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UBVI and Ha Photometry of the h & chi Persei cluster

Stefan C. Keller·Eva K. Grebel·Grant Miller·Kenneth Yoss
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Abstract

UBVI and Ha photometry is presented for 17319 stars in vicinity of the young double cluster h & chi Persei. Our photometry extends over a 37arcmin x 1arcdeg field centered on the association. We construct reddening contours within the imaged field. We find that the two clusters share a common distance modulus of 11.75$\pm$0.05 and ages of log age(yr) = 7.1$\pm$0.1. From the V-Ha colour, a measure of the Ha emission strength, we conduct a survey for emission line objects within the association. We detect a sample of 33 Be stars, 8 of which are new detections. We present a scenario of evolutionary enhancement of the Be phenomenon to account for the peak in Be fraction towards the top of the main-sequence in the population of h & chi Persei and similar young clusters.

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Stefan C. Keller, Eva K. Grebel, Grant Miller, Kenneth Yoss. 2001-05-02. UBVI and Ha Photometry of the h & chi Persei cluster. https://doi.org/10.1086/321139

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