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We obtained deep near-infrared images of Sh 2-208, one of thelowest-metallicity HII regions in the Galaxy, [O/H] = -0.8 dex. We detected ayoung cluster in the center of the HII region with a limiting magnitude of K =18.0 mag (10sigma), which corresponds to a mass detection limit of ~0.2 M_sun.This enables the comparison of star-forming properties under low metallicitywith those of the solar neighborhood. We identified 89 cluster members. Fromthe fitting of the K-band luminosity function (KLF), the age and distance ofthe cluster are estimated to be ~0.5 Myr and ~4 kpc, respectively. Theestimated young age is consistent with the detection of strong CO emission inthe cluster region and the estimated large extinction of cluster members (Av ~4--25 mag). The observed KLF suggests that the underlying initial mass function(IMF) of the low-metallicity cluster is not significantly different fromcanonical IMFs in the solar neighborhood in terms of both high-mass slope andIMF peak (characteristic mass). Despite the very young age, the disk fractionof the cluster is estimated at only 27pm6 %, which is significantly lower thanthose in the solar metallicity. Those results are similar to Sh 2-207, which isanother low-metallicity star-forming region close to Sh 2-208 with a separationof 12 pc,suggesting that their star-forming activities in low-metallicityenvironments are essentially identical to those in the solar neighborhood,except for the disk dispersal timescale. From large-scale mid-infrared images,we suggest that sequential star formation is taking place in Sh 2-207, Sh 2-208and the surrounding region, triggered by an expanding bubble with a ~30 pcradius.

Low-metallicity Young Clusters in the Outer Galaxy. II. Sh 2-208