Effect of metallicity on the detectability of rotational periods in solar-like stars

Abstract

Accurate determination of stellar rotation periods is important for estimating stellar ages as well as for understanding stellar activity and evolution. While for about thirty thousand stars in the Kepler field rotation periods can be determined, there are over hundred thousand stars, especially with low photometric variability and irregular pattern of variations, for which rotational periods are unknown. Here, we investigate the effect of metallicity on the detectability of rotation periods. This is done by synthesising light curves of hypothetical stars, which are identical to our Sun, with the exception of the metallicity. These light curves are then used as an input to the period determination algorithms. We find that the success rate for recovering the rotation signal has a minimum close to the solar metallicity value. This can be explained by the compensation effect of facular and spot contributions. In addition, selecting solar-like stars with near-solar effective temperature, near solar photometric variability, and with metallicity between M/H = -0.35 and M/H = 0.35 from the Kepler sample, we analyse the fraction of stars for which rotational periods have been detected as a function of metallicity. In agreement with our theoretical estimate we found a local minimum for the detection fraction close to the solar metallicity. We further report rotation periods of 87~solar-like Kepler stars for the first time.

9 pages, 7 figures, accepted in A&A

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• Detectability of Rotational Modulation in Kepler Sun-like Stars as a Function of Age
• Where have all the solar-like stars gone? Rotation period detectability at various inclinations and metallicities
• Irradiance Variations of the Sun and Sun-Like Stars -- Overview of Topical Collection
• Connecting measurements of solar and stellar brightness variations
• Measuring periods in aperiodic light curves -- Applying the GPS method to infer rotation periods of solar-like stars
• Forward modelling of brightness variations in Sun-like stars -- II. Light curves and variability