Long-term Spectroscopic and Near-Infrared Monitoring of Be/X-ray Binaries

Abstract

A long-term monitoring of 13 Be/X-ray binaries and 34 Be stars have been carried out with the 1.26 m reflector and the 2.16 m telescope at Xinglong Station. The observations cover the period of about 13 years in the optical spectroscopy and about 5 years in the near-infrared photometry. We present the monitoring results of two sources, X Persei and LSI +65°010, in the program. We detect changes of Hα EWs and JHK magnitudes in X Persei which reflect the formation of the extensive and dense envelope. The JHK magnitudes increase and decay rapidly while the variation of the Hα is wild. The behavior is suggestive of the envelope with different optical depth. The red-shift component in LSI +65°010 have been found in the monitoring program. The component may be brought from the neutron star with the movement in the line of sight.