A photometric-spectroscopic analysis and the evolutionary status of the Algol-type binary U Coronae Borealis

Download
2003-07-11
Yerli, Sinan Kaan
Zola, S
Smith, RC
Tovmassian, G
The prime purposes of this study are to obtain reliable orbital parameters for the Algol-type binary U Coronae Borealis (U CrB) and to explain the evolutionary status of this system. All observations of the primary star's radial velocity are consistent with the value K(1) = 58.6 +/- 2.0 km s(-1). Measurements of the radial velocity of the secondary component give K(2) = 185.2 +/- 5.0 km s(-1). Using the photometrically determined inclination of 78.7 +/- 0.3, the masses of the two stars are therefore deduced to be 4.74 +/- 0.28 and 1.46 +/- 0.06 M. for the primary and secondary components, respectively. Using all available observations, we discuss the origin and evolution of the close binary system U CrB. We derive the restrictions concerning masses and period from a general network of calculations of medium mass close binary evolution. Detailed models are calculated within the derived ranges, giving the most likely initial system parameters as and P(i) = 1.4 d. It turns out that the interactive evolution up to the present stage has been non-conservative. During its evolution, U CrB has lost about 14 per cent of its initial total mass (DeltaM similar to 1 M.) and around 18 per cent of its initial total angular momentum. We also examine the possibility of probing dynamo action in the mass-losing component of U CrB. We point out that, in order to maintain the evolution of U CrB in its later stages, which is presumably driven by stellar 'magnetic braking', an efficient mechanism for producing large-scale surface magnetic fields in the donor star is required. We suggest that observed X-ray activity in U CrB may be a good indicator of its evolutionary status and the internal structure of the mass-losing component.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

Suggestions

A Study on W Ursae Majoris-Type Systems Recognised by the ROTSE-IIId Experiment
Coker, D.; ÖZDEMİR, SACİT; YEŞİLYAPRAK, Cahit; Yerli, Sinan Kaan; AKSAKER, NAZIM; Gucsav, B. B. (Cambridge University Press (CUP), 2013-01-24)
We present a study on characterising the light curves of W UMa-type systems gathered from the archive containing 5 years of data observed with the Robotic Optical Transient Search Experiment Telescope (ROTSE-IIId) located in Turkey. A sample of 45 W UMa-type systems was studied on the basis of Fourier decomposition of light curves and some basic geometrical parameters, namely degree of contact (f), mass ratio (q), and orbital inclination (i), as approximated values for these systems were determined. Moreove...
Modelling the oscillating star V1162 Ori
Civelek, R; Kiziloglu, N; Kirbiyik, H (EDP Sciences, 2003-12-01)
Evolutionary stellar models of V1162 Ori, with the latest observations of a multiperiodic delta Scuti star, have been calculated theoretically and compared with the observations. Theoretical models representative of the star indicate that it is at an advanced stage of its main-sequence evolution. Calculations have been made for two different masses, 1.80 and 1.82 M-., at different rotational speeds. Rotation was treated as a perturbation and only the first-order effect was considered. The evolutionary model...
A STUDY OF THE LOW-MASS X-RAY BINARY DIP SOURCES XB 1916-053, XB 1323-619, X 1624-490 AND 4U 1746-371 OBSERVED WITH INTEGRAL
Balman, Şölen (IOP Publishing, 2009-07-01)
We detect dipping activity/modulations in the light curve of the four low-mass X-ray binaries in the 3-10 keV and 20-40 keV energy ranges. The spectral parameters derived from the fits to the International Gamma-Ray Astrophysics Laboratory data are consistent with hot coronal structures in these systems where we find a range of plasma temperatures 3.0-224.9 keV. The unabsorbed X-ray to soft gamma-ray fluxes between 4 keV and 200 keV are 5.9 x 10(-10) erg s(-1) cm(-2) for XB 1916-053, 3.3 x 10(-10) erg s(-1)...
A Suzaku X-ray study of the mixed-morphology supernova remnant Kes 69 and searching for its gamma-ray counterpart
Sezer, A.; Ergin, Tülün; Yamazaki, R.; Ohira, Y.; Cesur, N. (Oxford University Press (OUP), 2018-11-01)
Kes 69 is a mixed-morphology (MM) supernova remnant (SNR) that is known to be interacting with molecular clouds based on 1720 MHz hydroxyl (OH) maser emission observations in the northeastern and southeastern regions. We present an investigation of Kes 69 using similar to 67 ks Suzaku observation. The X-ray spectrum of the whole SNR is well fitted by a non-equilibrium ionization model with an electron temperature of kT(e) similar to 2.5 keV, ionization time-scale of tau similar to 4.1 x 10(10) cm(-3) s and ...
Investigations of pulsational properties and evolution of propagation diagram in some delta Scuti star models
Kiziloglu, N; Kirbiyik, H; Civelek, R (World Scientific Pub Co Pte Lt, 2003-07-01)
An investigation on the subject of evolution of propagation diagrams and obtaining the theoretical frequency spectrum of some delta Scuti star models with masses around 2 M-circle dot has been presented. The variations of some eigenfunctions throughout the star, the variation of omega(2) with logT(e) and the distribution of nodes of eigenfunctions of some modes along with the evolution of the star have been plotted and examined. For the models at the ZAMS phase, pure acoustic modes in the outer stellar laye...
Citation Formats
S. K. Yerli, S. Zola, R. Smith, and G. Tovmassian, “A photometric-spectroscopic analysis and the evolutionary status of the Algol-type binary U Coronae Borealis,” MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, pp. 1349–1360, 2003, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/38113.