2010ApJ...723L.113Y

We studied near-infrared disk fractions of six young clusters in the low-metallicity environments with [O/H] ∼ -0.7 using deep JHK images with Subaru 8.2 m telescope. We found that disk fraction of the low-metallicity clusters declines rapidly in <1 Myr, which is much faster than the ∼5-7 Myr observed for the solar-metallicity clusters, suggesting that disk lifetime shortens with decreasing metallicity possibly with an ∼10^ Z ^ dependence. Since the shorter disk lifetime reduces the time available for planet formation, this could be one of the major reasons for the strong planet-metallicity correlation. Although more quantitative observational and theoretical assessments are necessary, our results present the first direct observational evidence that can contribute to explaining the planet-metallicity correlation.