scholarly journals Confirming the oblique rotator model for the extremely slowly rotating O8f?p star HD 108

2017 ◽  
Vol 468 (4) ◽  
pp. 3985-3992 ◽  
Author(s):  
M. Shultz ◽  
G. A. Wade
Keyword(s):  
Rotator Model ◽  
Oblique Rotator

Discussion of the Oblique Rotator Model Cases Of 108 Aqr and x Serp.

1976 ◽  
Vol 32 ◽  
pp. 577-588
Author(s):  
C. Mégessier ◽  
V. Khokhlova ◽  
T. Ryabchikova
Keyword(s):  
Mathematical Formulation ◽  
The Other ◽  
Rotator Model ◽  
Oblique Rotator ◽  
First Results

My talk will be on the oblique rotator model which was first proposed by Stibbs (1950), and since received success and further developments. I shall present two different attempts at describing a star according to this model and the first results obtained in the framework of a Russian-French collaboration in order to test the precision of the two methods. The aim is to give the best possible representation of the element distributions on the Ap stellar surfaces. The first method is the mathematical formulation proposed by Deutsch (1958-1970) and applied by Deutsch (1958) to HD 125248, by Pyper (1969) to α2CVn and by Mégessier (1975) to 108 Aqr. The other one was proposed by Khokhlova (1974) and used by her group.

Peculiarity Parameters

1976 ◽  
Vol 32 ◽  
pp. 233-254
Author(s):  
H. M. Maitzen
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Theoretical Work ◽  
Observational Evidence ◽  
Rotator Model ◽  
Peculiar Behaviour ◽  
Field Spectrum ◽  
Oblique Rotator ◽  
Ap Stars ◽  
The Way

Ap stars are peculiar in many aspects. During this century astronomers have been trying to collect data about these and have found a confusing variety of peculiar behaviour even from star to star that Struve stated in 1942 that at least we know that these phenomena are not supernatural. A real push to start deeper theoretical work on Ap stars was given by an additional observational evidence, namely the discovery of magnetic fields on these stars by Babcock (1947). This originated the concept that magnetic fields are the cause for spectroscopic and photometric peculiarities. Great leaps for the astronomical mankind were the Oblique Rotator model by Stibbs (1950) and Deutsch (1954), which by the way provided mathematical tools for the later handling pulsar geometries, anti the discovery of phase coincidence of the extrema of magnetic field, spectrum and photometric variations (e.g. Jarzebowski, 1960).

scholarly journals An Oblique Rotator Model for DQ Herculis

1974 ◽  
Vol 166 (1) ◽  
pp. 113-121 ◽  
Author(s):  
G. T. Bath ◽  
W. D. Evans ◽  
J. E. Pringle
Keyword(s):  
Rotator Model ◽  
Oblique Rotator

scholarly journals Magnetic Braking and the Oblique Rotator Model

1970 ◽  
Vol 4 ◽  
pp. 269-273
Author(s):  
L. Mestel ◽  
C. S. Selley
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Stellar Wind ◽  
Rotation Axis ◽  
Dynamical Evolution ◽  
Magnetic Star ◽  
Rotator Model ◽  
Oblique Rotator ◽  
Magnetic Braking

This work investigates the dynamical evolution of a rotating magnetic star which drives a stellar wind. The basic magnetic field of the star is supposed symmetric about an axis, which is inclined at an angle X to the rotation axis k (Figure 1). We adopt the familiar equations of an inviscid perfectly conducting gas. In a steady state, the velocity as seen in a frame rotating with the star is taken as

scholarly journals Magnetic Field and Silicon diffusion in Bp-Si Stars

1988 ◽  
Vol 132 ◽  
pp. 329-332
Author(s):  
C. Mégessier ◽  
T. Lanz ◽  
J. D. Landstreet
Keyword(s):  
Magnetic Field ◽  
Zeeman Splitting ◽  
Open Clusters ◽  
Stellar Surface ◽  
Line Profiles ◽  
Abundance Distribution ◽  
Rotator Model ◽  
Oblique Rotator ◽  
Silicon Diffusion

SiII lines of magnetic Bp-Si stars in open clusters have been observed with the CAT (ESO) in order to get a mapping of the Silicon abundance distribution over the stellar surface, in the frame of the oblique rotator model. We point out the influence of the Zeeman splitting and of the abundance inhomogeneities on the line profiles.

Sub-rotation and Super-rotation in Pulsar Magnetospheres

1981 ◽  
Vol 34 (1) ◽  
pp. 97
Author(s):  
RR Burman
Keyword(s):  
Stellar Surface ◽  
Light Cylinder ◽  
Rotator Model ◽  
Oblique Rotator

For magnetospheric species that are nonrelativistic at the stellar surface in the general oblique rotator model, it is shown that a ondissipative flow branch which is sub-rotating when near the star remains sub-rotating everywhere, but that one which is super-rotating when near the star can become sub-rotating inside the light cylinder. Hence, both flow branches can cross the light cylinder and remain valid outside it.

scholarly journals Modeling Oblique Rotators: Magnetospheres and Winds

1999 ◽  
Vol 169 ◽  
pp. 178-186
Author(s):  
Steven N. Shore
Keyword(s):  
Main Sequence ◽  
Rotational Axis ◽  
Be Stars ◽  
Polar Caps ◽  
Rotator Model ◽  
Peculiar Stars ◽  
Oblique Rotator ◽  
Circumstellar Gas ◽  
Nonthermal Radio Emission ◽  
The Magnetic Field

AbstractThe upper main sequence chemically peculiar (CP) stars display evidence of trapped circumstellar gas and nonspherical outflows. These stars are also known to possess strong magnetic fields that are often highly inclined to the rotational axis. Their phenomenology can be understood by using the oblique rotator model, which has successfully accounted for the observed behavior of the cooler CP stars. This paper reviews some features of the oblique rotator model, in which the magnetic field is assumed to provide a rigid framework for the structuring of the stellar and circumstellar gas. Corotation of circumstellar plasma is enforced out to the Alfven radius in the magnetic equatorial plane, while for the hotter stars, a radiatively driven wind emerges from the magnetic polar caps. Some observable consequences of the model are discussed, especially the Hα and ultraviolet resonance line absorption and emission periodic variability that has been observed in the He-peculiar stars and nonthermal radio emission. Magnetospheres may also be present in O stars, e.g. θ1 Ori C, and in the Herbig Ae/Be stars.

A Study of Line Profiles in The Oblique Rotator Model and a Comparison with the Ap Star B Coronae Borealis.

1976 ◽  
Vol 32 ◽  
pp. 611-612
Author(s):  
R. Freedman
Keyword(s):  
Magnetic Field ◽  
Polarized Light ◽  
Line Profiles ◽  
Circularly Polarized Light ◽  
Rotator Model ◽  
Oblique Rotator ◽  
Left And Right ◽  
Effects Of Rotation ◽  
Ap Stars ◽  
The Magnetic Field

A study was made of line profiles in left and right circularly polarized light for the Ap stars βCrB. The model adopted for the surface configuration of the magnetic field was that of Wolff and Wolff (1970) who used an oblique rotator offset along the axis of the dipole field. The line profiles were calculated in pure absorption using the method of Rachovsky (1969). Allowance was made for the depth dependence of all relevant physical variables, arbitrary angles of the magnetic field, and the effect of anomalous dispersion. The elements studied were Ce II, Gd II, Mn I and Fe I. In general, weak, unsaturated lines were chosen for analysis. The final profiles were corrected for the effects of rotation.

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