SCYON Abstract

Received on August 21 2001

UBVI and Halpha Photometry of the h and Chi Persei Cluster

AuthorsS.C. Keller (1), E.K. Grebel (2), G. Miller (3), K. Yoss (4)
Affiliation(1) Institute of Geophysics and Planetary Physics, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 9455
(2) Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany
(3) Southwestern College, 900 Otay Lakes Road, Chula Vista, CA 91910
(4)Department of Astronomy, University of Illinois at Urbana-Champaign, 1002 West Green Street, Urbana, IL 61801
Accepted byAstronomical Journal (vol. 122, 248, July 2001)
Links NGC 869 / NGC 884


UBVI and Halpha photometry is presented for 17319 stars in vicinity of the young double cluster h and chi Persei. Our photometry extends over a 37'×1deg 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 ± 0.05 and ages of logage(yr) = 7.1 ± 0.1. From the V-Halpha color, a measure of the Halpha emission strength, we conduct a survey for emission line objects within the association. We detect a sample of 33 Be stars, eight of which are new detections. We present a scenario of evolutionary enhancement of the Be phenomenon to account for the peak in Be fraction toward the top of the main sequence in the population of h and chi Persei and similar young clusters.