Constant eclipsing binary in the instability strip

WOS: 000349503400011The eclipsing binary OO Peg consist of two late-A type stars in circular orbit with a period of 2.985 days. I use the high-resolution spectroscopic and extensive light curves from the ASAS and Hipparcos survey to measure the physical properties of the system. Previous attempts to model the light and radial velocity curves of the system have met with limited success, primarily because of the lack of a accurate photometric data. The system shows no signs of stellar activity, it is slowly rotating, has not been detected period changes, and there is no pulsational signs in the photometric data. I show the location of the components in effective temperature vs. luminosity diagram compared to the instability region limits established from eclipsing binary components. While more than 25 system have been plotted to diagram, about six single stars and OO Peg components do not show any pulsational frequencies. They are apparently constant stars lie within the pulsation instability region. I speculate as to the possible causes of this picture. (C) 2014 Elsevier B.V. All rights reserved.Italian Minister dell'Istruzione, Universita e Ricerca (MIUR); Turkish Scientific and Technology CouncilTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [114F354]; EBILTEM Ege University Research CenterEge University [2013/BIL/018]This work was partially supported by the Italian Minister dell'Istruzione, Universita e Ricerca (MIUR). This study is supported by Turkish Scientific and Technology Council under project number 114F354. We thank to EBILTEM Ege University Research Center for a partial support with project number 2013/BIL/018. The following internet-based resources were used in research for this paper: the NASA Astrophysics Data System; the SIMBAD database operated at CDS, Strasbourg, France; and the arXiv scientific paper preprint service operated by Cornell University