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Session 93 - Binary and Variable Stars.
Oral session, Friday, January 09

[93.07] A Search for Causality Between the X-ray and Nonthermal Radio Emission from O Stars

W. L. Waldron (SAC), S. A. Drake, M. F. Corcoran (GSFC/USRA), S. Kitamoto (Osaka Univ.)

The observed X-ray and highly variable nonthermal radio emission from OB stars has eluded explanation for more than 15 years. The most favorable model of X-ray production in these stars (stellar wind shocks) predicts that both nonthermal radio emission and nonthermal X-ray emission above 2 keV should be present. The model suggests that the variability of this nonthermal X-ray component should be comparable to the radio variability for the case of a propagating wind disturbance. In addition, since the spatial separation between the X-ray and radio emission locations can range from ten to several hundred stellar radii, a time lag is expected in the variability of the two emission processes. To understand the causality between the X-ray and radio emission, we obtained ASCA and multi-wavelength (2, 3.6, 6 and 20 cm) VLA observations over a 3 week time span in 1997 from late September to mid October of a well known nonthermal radio and strong X-ray source, 9 Sgr, an O4V((f)) star. We present our preliminary analysis of the X-ray and radio data and discuss the implications of our results relevant to the proposed models.

Program listing for Friday