Spectral classification in H and chi Persei

New spectral types on the MK system are given for stars in the extreme nuclei of the Double Cluster to magnitude 12.0 and 11.7 in h and x Persei, respectively. H-R diagrams for the two clusters are presented. It is seen that the Be stars in Persei lie in an absolute magnitude interval of 0.8, in good agreement with Schmidt-Kaler's findings for Be stars of the general field. However, for a cluster distance modulus of 11.8, the absolute magnitude of the center of the interval containing the Be stars differs from that given by Schmidt-Kaler by 0.3 mag. From the H-R diagrams it is seen that h Persei is less evolved than x.

Hali tarjima qilinmagan