S. Shukla, D. Weintraub (Vanderbilt University), J. Kastner (Rochester Institute of Technology)
Pre main sequence stars emit X-rays, indicative of the presence of strong magnetic fields. The production of strong X-rays is thought to be related to magnetic reconnection events (MREs). The stimuli of the MREs that generate the X-rays, however, is still a subject of considerable debate. Is the stimulus dynamo activity (fast rotation) or accretion (star-disk interactions)? If PMS stars are like MS stars, fast rotation generates coronal X-rays; however, evidence exists that X-rays from some classical T Tauri stars (cTTS) may be generated through disk-star MREs and/or shocks associated with accretion. To test these hypotheses, we are undertaking a program of Chandra observations of coeval binary TTS systems. Using Chandra’s Advanced CCD Imaging Spectrometer, we have observed V710 Tau, a binary system consisting of one cTTS, V710 Tau N, and one weak-lined T Tauri star (wTTS), V710 Tau S. The CXO/ACIS-S3 images, obtained in a 10 ks exposure on 29 December 2004, cleanly resolve the V710 Tau binary, and demonstrate that both stars emit X-rays. Preliminary results indicate that harder and more numerous X-rays are emitted from the cTTS than from the wTTS component. Since both stars appear nearly constant in count rate, neither the V710 Tau N/V710 Tau S X-ray flux ratio nor hardness ratio appears to be influenced by flaring. These data for this coeval binary contradict expectations that wTTS are more X-ray luminous than cTTS and that the star with the greater overall luminosity (in this case V710 Tau S) is more X-ray luminous. If the principle difference between the cTTS and the wTTS is the presence of active accretion in the cTTS, then the hard X-ray component may be associated with accretion. We present our analysis of the X-ray flux rates and spectral energy distributions of these stars from both December 2004 and April 2005 observations, and discuss whether wTTS and cTTS have unique spectral signatures that indicate the underlying conditions that generate the X-rays are different.
Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.