Solar-like oscillations

Solar-like oscillations are oscillations in stars that are excited in the same way as those in the Sun, namely by turbulent convection in its outer layers. Stars that show solar-like oscillations are called solar-like oscillators. The oscillations are standing pressure and mixed pressure-gravity modes that are excited over a range in frequency, with the amplitudes roughly following a bell-shaped distribution. Unlike opacity-driven oscillators, all the modes in the frequency range are excited, making the oscillations relatively easy to identify. The surface convection also damps the modes, and each is well-approximated in frequency space by a Lorentzian curve, the width of which corresponds to the lifetime of the mode: the faster it decays, the broader is the Lorentzian. All stars with surface convection zones are expected to show solar-like oscillations, including cool main-sequence stars (up to surface temperatures of about 7000K), subgiants and red giants. Because of the small amplitudes of the oscillations, their study has advanced tremendously thanks to space-based missions[1] (mainly COROT and Kepler).

Solar-like oscillations have been used, among other things, to precisely determine the masses and radii of planet-hosting stars and thus improve the measurements of the planets' masses and radii.[2][3]

  1. ^ Chaplin, W. J.; Miglio, A. (2013). "Asteroseismology of Solar-Type and Red-Giant Stars". Annual Review of Astronomy and Astrophysics. 51 (1): 353–392. arXiv:1303.1957. Bibcode:2013ARA&A..51..353C. doi:10.1146/annurev-astro-082812-140938. S2CID 119222611.
  2. ^ Davies, G. R.; et al. (2016). "Oscillation frequencies for 35 Kepler solar-type planet-hosting stars using Bayesian techniques and machine learning". Monthly Notices of the Royal Astronomical Society. 456 (2): 2183–2195. arXiv:1511.02105. Bibcode:2016MNRAS.456.2183D. doi:10.1093/mnras/stv2593.
  3. ^ Silva Aguirre, V.; et al. (2015). "Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology". Monthly Notices of the Royal Astronomical Society. 452 (2): 2127–2148. arXiv:1504.07992. Bibcode:2015MNRAS.452.2127S. doi:10.1093/mnras/stv1388.