Visibilities and bolometric corrections for stellar oscillation modes observed by Kepler

Context. Kepler produces a large amount of data used for asteroseismological analyses, particularly of solar-like stars and red giants. The mode amplitudes observed in the Kepler spectral band have to be converted into bolometric amplitudes to be compared to models. Aims. We give a simple bolometric correction for the amplitudes of radial modes observed with Kepler, as well as the relative visibilities of non-radial modes. Methods. We numerically compute the bolometric correction c(K-bol) and mode visibilities for different effective temperatures T-eff within the range 4000-7500 K, using a similar approach to a recent one from the literature. Results. We derive a law for the correction to bolometric values: c(K-bol) = 1 + a(1)(T-eff -T-o) + a(2)(T-eff -T-o)(2), with T-o = 5934 K, a(1) = 1.349 x 10(-)4 K-1, and a(2) = -3.120 x 10(-9) K-2 or, alternatively, as the power law c(K-bol) = (T-eff/T-o) a with alpha = 0.80. We give tabulated values for the mode visibilities based on limb-darkening (LD), computed from ATLAS9 model atmospheres for T-eff is an element of [4000, 7500] K, log g is an element of [2.5, 4.5], and [M/H] is an element of [-1.0, + 1.0]. We show that using LD profiles already integrated over the spectral band provides quick and good approximations for visibilities. We point out the limits of these classical visibility estimations.