Mon. Not. R. Astron. Soc., 474, 2774-2786 (2018/February-3)
Theory and evidence of global Rossby waves in upper main-sequence stars: r-mode oscillations in many Kepler stars.
SAIO H., KURTZ D.W., MURPHY S.J., ANTOCI V.L. and LEE U.
Abstract (from CDS):
Asteroseismic inference from pressure modes (p modes) and buoyancy, or gravity, modes (g modes) is ubiquitous for stars across the Hertzsprung-Russell diagram. Until now, however, discussion of r modes (global Rossby waves) has been rare. Here we derive the expected frequency ranges of r modes in the observational frame by considering the visibility of these modes. We find that the frequencies of r modes of azimuthal order m appear as groups at slightly lower frequency than m times the rotation frequency. Comparing the visibility curves for r modes with Fourier amplitude spectra of Kepler light curves of upper main-sequence B, A, and F stars, we find that r modes are present in many γ Dor stars (as first discovered by Van Reeth et al.), spotted stars, and so-called heartbeat stars, which are highly eccentric binary stars. We also find a signature of r modes in a frequently bursting Be star observed by Kepler. In the amplitude spectra of moderately to rapidly rotating γ Dor stars, r-mode frequency groups appear at lower frequency than prograde g-mode frequency groups, while in the amplitude spectra of spotted early A to B stars, groups of symmetric (with respect to the equator) r-mode frequencies appear just below the frequency of a structured peak that we suggest represents an approximate stellar rotation rate. In many heartbeat stars, a group of frequencies can be fitted with symmetric m = 1 r modes, which can be used to obtain rotation frequencies of these stars.
© 2017 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
binaries: eclipsing - stars: early-type - stars: oscillations - stars: rotation - starspots - stars: variables: general
Misprints: KIC 622381 = KIC 6222381, KIC 6954724 = KIC 6954726, KIC 9210493 = 9210943.
View the reference in ADS
To bookmark this query, right click on this link: simbad:2018MNRAS.474.2774S and select 'bookmark this link' or equivalent in the popup menu