Extraction of seismic indices and stellar granulation parameters for CoRoT and Kepler red giants using the MLEUP method. Main results and perspectives

Abstract

In the framework of the SPACEInn project, a Stellar Seismic Indices (SSI - http://ssi.lesia.obspm.fr/) database was developed in order to provide the scientific community with oscillations and granulation signatures for a large set of red-giant type stars. For this purpose, we have developed the method MLEUP able to extract simultaneously the seismic indices (the equidistance Δv, the frequency vmax and the height Henv of the maximum oscillation power) and granulation parameters (the e-folding time τeff and the variance of the integrated brightness fluctuations σ2). This method has been tested in terms of precision and accuracy, using Monte Carlo simulations. Then we applied it to all stars observed by CoRoT and all long-cadence Kepler lightcurves. In total, we yield seismic indices and granulation parameters for about 5,000 stars for CoRoT and more than 13,000 for Kepler. In this paper, we focus on the main results for both seismic indices Δv and vmax as well as for the stellar parameters (mass, radius and luminosity) seismically inferred. Then, in the perspective of Gaia, we discuss about the possibility to derive other seismic quantities like e.g. a seismic effective temperature.