SPITZER IRAC and JHKS observations of h and χ Persei:: Constraints on protoplanetary disk and massive cluster evolution at ∼107 years

We describe IRAC 3.6-8 mu m observations and ground-based near-IR JHK(s) photometry from Mimir and 2MASS of the massive double cluster h and chi Persei complete to J = 15.5 (M similar to 1.3 M-circle dot). Within 25' of the cluster centers we detect similar to 11,000 sources with J <= 15.5,similar to 7000 sources with [4.5] <= 15, and similar to 5000 sources with [8] <= 14.5. In both clusters the surface density profiles derived from the 2MASS data decline with distance from the cluster centers as expected for a bound cluster. Within 15' of the cluster centers, similar to 50% of the stars lie on a reddened similar to 13 Myr isochrone; at 15'-25' from the cluster centers, similar to 40% lie on this isochrone. Thus, the optical 2MASS color-magnitude diagrams indicate that h and chi Per are accompanied by a halo population with roughly the same age and distance as the two dense clusters. The double cluster lacks any clear IR excess sources for J <= 13.5 (similar to 2.7 M-circle dot). Therefore, disks around highmass stars disperse prior to similar to 10(7) yr. At least 2%-3% of the fainter cluster stars have strong IR excess at both [5.8] and [ 8]. About 4%-8% of sources slightly more massive than the Sun (similar to 1.4M(circle dot)) have IR excesses at [8]. Combined with the lack of detectable excesses for brighter stars, this result suggests that disks around lower mass stars have longer lifetimes. The IR excess population also appears to be larger at longer IRAC bands ([5.8], [8]) than at shorter IRAC/2MASS bands (K-s, [4.5]), a result consistent with an inside-out clearing of disks.