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This study presents sensitive MIR photometry obtained with the Spitzer/IRACfor a young cluster in Sh 2-208 (S208) located in one of the lowest-metallicityHII regions in the Galaxy, ${\rm [O/H]} = -0.8$ dex. Previous studies suggestedthat the cluster is $\sim$0.5-Myr old and has a distance of $D = 4$ kpc, whichis consistent with the astrometric distance from Gaia EDR3. In $\sim$$3.5\times 4$-arcmin field, 96 sources were detected in at least one MIR band at$\ge$10$\sigma$, covering intermediate-mass stars with $\sim$1.0-$M_\odot$ massdetection limit. Total 41 probable cluster members were identified based on thespatial distributions of spectral-energy-distribution slopes derived from theNIR $K_S$ and IRAC bands and extinctions of the sources. The cumulativedistribution of the SED slopes for the S208 cluster was not significantlydifferent from those of other clusters in solar-metallicity environments withapproximately the same age for intermediate-mass stars, if one also considersnon-detected MIR sources identified as S208 cluster members from NIRobservations. This suggests that the degree of dust growth/settling does notsignificantly change with metallicities as different as $\sim$1 dex. Thefraction of stars with MIR disk emissions for the cluster members with$\ge$1-$M_\odot$ mass was 64%-93%, which is comparable to the results insolar-metallicity environments. Although this may suggest that dominantdisk-dispersal mechanisms for intermediate-mass stars have either no, or veryweak, dependence on metallicity, it can be argued alternatively that this maysuggest that the disk dispersal process does not work effectively at this youngstage.

Spitzer Mid-infrared Study of Sh 2-208: Evolution of Protoplanetary Disks in Low-metallicity Environments