  Determination of stellar age is a crucial task in astrophysics research.
Different methods are nowadays used either model dependent or based on
calibrated empirical relations. The most reliable results are generally
obtained when different methods are used in complementary way. We propose a new
method for the age determination of young stellar associations and open
clusters (ages < 125 Myr), which can allow to further constrain the age when
used together with other methods. We explore the amplitude of the photometric
variability in bins of color and rotation period of five young associations and
clusters spanning an interval of ages from 1-3 Myr to 625 Myr (Taurus, rho
Ophiuchi, Upper Scorpius, Pleiades, and Praesepe), which all have high-quality
time-series photometry from Kepler K2 campaigns. In the low-mass regime, we
find that stars with similar color and rotation period but different ages
exhibit different amplitudes of their photometric variability, with younger
stars showing a larger photometric variability than older stars. The decline of
photometric variability amplitude versus age in stars with similar color and
rotation period can be in principle calibrated and be adopted as an additional
empirical relation to constrain the age of young associations and open
clusters, provided that time-series photometry is available for their low-mass
members.
