SOME CHARACTERISTICS OF THE YOUNG OPEN CLUSTER TRUMPLER 37.

Abstract

ABSTRACT New MK classifications (51 stars) and UBV magnitudes (37 stars) are presented for stars in the region of the cluster Trumpler 37, which is the nucleus of the association I Cephei (Cep OB 2). These are com bined with additional UBV magnitudes from Simonson (1968) and compared with the H-R diagram of upper Scorpius to derive a distance modulus of . The relationship of the supergiant Cep to the rest of the association is discussed and an absolute magnitude of -7.7 is derived if it is assumed to be a member. Key words: UBV photometry - MK spectral classification - clusters - associations