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(Abridged version) We present the first detailed imaging polarizationobservations of six SMC and six LMC clusters, known to have large populationsof B-type stars which exhibit excess H-alpha emission, to constrain theevolutionary status of these stars and hence better establish links between theonset of disk formation in classical Be stars and cluster age and/ormetallicity. The wavelength dependence of our intrinsic polarization dataprovides a diagnostic of the dominant and any secondary polarigenic agentspresent, enabling us to discriminate pure gas disk systems, i.e. classical Bestars, from composite gas plus dust disk systems, i.e. Herbig Ae/Be or B[e]stars. Our intrinsic polarization results, along with available near-IR colorinformation, strongly supports the suggestion of Wisniewski et al. thatclassical Be stars are present in clusters of age 5-8 Myr, and contradictassertions that the Be phenomenon only develops in the second half of a Bstar's main sequence lifetime, i.e. no earlier than 10 Myr.  Comparing the polarimetric properties of our dataset to a similar survey ofGalactic classical Be stars, we find that the prevalence of polarimetric Balmerjump signatures decreases with metallicity. We speculate that these resultsmight indicate that either it is more difficult to form large disk systems inlow metallicity environments, or that the average disk temperature is higher inthese low metallicity environments. We have characterized the polarimetricsignatures of all candidate Be stars in our data sample and find ~25% areunlikely to arise from true classical Be star-disk systems.

astrophysical journal/the astrophysical journal

The Role of Evolutionary Age and Metallicity in the Formation of  Classical Be Circumstellar Disks II. Assessing the Evolutionary Nature of  Candidate Disk Systems