The Acoustic Cut-Off Frequency of roAp Stars
نویسندگان
چکیده
منابع مشابه
Abundance analyses of roAp stars
In this sixth paper in a sequence on abundance analyses of roAp stars we present the results for two further members of this group, which are fairly similar and have only a small magnetic field. The analysis of 10 Aql and HD 122970 did not require, for the first time in this long term project, the development of tools and hence was rather straight-forward. We reanalyzed Sm, Eu and Gd in HD 2039...
متن کاملSome recent results for the roAp stars
Three topics are discussed: 1) Photometric observations of the rapidly oscillating Ap stars have shown that the pulsation amplitude drops dramatically as a function of wavelength from the blue to the red. A theoretical derivation, plus modelling, indicate s that this is because the vertical wavelength of the pulsation mode is short compared to the scale height of the atmosphere; in fact, it ind...
متن کاملOptimal High Frequency Cut-off in SWAN Wave Model
This study investigates the importance of selecting an appropriate cut-off frequency in the SWAN model when it is applied to areas with limited fetches. In SWAN, the cut-off frequency is a constant value set by user in the model, and its appropriate selection plays an important role in the accuracy and optimization of the wave model; very high value increases the computational cost and might le...
متن کاملModeling the Cut-off Frequency of Acoustic Signal with an Adaptative Neuro-Fuzzy Inference System (ANFIS)
An Adaptative Neuro-Fuzzy Inference System (ANFIS), new flexible tool, is applied to predict the cut-off frequencies of the symmetric and the anti-symmetric circumferential waves (Si and Ai, i=1,2) propagating around an elastic aluminum cylindrical shell of various radius ratio b/a (a: outer radius and b: inner radius). The time-frequency of WignerVille and the proper modes theory are used in t...
متن کاملNon-axisymmetric oscillations of roAp stars
We calculate the effect of a strong dipole magnetic field on non-axisymmetric oscillations for roAp stars, with a typical range of photospheric magnetic fields Bp [0.5-1.5] kG. As Dziembowski & Goode (1996), we find that the oscillations are strongly affected by such magnetic fields in two different ways. The first one concerns the stability of modes, which are damped due to dissipation by Alfv...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1998
ISSN: 0074-1809
DOI: 10.1017/s0074180900238801