Radial and nonradial oscillations in stars with gravitational potential perturbation

Özel, Nesibe
In this study, the linear adiabatic radial and nonradial oscillations of evolutionary stellar model with 1.80M©, representing the star VI 162 Ori, has been investigated. The already working oscillation program with Cowling approximation, which ig nores the Eulerian perturbation in gravitational potential, has been modified to carry out the radial and nonradial linear adiabatic perturbations of stellar mod els using the Eulerian perturbation in gravitational potential. The new set of equations were solved without Cowling approximation. In the last part, the calculated oscillation frequencies with and without Cowl ing approximation have been compared with the observed frequency spectrum of the variable 5-Scuti star V1162 Ori.


Evolution Of Rotating Low Mass Stars With Angular-Momentum Loss
KIZILOGLU, N (1991-03-01)
The evolutionary behavior of rotating low mass stars has been investigated with angular momentum loss by the magnetic stellar wind through the pre-main sequence and on the zero age main sequence phases. As the stars contract toward the zero age main sequence, angular momentum is removed from the convective envelope under the assumption that initially only the convective envelope is spun down in low mass stars. It is obtained that most of the angular momentum loss occurs prior to reaching the zero age main s...
Radial and nonradial oscillations of 44 Tauri
Civelek, R; Kiziloglu, N; Kirbiyik, H (American Astronomical Society, 2001-10-01)
Evolutionary stellar models of 44 Tauri, a multiperiodic delta Scuti star, have been developed theoretically and compared with earlier observational reports. The models depict 44 Tau at the hydrogen-shell-burning stage, when it is in radiative equilibrium with a very thin surface convective layer. Using the models, we performed calculations to obtain radial and nonradial adiabatic oscillation frequencies, and the equations were treated linearly. The results showed that the radial fundamental (6.899 cycles d...
Hamiltonian for a particle in a magnetic field on a curved surface in orthogonal curvilinear coordinates
Shikakhwa, M. S.; Chair, N. (2016-08-19)
The Schrodinger Hamiltonian of a spin-less particle as well as the Pauli Hamiltonian with spin-orbit coupling included of a spin one-half particle in electromagnetic fields that are confined to a curved surface embedded in a three-dimensional space spanned by a general Orthogonal Curvilinear Coordinate are constructed. A new approach, based on the physical argument that upon squeezing the particle to the surface by a potential, then it is the physical gauge-covariant kinematical momentum operator (velocity ...
Magnetic activity and evolution of Algol-type stars - II
SARNA, MAREK; Yerli, Sinan Kaan; Muslimov, A G (1998-07-01)
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 brak...
Critical evolution of hot van der Waals droplets
Kondratyev, VN; Lutz, HO; Ayik, S (1997-05-08)
The dynamical evolution and fragmentation of a hot finite van der Waals system is investigated in a classical molecular dynamics approach. It is demonstrated that, under certain conditions determined mainly by the initial deposited energy, the fragmentation of rare-atom clusters exhibit a critical behavior. This behavior leaves its signatures in the mass distributions and the conditional moments, as well as the scaled factorial moments of the produced fragments. The connection between the observed critical ...
Citation Formats
N. Özel, “Radial and nonradial oscillations in stars with gravitational potential perturbation,” M.S. - Master of Science, Middle East Technical University, 2003.