Is one month of observations enough? A case study on Kepler-21



We present the asteroseismic analysis of Kepler observations of the bright oscillating star Kepler-21 (KIC 3632418, KOI 975, HD 179070). The pulsation modes exhibited by this star are similar to the acoustic p-modes seen in our Sun. The analysis of observations covering a time period of 460 days has showed that the star hosts a small planet (Kepler-21b), which has a mass of ∼10 MEarth, a radius of 1.64±0.04 REarth and a revolving period of 2.8 days (Howell et al. 2012). Our current work deals with the comparison of p-mode frequency estimation using 1 and 10 months of observations (Quarter 2.3 and Quarters 5 through 7) of this F5 subgiant (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)