X Per新发射相的不寻常变化

对ＸＰｅｒ新发射相连续四年的光学光谱和近红外光度监测结果，ＸＰｅｒ近两年的变化不同寻常，主要表现以下两点：（１）尽管它的光学光度Ｖ星等只恢复至失去气壳前的亮度，但Ｈａ发射线等值宽度和近红外，Ｊ，Ｈ和Ｋ光度地超过了历史记录的最大值，分别达到了１６．３４Ａ和５．３＾ｍ，５．３＾ｍ和５．１＾ｍ，表明ＸＰｅｒ新发射相气南的密度和尺度较都大，（２）我们首次观测到ＸＰｅｒ近红外光度和Ｈα发射线等值宽度变化趋势

THE UNUSUAL PHENOMENA OF X PER IN THE NEW EMISSION PHASE

We present a series of optical spectroscopic and infrared photometric observationsof the Be / X - ray system X Per in 1992 - 95. Some phenomena in this newemission phase turn out to be unique in comparison with former observations. Firstalthough the V magnitude only recovered its original maximum brightness from 1974to 1991, the equivalent width (EW) of he emission line and JHK magnitudesexceeded the values recorded before, and this means that the circumstellar envelope ofX Per in the new emission phase is more extensive and denser. Second, we have forthe first time observed in X Per that the EW of Ha line increased rapidly while theJHK rnagnitudes declined considerably. Our optical spectroscopic data support therotating ring model of the envelope and confirm the existcnce of the double - ringstructure, with which the observed unusual phenomena may be fariy well interpreted.