Abstract
We predict the flux and surface velocity perturbations produced by convectively excited gravity modes (g-modes) in main-sequence stars. Core convection in massive stars can excite g-modes to sufficient amplitudes to be detectable with high-precision photometry by Kepler and Convection, Rotation and planetary Transits (CoRoT), if the thickness of the convective overshoot region is ≲30 per cent of a pressure scale height. The g-modes manifest as excess photometric variability, with amplitudes of ~10 μmag at frequencies ≲10 μHz (0.8 d-1) near the solar metallicity zero-age main sequence. The flux variations are largest for stars with M ≳ 5M⊙, but are potentially detectable down to M ~ 2-3M⊙. During the main-sequence evolution, radiative damping decreases such that ever lower frequency modes reach the stellar surface and flux perturbations reach up to ~100 μmag at the terminal-age main sequence. Using the same convective excitation model, we confirm previous predictions that solar gmodes produce surface velocity perturbations of≲0.3mm s-1. This implies that stochastically excited g-modes are more easily detectable in the photometry of massive main-sequence stars than in the Sun.
Original language | English (US) |
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Pages (from-to) | 1736-1745 |
Number of pages | 10 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 430 |
Issue number | 3 |
DOIs | |
State | Published - Apr 11 2013 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science
Keywords
- Convection
- Stars: interiors
- Stars: oscillations