摘要
利用AZ Cas在1975年食期间的新观测,主要是Tempesti和我们的资料,改善了它的测光数据,并澄清了一些过去在资料很不完整的基础上的猜测性结论,求出了新的历元和初步的测光轨道根数.
The information about the system AZ cassiopeiae was very sparse because of its long period. But now the situation is quite improved. During its recent (1975) eclipse new observations are obtained. Tempesti (1980) observed it photoelectrically from January 1966 to September 1978 with the 40 cm refractor of the Teramo Observatory and more than an entire cycle is covered. Unfortunately the egress phase is not included. And the observations performed by Li et al. (1981) with the photoelectric photometer attached to the 60 cm Cassegrain reflector at Xing Long Observing Station of Beijing Observatory from September 1975 to December 1976 do not include the ingress phase. They are made up deficiency by each other so well that a decending branch and an ascending branch (eclipse of 1975) are covered. With these and others are determined the period P=3403d.6±0.6, the duration of the eclipse D=110d, the duration of the totality d=94d and the new ephemeris for minimum as Min=J.D. 2442691+3403.6(±0.6) E.In Table 1 are reported the photoelectric contact times. It is seen that the 4th contacts during the 1975 eclipse are different in different wavelengths. This reflects the effects of the eclipse pf the atmosphere. In Figure 1 are presented the u. b. y. light-curves (variable minus comparison star) observed by Li et al. (1981). The temporary and photometric characteristics of this variable are reported in Tables 3, 4 and 5.The elementary photometric elements are obtained by Russell-Merrill method only with our observation in blue wavelength and the results are shown in Table 6. Because of the differences between Tempesti's observations and ours they could not be merged into a single whole.Finally, some issues are discussed. The sum of masses of two components is 32M consistent with cowley et al. (1978). But their conclusion that the durations of the totality increase with time is not confirmed. According to the spectral results of Cowley et al. the eclipse occurred near periastron. It is likely that the duration of the egress phase may be shorter than that of the ingress because the orbital velocity of the companion during the egress phase is greater than that during the ingress, which is consistent with our observations.
