Joint H-alpha and X-ray Observations of Massive X-ray Binaries. I. The B-Supergiant System LS I +65 010 = 2S 0114+650

E. D. Grundstrom, J. L. Blair, D. R. Gies, W. Huang, M. V. McSwain, D. Raghavan, R. L. Riddle, J. P. Subasavage, D. W. Wingert, A. M. Levine, R. A. Remillard

Published 2006-10-30Version 1

We report on a three year spectroscopic monitoring program of the H-alpha emission in the massive X-ray binary LS I +65 010 = 2S 0114+650, which consists of a B-supergiant and a slowly rotating X-ray pulsar. We present revised orbital elements that yield a period of P=11.5983 +/- 0.0006 d and confirm that the orbit has a non-zero eccentricity e=0.18 +/- 0.05. The H-alpha emission profile is formed in the base of the wind of the B-supergiant primary, and we show how this spectral feature varies on timescales that are probably related to the rotational period of the B-supergiant. We also examine the X-ray fluxes from the Rossi X-ray Timing Explorer All-Sky Monitor instrument, and we show that the X-ray orbital light curve has a maximum at periastron and a minimum at the inferior conjunction of the B-supergiant. We also show that the wind emission strength and the high energy X-ray flux appear to vary in tandem on timescales of approximately a year.