Oscillations of Fast Rotating Stars: p-Modes in Centrifugally Flattened Polytropes

2004 ◽  
Vol 215 ◽  
pp. 414-415 ◽  
Author(s):  
F. Lignières ◽  
M. Rieutord
Keyword(s):  
Numerical Method ◽  
Centrifugal Force ◽  
Perturbation Methods ◽  
Mathematical Formalism ◽  
Rotating Stars ◽  
Oscillation Modes ◽  
Rapidly Rotating Stars ◽  
Fast Rotating

Oscillation modes of rapidly rotating stars have not yet been calculated with precision, rotational effects being generally approximated by perturbation methods. We developed a mathematical formalism and a numerical method which fully account for the deformation of the star by the centrifugal force. The method has been first tested in the case of Maclaurin spheroids and then applied to uniformly rotating polytropic stars.

scholarly journals Equilibrium structures of rapidly rotating stars with shellular rotation

2016 ◽  
Vol 12 (S329) ◽  
pp. 398-398
Author(s):  
Kotaro Fujisawa ◽  
Yu Yamamoto
Keyword(s):  
Numerical Method ◽  
Massive Stars ◽  
Core Collapse ◽  
Rotating Stars ◽  
Self Consistent ◽  
Equilibrium Structures ◽  
Rapidly Rotating Stars

AbstractWe have developed a new numerical method for obtaining self-consistent structures of rapidly rotating stars. We obtained self-consistent equilibrium structures of rapidly rotating massive stars with shellular rotation by using the method. These equilibrium structures might be useful for both evolution of rapidly rotating massive stars and progenitor models of core-collapse supernovae simulations.

scholarly journals Fast rotating stars resulting from binary evolution will often appear to be single

2010 ◽  
Vol 6 (S272) ◽  
pp. 531-532 ◽  
Author(s):  
Selma E. de Mink ◽  
Norbert Langer ◽  
Robert G. Izzard
Keyword(s):  
Binary System ◽  
Binary Systems ◽  
Large Fraction ◽  
Supernova Explosion ◽  
Binary Interaction ◽  
Close Binaries ◽  
Rotating Stars ◽  
Single Star ◽  
Rapidly Rotating Stars ◽  
Fast Rotating

AbstractRapidly rotating stars are readily produced in binary systems. An accreting star in a binary system can be spun up by mass accretion and quickly approach the break-up limit. Mergers between two stars in a binary are expected to result in massive, fast rotating stars. These rapid rotators may appear as Be or Oe stars or at low metallicity they may be progenitors of long gamma-ray bursts.Given the high frequency of massive stars in close binaries it seems likely that a large fraction of rapidly rotating stars result from binary interaction. It is not straightforward to distinguish a a fast rotator that was born as a rapidly rotating single star from a fast rotator that resulted from some kind of binary interaction. Rapidly rotating stars resulting from binary interaction will often appear to be single because the companion tends to be a low mass, low luminosity star in a wide orbit. Alternatively, they became single stars after a merger or disruption of the binary system during the supernova explosion of the primary.The absence of evidence for a companion does not guarantee that the system did not experience binary interaction in the past. If binary interaction is one of the main causes of high stellar rotation rates, the binary fraction is expected to be smaller among fast rotators. How this prediction depend on uncertainties in the physics of the binary interactions requires further investigation.

scholarly journals Rossby Waves in Astrophysics

2021 ◽  
Vol 217 (1) ◽  
Author(s):  
T. V. Zaqarashvili ◽  
M. Albekioni ◽  
J. L. Ballester ◽  
Y. Bekki ◽  
L. Biancofiore ◽  
...  
Keyword(s):  
Large Scale ◽  
Rossby Waves ◽  
Magnetic Activity ◽  
Future Research ◽  
Rotating Stars ◽  
Spatial And Temporal Scales ◽  
Physical Role ◽  
Astrophysical Objects ◽  
Exoplanetary Atmospheres ◽  
Rapidly Rotating Stars

AbstractRossby waves are a pervasive feature of the large-scale motions of the Earth’s atmosphere and oceans. These waves (also known as planetary waves and r-modes) also play an important role in the large-scale dynamics of different astrophysical objects such as the solar atmosphere and interior, astrophysical discs, rapidly rotating stars, planetary and exoplanetary atmospheres. This paper provides a review of theoretical and observational aspects of Rossby waves on different spatial and temporal scales in various astrophysical settings. The physical role played by Rossby-type waves and associated instabilities is discussed in the context of solar and stellar magnetic activity, angular momentum transport in astrophysical discs, planet formation, and other astrophysical processes. Possible directions of future research in theoretical and observational aspects of astrophysical Rossby waves are outlined.

scholarly journals Learning about Stellar Dynamos from Long–term Photometry of Starspots

1991 ◽  
Vol 130 ◽  
pp. 353-369 ◽  
Author(s):  
Douglas S. Hall
Keyword(s):  
Differential Rotation ◽  
Rotation Period ◽  
Turnover Time ◽  
Rotating Stars ◽  
Photometric Variability ◽  
Solar Type ◽  
Magnetic Cycles ◽  
The Many ◽  
Rapidly Rotating Stars

AbstractSpottedness, as evidenced by photometric variability in 277 late-type binary and single stars, is found to occur when the Rossby number is less than about 2/3. This holds true when the convective turnover time versus B–V relation of Gilliland is used for dwarfs and also for subgiants and giants if their turnover times are twice and four times longer, respectively, than for dwarfs. Differential rotation is found correlated with rotation period (rapidly rotating stars approaching solid-body rotation) and also with lobe-filling factor (the differential rotation coefficient k is 2.5 times larger for F = 0 than F = 1). Also reviewed are latitude extent of spottedness, latitude drift during a solar-type cycle, sector structure and preferential longitudes, starspot lifetimes, and the many observational manifestations of magnetic cycles.

scholarly journals P-modes in rapidly rotating stars: Looking for regular patterns in synthetic asymptotic spectra

2010 ◽  
Vol 331 (9-10) ◽  
pp. 1053-1056 ◽  
Author(s):  
F. Lignières ◽  
B. Georgeot ◽  
J. Ballot
Keyword(s):  
Rotating Stars ◽  
Rapidly Rotating Stars ◽  
Regular Patterns

scholarly journals Pulsations of rapidly rotating stars

2015 ◽  
Vol 579 ◽  
pp. A116 ◽  
Author(s):  
R.-M. Ouazzani ◽  
I. W. Roxburgh ◽  
M.-A. Dupret
Keyword(s):  
Rotating Stars ◽  
Rapidly Rotating Stars
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