us to calculate analytically the total electromagnetic energy irradiated by the sphere involved in periodical radial motion with ar...
Rotational evolution of intermediate mass stars with OPAL opacities: Mass of the convective core
Kiziloglu, N; Civelek, R (1996-03-01)
Theoretical evolutionary models for intermediate mass rotating stars were obtained by the use of OPAL opacities to see the effect on the internal structure and primarily on the mass of the convective core. The new ZAMS positions of rotating intermediate mass stars in the HR diagram were found to be above those of rotating stars obtained by using Cox & Stewart opacities. Rotation led to a reduction in the central value of the radiative temperature gradient and hence the masses of convective cores on the ZAMS...
Magnetic Resonance Signal Analysis in Inhomogenous Magnetic Fields
Arpinar, V. E.; Eyüboğlu, Behçet Murat (2009-09-12)
Nuclear Magnetic Resonance (NMR) systems with inhomogenous main magnetic fields have been satisfactorily used to explore material properties. So that, imaging of biological tissues using Magnetic Resonance Imaging (MRI) systems with inhomogenous main magnetic fields could be explored. In this work, magnetic resonance (MR) signal deviation due to inhomogeneity in the main magnetic field of a MRI system is investigated. This analysis gives the understanding of the effect of inhomogeneity in magnetic field to ...
Electrical impedance tomography using the magnetic field generated by injected currents
Birgul, O; Ider, YZ (1996-11-03)
In 2D EIT imaging, the internal distribution of the injected currents generate a magnetic field in the imaging region which can be measured by magnetic resonance imaging techniques. This magnetic field is perpendicular to the imaging region on the imaging region and it can be used in reconstructing the conductivity distribution inside the imaging region. For this purpose, internal current distribution is found using the finite element method. The magnetic fields due to this current is found using Biot-Savar...
Frequency Resolved Spectroscopy of XB 1323-619 and EXO 0748-676
Balman, Şölen (2009-09-11)
We present the frequency resolved energy spectra (FRS) of the low-mass X-ray binary dipper XB 1323-619 and EXO 0748-676 using archival XMM-Newton observations. The FRS of XB 1323-619 is well described by a single blackbody component with kT in a range 1.2-1.6 keV. We attribute this to an existing boundary layer, the likely source of the soft emission, supported by radiation pressure. We detect a different form of FRS for the frequency ranges 0.9-6 Hz and 8-30 Hz which is modeled best with a power law and a ...
Citation Formats
M. SARNA, S. K. Yerli, and A. G. Muslimov, “Magnetic activity and evolution of Algol-type stars - II,” MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, pp. 760–768, 1998, Accessed: 00, 2020. [Online]. Available: