2009/05/19 by W. J. Chaplin, G. Houdek, C. Karoff +2 · 76 citations
Physics and Astronomy · #Amplitude #Asteroseismology #Astronomy and Astrophysical Research #Astrophysics #Astrophysics and Star Formation Studies #Geometry #Mode (computer interface) #Observable #Optics #Physics #Scaling #Spectral density #Stars #Stellar, planetary, and galactic studies #Surface gravity #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/200911952
published in Astronomy and Astrophysics 500(2), L21-L24 (EDP Sciences) · letter accepted for publication in A&A
openalex publication_date 2009/05/19 · arxiv created 2009/05/28 · arxiv updated 2015/05/13 · openalex created_date 2022/10/03 · openalex updated_date 2026/07/31
<i>Context. <i/>Successful inference from asteroseismology relies on at least two factors: that the oscillations in the stars have amplitudes large enough to be clearly observable, and that the oscillations themselves be stable enough to enable precise measurements of mode frequencies and other parameters. Solar-like p modes are damped by convection, and hence the stability of the modes depends on the lifetime.<i>Aims. <i/>We seek a simple scaling relation between the mean lifetime of the most prominent solar-like p modes in stars, and the fundamental stellar parameters.<i>Methods. <i/>We base our search for a relation on the use of stellar equilibrium and pulsation computations of a grid of stellar models, and the first asteroseismic results on lifetimes of main-sequence, sub-giant and red-giant stars.<i>Results. <i/>We find that the mean lifetimes of all three classes of solar-like stars scale like (where <i>T<i/><sub>eff<sub/> is the effective temperature). When this relation is combined with the well-known scaling relation of Kjeldsen & Bedding for mode amplitudes observed in narrow-band intensity observations, we obtain the unexpected result that the height (the maximum power spectral density) of mode peaks in the frequency power spectrum scales as <i>g<i/><sup>-2<sup/> (where <i>g<i/> is the surface gravity). As it is the mode height (and not the amplitude) that fixes the S/N at which the modes can be measured, and as <i>g<i/> changes only slowly along the main sequence, this suggests that stars cooler than the Sun might be as good targets for asteroseismology as their hotter counterparts. When observations are instead made in Doppler velocity, our results imply that mode height does increase with increasing effective temperature.