  Classical T Tauri stars (CTTS) are young (< 10 Myr), cool stars that actively
accrete matter from a disk. They show strong, broad and asymmetric, atomic FUV
emission lines. Neither the width, nor the line profile is understood. Likely,
different mechanisms influence the line profile; the best candidates are
accretion, winds and stellar activity. We monitored the C IV 1548/1550 Ang
doublet in the nearby, bright CTTS TW Hya with the Hubble Space Telescope
Cosmic Origin Spectrograph (HST/COS) to correlate it with i) the cool wind, as
seen in COS NUV Mg II line profiles, ii) the photometric period from joint
ground-based monitoring, iii) the accretion rate as determined from the UV
continuum, and iv) the Ha line profile from independent ground-based
observations. The observations span 10 orbits distributed over a few weeks to
cover the typical time scales of stellar rotation, accretion and winds. Here we
describe a model with intrinsically asymmetric C IV lines.
