The X-Ray Emission from Pms Stars in Taurus-Auriga, and the Relationship with Other Diagnostics of Activity

Abstract

We present a systematic study of the X-ray emission of pre-main-sequence stars in the Taurus-Auriga complex; the sample consists of all catalogued stars in this region observed with the Einstein Observatory, resulting in a total of 69 of served stars, 53 of which identified with X-ray sources. We present the X-ray luminosity functions, based on detections and upper limits, for the total sample and for suitably chosen subsamples. We find a definite inverse relation between the X-ray luminosity and the square of the rotational period for the classical T Tauri stars. Moreover an inverse relation exists between the X-ray luminosity and the H-alpha emission, expressed as the ratio between the H-alpha and 25-micron far-infrared luminosity, indicator of disk emission. We argue that this indicates a real inhibition of the wind emission in the most X-ray active T Tauri stars and we suggest a picture in which this phenomenon is likely to take place.