SCYON Abstract

Received on August 21 2001

UBVI and Halpha Photometry of the h and Chi Persei Cluster

Authors	S.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 by	Astronomical Journal (vol. 122, 248, July 2001)
Contact	skeller@igpp.ucllnl.org
URL
Links	NGC 869 / NGC 884

Abstract

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.