Jm. Oliveira et al., Magnetospheric accretion and winds on the T Tauri star SU Aurigae - Multi-spectral line variability and cross-correlation analysis, ASTRON ASTR, 362(2), 2000, pp. 615-627
SU Aurigae is a T Tauri star that was well monitored during the MUSICOS 96
multi-site campaign. We present the results of the spectroscopic analysis o
f the circumstellar environment of this star, particularly of the H alpha,
H beta, Na I D and He I D3 line profiles. The signatures of modulated outfl
ows and mass accretion events are analysed, as well as transient spectral f
eatures. We compute the cross-correlation function (CCF) of several pairs o
f (velocity bins in) spectral lines to better investigate the profiles' tem
poral variability. We found increasing time lags between the variability of
He I D3, Na I D and H beta. We propose this may be understood in terms of
azimuthal distortion of the magnetic field lines due to the different rotat
ion rates of the star and the disk. We find the slightly blueshifted absorp
tion features in H alpha, H beta and Na I D to be anti-correlated with the
accretion flow signatures, We propose that the transient absorption feature
s in the blue wings of H alpha, H beta and Na I D (signatures of mass outfl
ows), and flare brightenings are related to the disruption of distorted mag
netospheric field lines.