0000000000787192
AUTHOR
S. J. Unger
Infrared and optical observations of the newly identified Be/X-ray binary LSI + 61 235
Observational (IR) and optical data are presented of the newly discovered Be/X-ray binary system LSI + 61° 235, taken over the period 1991 August – 1992 May. Though the IR shows little evidence for any changes, the optical Hα spectrum has undergone substantial modification. Combination of optical photometric measurements with the IR photometry allows the overall spectrum to be investigated and the existence of the Be star’s circumstellar disc to be directly confirmed.
A phase change in X Persei
We present a series of optical spectroscopic and infrared photometric observations of the Be/X-ray binary system X Per made over the last four years. Over this period the Hα line profile changed from emission to absorption, accompanied by a decrease in the infrared flux by over a magnitude and a flattening of the infrared spectrum. Such behaviour is consistent with the loss of the circumstellar disc or shell of material around the Be star and the reversion to a normal O/B-type star.
Photometric and Hα Observations of LSI+61°303
The Be massive X-ray binary LSI+61°303 is a 26.5 days periodic radiosource (Taylor & Gregory, 1984), exhibiting radio outbursts maxima between phases 0.6-0.8. Evidence of a photometric period of similar value has also been reported (Paredes & Figueras, 1986; Mendelson & Mazeh, 1989). The previous spectroscopic radial velocity observations of Hutchings & Crampton (1981) are in agreement with the radio period, and give support to the presence of a companion. We present new optical and infrared photometric observations and high resolution Hα spectra of LSI+61°303.