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Session 40 - The Environment of Stars: From Protostars to the Main Sequence.
Display session, Tuesday, June 11
An ASCA X-ray observation of the active weak-lined T Tauri star V773 Tau was obtained over a one-day interval in September 1995. The observation caught the star in a state of high X-ray luminosity (L_x \sim 10^32.2 ergs s^-1) and provides new information on plasma properties and X-ray variability. The X-ray light curve shows a slow decline in count rate throughout the observation. The decline is not exponential, but is well-modeled as a sinusoid with a period of \approx3.3 d. This value is consistent with previous estimates of the stellar rotation period (2.89 - 3.43 d), indicating that the X-ray emission was undergoing rotational modulation at the time of the ASCA observation. High S/N spectra from the solid-state spectrometers reveal a multi-temperature plasma dominated by a superhot component at T \sim 40 million K, and the time evolution of plasma temperature and emission measure can be tracked during the decay.
Program listing for Tuesday